fpc/compiler/x86/aasmcpu.pas

{
    $Id$
    Copyright (c) 1998-2002 by Florian Klaempfl and Peter Vreman

    Contains the abstract assembler implementation for the i386

    * Portions of this code was inspired by the NASM sources
      The Netwide Assembler is Copyright (c) 1996 Simon Tatham and
      Julian Hall. All rights reserved.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
unit aasmcpu;

{$i fpcdefs.inc}

interface

    uses
      cclasses,globals,verbose,
      cpuinfo,cpubase,
      cgbase,
      symppu,symtype,symsym,
      aasmbase,aasmtai;

    const
      { "mov reg,reg" source operand number }
      O_MOV_SOURCE = 0;
      { "mov reg,reg" destination operand number }
      O_MOV_DEST = 1;

    { Operand types }
      OT_NONE      = $00000000;

      OT_BITS8     = $00000001;  { size, and other attributes, of the operand  }
      OT_BITS16    = $00000002;
      OT_BITS32    = $00000004;
      OT_BITS64    = $00000008;  { FPU only  }
      OT_BITS80    = $00000010;
      OT_FAR       = $00000020;  { this means 16:16 or 16:32, like in CALL/JMP }
      OT_NEAR      = $00000040;
      OT_SHORT     = $00000080;

      OT_SIZE_MASK = $000000FF;  { all the size attributes  }
      OT_NON_SIZE  = longint(not OT_SIZE_MASK);

      OT_SIGNED    = $00000100;  { the operand need to be signed -128-127 }

      OT_TO        = $00000200;  { operand is followed by a colon  }
                                 { reverse effect in FADD, FSUB &c  }
      OT_COLON     = $00000400;

      OT_REGISTER  = $00001000;
      OT_IMMEDIATE = $00002000;
      OT_IMM8      = $00002001;
      OT_IMM16     = $00002002;
      OT_IMM32     = $00002004;
      OT_IMM64     = $00002008;
      OT_IMM80     = $00002010;
      OT_REGMEM    = $00200000;  { for r/m, ie EA, operands  }
      OT_REGNORM   = $00201000;  { 'normal' reg, qualifies as EA  }
      OT_REG8      = $00201001;
      OT_REG16     = $00201002;
      OT_REG32     = $00201004;
      OT_REG64     = $00201008;
      OT_MMXREG    = $00201008;  { MMX registers  }
      OT_XMMREG    = $00201010;  { Katmai registers  }
      OT_MEMORY    = $00204000;  { register number in 'basereg'  }
      OT_MEM8      = $00204001;
      OT_MEM16     = $00204002;
      OT_MEM32     = $00204004;
      OT_MEM64     = $00204008;
      OT_MEM80     = $00204010;
      OT_FPUREG    = $01000000;  { floating point stack registers  }
      OT_FPU0      = $01000800;  { FPU stack register zero  }
      OT_REG_SMASK = $00070000;  { special register operands: these may be treated differently  }
                                 { a mask for the following  }
      OT_REG_ACCUM = $00211000;  { FUNCTION_RETURN_REG: AL, AX or EAX  }
      OT_REG_AL    = $00211001;    { REG_ACCUM | BITSxx  }
      OT_REG_AX    = $00211002;    { ditto  }
      OT_REG_EAX   = $00211004;    { and again  }
{$ifdef x86_64}
      OT_REG_RAX   = $00211008;
{$endif x86_64}
      OT_REG_COUNT = $00221000;  { counter: CL, CX or ECX  }
      OT_REG_CL    = $00221001;    { REG_COUNT | BITSxx  }
      OT_REG_CX    = $00221002;    { ditto  }
      OT_REG_ECX   = $00221004;    { another one  }
{$ifdef x86_64}
      OT_REG_RCX   = $00221008;
{$endif x86_64}
      OT_REG_DX    = $00241002;
      OT_REG_EDX   = $00241004;

      OT_REG_SREG  = $00081002;  { any segment register  }
      OT_REG_CS    = $01081002;  { CS  }
      OT_REG_DESS  = $02081002;  { DS, ES, SS (non-CS 86 registers)  }
      OT_REG_FSGS  = $04081002;  { FS, GS (386 extended registers)  }

      OT_REG_CDT   = $00101004;  { CRn, DRn and TRn  }
      OT_REG_CREG  = $08101004;  { CRn  }
      OT_REG_CR4   = $08101404;  { CR4 (Pentium only)  }
      OT_REG_DREG  = $10101004;  { DRn  }
      OT_REG_TREG  = $20101004;  { TRn  }

      OT_MEM_OFFS  = $00604000;  { special type of EA  }
                                 { simple [address] offset  }
      OT_ONENESS   = $00800000;  { special type of immediate operand  }
                                 { so UNITY == IMMEDIATE | ONENESS  }
      OT_UNITY     = $00802000;  { for shift/rotate instructions  }

      { Size of the instruction table converted by nasmconv.pas }
{$ifdef x86_64}
      instabentries = {$i x86_64no.inc}
{$else x86_64}
      instabentries = {$i i386nop.inc}
{$endif x86_64}
      maxinfolen    = 8;

    type
      TOperandOrder = (op_intel,op_att);

      tinsentry=packed record
        opcode  : tasmop;
        ops     : byte;
        optypes : array[0..2] of longint;
        code    : array[0..maxinfolen] of char;
        flags   : longint;
      end;
      pinsentry=^tinsentry;

      { alignment for operator }
      tai_align = class(tai_align_abstract)
         reg       : tregister;
         constructor create(b:byte);
         constructor create_op(b: byte; _op: byte);
         function calculatefillbuf(var buf : tfillbuffer):pchar;override;
      end;

      taicpu = class(taicpu_abstract)
         opsize    : topsize;
         constructor op_none(op : tasmop;_size : topsize);

         constructor op_reg(op : tasmop;_size : topsize;_op1 : tregister);
         constructor op_const(op : tasmop;_size : topsize;_op1 : aword);
         constructor op_ref(op : tasmop;_size : topsize;const _op1 : treference);

         constructor op_reg_reg(op : tasmop;_size : topsize;_op1,_op2 : tregister);
         constructor op_reg_ref(op : tasmop;_size : topsize;_op1 : tregister;const _op2 : treference);
         constructor op_reg_const(op:tasmop; _size: topsize; _op1: tregister; _op2: aword);

         constructor op_const_reg(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister);
         constructor op_const_const(op : tasmop;_size : topsize;_op1,_op2 : aword);
         constructor op_const_ref(op : tasmop;_size : topsize;_op1 : aword;const _op2 : treference);

         constructor op_ref_reg(op : tasmop;_size : topsize;const _op1 : treference;_op2 : tregister);

         constructor op_reg_reg_reg(op : tasmop;_size : topsize;_op1,_op2,_op3 : tregister);
         constructor op_const_reg_reg(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister;_op3 : tregister);
         constructor op_const_ref_reg(op : tasmop;_size : topsize;_op1 : aword;const _op2 : treference;_op3 : tregister);
         constructor op_reg_reg_ref(op : tasmop;_size : topsize;_op1,_op2 : tregister; const _op3 : treference);
         constructor op_const_reg_ref(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister;const _op3 : treference);

         { this is for Jmp instructions }
         constructor op_cond_sym(op : tasmop;cond:TAsmCond;_size : topsize;_op1 : tasmsymbol);

         constructor op_sym(op : tasmop;_size : topsize;_op1 : tasmsymbol);
         constructor op_sym_ofs(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint);
         constructor op_sym_ofs_reg(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint;_op2 : tregister);
         constructor op_sym_ofs_ref(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint;const _op2 : treference);

         procedure changeopsize(siz:topsize);

         function  GetString:string;
         procedure CheckNonCommutativeOpcodes;
      private
         FOperandOrder : TOperandOrder;
         procedure init(_size : topsize); { this need to be called by all constructor }
    {$ifndef NOAG386BIN}
      public
         { the next will reset all instructions that can change in pass 2 }
         procedure ResetPass1;
         procedure ResetPass2;
         function  CheckIfValid:boolean;
         function  Pass1(offset:longint):longint;virtual;
         procedure Pass2(sec:TAsmObjectdata);virtual;
         procedure SetOperandOrder(order:TOperandOrder);
         function is_nop:boolean;override;
         function is_move:boolean;override;
         function spill_registers(list:Taasmoutput;
                                  rgget:Trggetproc;
                                  rgunget:Trgungetproc;
                                  const r:Tsuperregisterset;
                                  var unusedregsint:Tsuperregisterset;
                                  const spilltemplist:Tspill_temp_list):boolean;override;
      protected
         procedure ppuloadoper(ppufile:tcompilerppufile;var o:toper);override;
         procedure ppuwriteoper(ppufile:tcompilerppufile;const o:toper);override;
         procedure ppubuildderefimploper(var o:toper);override;
         procedure ppuderefoper(var o:toper);override;
      private
         { next fields are filled in pass1, so pass2 is faster }
         inssize   : shortint;
         insoffset,
         LastInsOffset : longint; { need to be public to be reset }
         insentry  : PInsEntry;
         function  InsEnd:longint;
         procedure create_ot;
         function  Matches(p:PInsEntry):longint;
         function  calcsize(p:PInsEntry):longint;
         procedure gencode(sec:TAsmObjectData);
         function  NeedAddrPrefix(opidx:byte):boolean;
         procedure Swapoperands;
         function  FindInsentry:boolean;
    {$endif NOAG386BIN}
      end;

    procedure InitAsm;
    procedure DoneAsm;


implementation

     uses
       cutils,
       itx86att;

{*****************************************************************************
                              Instruction table
*****************************************************************************}

    const
     {Instruction flags }
       IF_NONE   = $00000000;
       IF_SM     = $00000001;        { size match first two operands  }
       IF_SM2    = $00000002;
       IF_SB     = $00000004;  { unsized operands can't be non-byte  }
       IF_SW     = $00000008;  { unsized operands can't be non-word  }
       IF_SD     = $00000010;  { unsized operands can't be nondword  }
       IF_AR0    = $00000020;  { SB, SW, SD applies to argument 0  }
       IF_AR1    = $00000040;  { SB, SW, SD applies to argument 1  }
       IF_AR2    = $00000060;  { SB, SW, SD applies to argument 2  }
       IF_ARMASK = $00000060;  { mask for unsized argument spec  }
       IF_PRIV   = $00000100;  { it's a privileged instruction  }
       IF_SMM    = $00000200;  { it's only valid in SMM  }
       IF_PROT   = $00000400;  { it's protected mode only  }
       IF_UNDOC  = $00001000;  { it's an undocumented instruction  }
       IF_FPU    = $00002000;  { it's an FPU instruction  }
       IF_MMX    = $00004000;  { it's an MMX instruction  }
       { it's a 3DNow! instruction  }
       IF_3DNOW  = $00008000;
       { it's a SSE (KNI, MMX2) instruction  }
       IF_SSE    = $00010000;
       { SSE2 instructions  }
       IF_SSE2   = $00020000;
       { SSE3 instructions  }
       IF_SSE3   = $00040000;
       { the mask for processor types  }
       {IF_PMASK  = longint($FF000000);}
       { the mask for disassembly "prefer"  }
       {IF_PFMASK = longint($F001FF00);}
       IF_8086   = $00000000;  { 8086 instruction  }
       IF_186    = $01000000;  { 186+ instruction  }
       IF_286    = $02000000;  { 286+ instruction  }
       IF_386    = $03000000;  { 386+ instruction  }
       IF_486    = $04000000;  { 486+ instruction  }
       IF_PENT   = $05000000;  { Pentium instruction  }
       IF_P6     = $06000000;  { P6 instruction  }
       IF_KATMAI = $07000000;  { Katmai instructions  }
       { Willamette instructions }
       IF_WILLAMETTE = $08000000;
       { Prescott instructions }
       IF_PRESCOTT = $09000000;
       IF_CYRIX  = $10000000;  { Cyrix-specific instruction  }
       IF_AMD    = $20000000;  { AMD-specific instruction  }
       { added flags }
       IF_PRE    = $40000000;  { it's a prefix instruction }
       IF_PASS2  = longint($80000000);  { if the instruction can change in a second pass }

     type
       TInsTabCache=array[TasmOp] of longint;
       PInsTabCache=^TInsTabCache;

     const
{$ifdef x86_64}
       InsTab:array[0..instabentries-1] of TInsEntry={$i x86_64ta.inc}
{$else x86_64}
       InsTab:array[0..instabentries-1] of TInsEntry={$i i386tab.inc}
{$endif x86_64}
     var
       InsTabCache : PInsTabCache;

     const
{$ifdef x86_64}
       { Intel style operands ! }
       opsize_2_type:array[0..2,topsize] of longint=(
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_BITS16,OT_BITS32,OT_BITS32,OT_BITS64,OT_BITS64,OT_BITS64,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         ),
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_BITS8,OT_BITS8,OT_BITS16,OT_BITS8,OT_BITS16,OT_BITS32,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         ),
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_NONE,OT_NONE,OT_NONE,OT_NONE,OT_NONE,OT_NONE,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         )
       );

      reg_ot_table : array[tregisterindex] of longint = (
        {$i r8664ot.inc}
      );
{$else x86_64}
       { Intel style operands ! }
       opsize_2_type:array[0..2,topsize] of longint=(
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_BITS16,OT_BITS32,OT_BITS32,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         ),
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_BITS8,OT_BITS8,OT_BITS16,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         ),
         (OT_NONE,
          OT_BITS8,OT_BITS16,OT_BITS32,OT_NONE,OT_NONE,OT_NONE,
          OT_BITS16,OT_BITS32,OT_BITS64,
          OT_BITS32,OT_BITS64,OT_BITS80,OT_BITS64,OT_BITS64,OT_BITS64,OT_NONE,
          OT_NEAR,OT_FAR,OT_SHORT
         )
      );

      reg_ot_table : array[tregisterindex] of longint = (
        {$i r386ot.inc}
      );
{$endif x86_64}


{****************************************************************************
                              TAI_ALIGN
 ****************************************************************************}

    constructor tai_align.create(b: byte);
      begin
        inherited create(b);
        reg:=NR_ECX;
      end;


    constructor tai_align.create_op(b: byte; _op: byte);
      begin
        inherited create_op(b,_op);
        reg:=NR_NO;
      end;


    function tai_align.calculatefillbuf(var buf : tfillbuffer):pchar;
      const
        alignarray:array[0..5] of string[8]=(
          #$8D#$B4#$26#$00#$00#$00#$00,
          #$8D#$B6#$00#$00#$00#$00,
          #$8D#$74#$26#$00,
          #$8D#$76#$00,
          #$89#$F6,
          #$90
        );
      var
        bufptr : pchar;
        j : longint;
      begin
        inherited calculatefillbuf(buf);
        if not use_op then
         begin
           bufptr:=pchar(@buf);
           while (fillsize>0) do
            begin
              for j:=0 to 5 do
               if (fillsize>=length(alignarray[j])) then
                break;
              move(alignarray[j][1],bufptr^,length(alignarray[j]));
              inc(bufptr,length(alignarray[j]));
              dec(fillsize,length(alignarray[j]));
            end;
         end;
        calculatefillbuf:=pchar(@buf);
      end;


{*****************************************************************************
                                 Taicpu Constructors
*****************************************************************************}

    procedure taicpu.changeopsize(siz:topsize);
      begin
        opsize:=siz;
      end;


    procedure taicpu.init(_size : topsize);
      begin
         { default order is att }
         FOperandOrder:=op_att;
         segprefix:=NR_NO;
         opsize:=_size;
{$ifndef NOAG386BIN}
         insentry:=nil;
         LastInsOffset:=-1;
         InsOffset:=0;
         InsSize:=0;
{$endif}
      end;


    constructor taicpu.op_none(op : tasmop;_size : topsize);
      begin
         inherited create(op);
         init(_size);
      end;


    constructor taicpu.op_reg(op : tasmop;_size : topsize;_op1 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=1;
         loadreg(0,_op1);
      end;


    constructor taicpu.op_const(op : tasmop;_size : topsize;_op1 : aword);
      begin
         inherited create(op);
         init(_size);
         ops:=1;
         loadconst(0,_op1);
      end;


    constructor taicpu.op_ref(op : tasmop;_size : topsize;const _op1 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=1;
         loadref(0,_op1);
      end;


    constructor taicpu.op_reg_reg(op : tasmop;_size : topsize;_op1,_op2 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadreg(0,_op1);
         loadreg(1,_op2);
      end;


    constructor taicpu.op_reg_const(op:tasmop; _size: topsize; _op1: tregister; _op2: aword);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadreg(0,_op1);
         loadconst(1,_op2);
      end;


    constructor taicpu.op_reg_ref(op : tasmop;_size : topsize;_op1 : tregister;const _op2 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadreg(0,_op1);
         loadref(1,_op2);
      end;


    constructor taicpu.op_const_reg(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadconst(0,_op1);
         loadreg(1,_op2);
      end;


    constructor taicpu.op_const_const(op : tasmop;_size : topsize;_op1,_op2 : aword);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadconst(0,_op1);
         loadconst(1,_op2);
      end;


    constructor taicpu.op_const_ref(op : tasmop;_size : topsize;_op1 : aword;const _op2 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadconst(0,_op1);
         loadref(1,_op2);
      end;


    constructor taicpu.op_ref_reg(op : tasmop;_size : topsize;const _op1 : treference;_op2 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadref(0,_op1);
         loadreg(1,_op2);
      end;


    constructor taicpu.op_reg_reg_reg(op : tasmop;_size : topsize;_op1,_op2,_op3 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=3;
         loadreg(0,_op1);
         loadreg(1,_op2);
         loadreg(2,_op3);
      end;


    constructor taicpu.op_const_reg_reg(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister;_op3 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=3;
         loadconst(0,_op1);
         loadreg(1,_op2);
         loadreg(2,_op3);
      end;


    constructor taicpu.op_reg_reg_ref(op : tasmop;_size : topsize;_op1,_op2 : tregister;const _op3 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=3;
         loadreg(0,_op1);
         loadreg(1,_op2);
         loadref(2,_op3);
      end;


    constructor taicpu.op_const_ref_reg(op : tasmop;_size : topsize;_op1 : aword;const _op2 : treference;_op3 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=3;
         loadconst(0,_op1);
         loadref(1,_op2);
         loadreg(2,_op3);
      end;


    constructor taicpu.op_const_reg_ref(op : tasmop;_size : topsize;_op1 : aword;_op2 : tregister;const _op3 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=3;
         loadconst(0,_op1);
         loadreg(1,_op2);
         loadref(2,_op3);
      end;


    constructor taicpu.op_cond_sym(op : tasmop;cond:TAsmCond;_size : topsize;_op1 : tasmsymbol);
      begin
         inherited create(op);
         init(_size);
         condition:=cond;
         ops:=1;
         loadsymbol(0,_op1,0);
      end;


    constructor taicpu.op_sym(op : tasmop;_size : topsize;_op1 : tasmsymbol);
      begin
         inherited create(op);
         init(_size);
         ops:=1;
         loadsymbol(0,_op1,0);
      end;


    constructor taicpu.op_sym_ofs(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint);
      begin
         inherited create(op);
         init(_size);
         ops:=1;
         loadsymbol(0,_op1,_op1ofs);
      end;


    constructor taicpu.op_sym_ofs_reg(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint;_op2 : tregister);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadsymbol(0,_op1,_op1ofs);
         loadreg(1,_op2);
      end;


    constructor taicpu.op_sym_ofs_ref(op : tasmop;_size : topsize;_op1 : tasmsymbol;_op1ofs:longint;const _op2 : treference);
      begin
         inherited create(op);
         init(_size);
         ops:=2;
         loadsymbol(0,_op1,_op1ofs);
         loadref(1,_op2);
      end;


    function taicpu.GetString:string;
      var
        i : longint;
        s : string;
        addsize : boolean;
      begin
        s:='['+std_op2str[opcode];
        for i:=0 to ops-1 do
         begin
           with oper[i]^ do
             begin
               if i=0 then
                s:=s+' '
               else
                s:=s+',';
               { type }
               addsize:=false;
               if (ot and OT_XMMREG)=OT_XMMREG then
                s:=s+'xmmreg'
               else
                 if (ot and OT_MMXREG)=OT_MMXREG then
                  s:=s+'mmxreg'
               else
                 if (ot and OT_FPUREG)=OT_FPUREG then
                  s:=s+'fpureg'
               else
                if (ot and OT_REGISTER)=OT_REGISTER then
                 begin
                   s:=s+'reg';
                   addsize:=true;
                 end
               else
                if (ot and OT_IMMEDIATE)=OT_IMMEDIATE then
                 begin
                   s:=s+'imm';
                   addsize:=true;
                 end
               else
                if (ot and OT_MEMORY)=OT_MEMORY then
                 begin
                   s:=s+'mem';
                   addsize:=true;
                 end
               else
                 s:=s+'???';
               { size }
               if addsize then
                begin
                  if (ot and OT_BITS8)<>0 then
                    s:=s+'8'
                  else
                   if (ot and OT_BITS16)<>0 then
                    s:=s+'16'
                  else
                   if (ot and OT_BITS32)<>0 then
                    s:=s+'32'
                  else
                    s:=s+'??';
                  { signed }
                  if (ot and OT_SIGNED)<>0 then
                   s:=s+'s';
                end;
             end;
         end;
        GetString:=s+']';
      end;


    procedure taicpu.Swapoperands;
      var
        p : POper;
      begin
        { Fix the operands which are in AT&T style and we need them in Intel style }
        case ops of
          2 : begin
                { 0,1 -> 1,0 }
                p:=oper[0];
                oper[0]:=oper[1];
                oper[1]:=p;
              end;
          3 : begin
                { 0,1,2 -> 2,1,0 }
                p:=oper[0];
                oper[0]:=oper[2];
                oper[2]:=p;
              end;
        end;
      end;


    procedure taicpu.SetOperandOrder(order:TOperandOrder);
      begin
        if FOperandOrder<>order then
         begin
           Swapoperands;
           FOperandOrder:=order;
         end;
      end;


    procedure taicpu.ppuloadoper(ppufile:tcompilerppufile;var o:toper);
      begin
        o.typ:=toptype(ppufile.getbyte);
        o.ot:=ppufile.getlongint;
        case o.typ of
          top_reg :
              ppufile.getdata(o.reg,sizeof(Tregister));
          top_ref :
            begin
              new(o.ref);
              ppufile.getdata(o.ref^.segment,sizeof(Tregister));
              ppufile.getdata(o.ref^.base,sizeof(Tregister));
              ppufile.getdata(o.ref^.index,sizeof(Tregister));
              o.ref^.scalefactor:=ppufile.getbyte;
              o.ref^.offset:=ppufile.getlongint;
              o.ref^.symbol:=ppufile.getasmsymbol;
            end;
          top_const :
            o.val:=aword(ppufile.getlongint);
          top_symbol :
            begin
              o.sym:=ppufile.getasmsymbol;
              o.symofs:=ppufile.getlongint;
            end;
          top_local :
            begin
              ppufile.getderef(o.localsymderef);
              o.localsymofs:=ppufile.getlongint;
            end;
        end;
      end;


    procedure taicpu.ppuwriteoper(ppufile:tcompilerppufile;const o:toper);
      begin
        ppufile.putbyte(byte(o.typ));
        ppufile.putlongint(o.ot);
        case o.typ of
          top_reg :
            ppufile.putdata(o.reg,sizeof(Tregister));
          top_ref :
            begin
              ppufile.putdata(o.ref^.segment,sizeof(Tregister));
              ppufile.putdata(o.ref^.base,sizeof(Tregister));
              ppufile.putdata(o.ref^.index,sizeof(Tregister));
              ppufile.putbyte(o.ref^.scalefactor);
              ppufile.putlongint(o.ref^.offset);
              ppufile.putasmsymbol(o.ref^.symbol);
            end;
          top_const :
            ppufile.putlongint(longint(o.val));
          top_symbol :
            begin
              ppufile.putasmsymbol(o.sym);
              ppufile.putlongint(longint(o.symofs));
            end;
          top_local :
            begin
              ppufile.putderef(o.localsymderef);
              ppufile.putlongint(longint(o.localsymofs));
            end;
        end;
      end;


    procedure taicpu.ppubuildderefimploper(var o:toper);
      begin
        case o.typ of
          top_local :
            o.localsymderef.build(tvarsym(o.localsym));
        end;
      end;


    procedure taicpu.ppuderefoper(var o:toper);
      begin
        case o.typ of
          top_ref :
            begin
              if assigned(o.ref^.symbol) then
               objectlibrary.derefasmsymbol(o.ref^.symbol);
            end;
          top_symbol :
            objectlibrary.derefasmsymbol(o.sym);
          top_local :
            o.localsym:=tvarsym(o.localsymderef.resolve);
        end;
      end;


    procedure taicpu.CheckNonCommutativeOpcodes;
      begin
        { we need ATT order }
        SetOperandOrder(op_att);

        if (
            (ops=2) and
            (oper[0]^.typ=top_reg) and
            (oper[1]^.typ=top_reg) and
           { if the first is ST and the second is also a register
             it is necessarily ST1 .. ST7 }
            ((oper[0]^.reg=NR_ST) or
             (oper[0]^.reg=NR_ST0))
           ) or
           { ((ops=1) and
            (oper[0]^.typ=top_reg) and
            (oper[0]^.reg in [R_ST1..R_ST7]))  or}
           (ops=0) then
          begin
            if opcode=A_FSUBR then
              opcode:=A_FSUB
            else if opcode=A_FSUB then
              opcode:=A_FSUBR
            else if opcode=A_FDIVR then
              opcode:=A_FDIV
            else if opcode=A_FDIV then
              opcode:=A_FDIVR
            else if opcode=A_FSUBRP then
              opcode:=A_FSUBP
            else if opcode=A_FSUBP then
              opcode:=A_FSUBRP
            else if opcode=A_FDIVRP then
              opcode:=A_FDIVP
            else if opcode=A_FDIVP then
              opcode:=A_FDIVRP;
          end;
        if (
            (ops=1) and
            (oper[0]^.typ=top_reg) and
            (getregtype(oper[0]^.reg)=R_FPUREGISTER) and
            (oper[0]^.reg<>NR_ST)
           ) then
         begin
           if opcode=A_FSUBRP then
             opcode:=A_FSUBP
           else if opcode=A_FSUBP then
             opcode:=A_FSUBRP
           else if opcode=A_FDIVRP then
             opcode:=A_FDIVP
           else if opcode=A_FDIVP then
             opcode:=A_FDIVRP;
         end;
      end;


{*****************************************************************************
                                Assembler
*****************************************************************************}

{$ifndef NOAG386BIN}

    type
      ea=packed record
        sib_present : boolean;
        bytes : byte;
        size  : byte;
        modrm : byte;
        sib   : byte;
      end;

    procedure taicpu.create_ot;
      {
        this function will also fix some other fields which only needs to be once
      }
      var
        i,l,relsize : longint;
      begin
        if ops=0 then
         exit;
        { update oper[].ot field }
        for i:=0 to ops-1 do
         with oper[i]^ do
          begin
            case typ of
              top_reg :
                begin
                  ot:=reg_ot_table[findreg_by_number(reg)];
                end;
              top_ref :
                begin
                  { create ot field }
                  if (ot and OT_SIZE_MASK)=0 then
                    ot:=OT_MEMORY or opsize_2_type[i,opsize]
                  else
                    ot:=OT_MEMORY or (ot and OT_SIZE_MASK);
                  if (ref^.base=NR_NO) and (ref^.index=NR_NO) then
                    ot:=ot or OT_MEM_OFFS;
                  { fix scalefactor }
                  if (ref^.index=NR_NO) then
                   ref^.scalefactor:=0
                  else
                   if (ref^.scalefactor=0) then
                    ref^.scalefactor:=1;
                end;
              top_local :
                begin
                  if (ot and OT_SIZE_MASK)=0 then
                    ot:=OT_MEMORY or opsize_2_type[i,opsize]
                  else
                    ot:=OT_MEMORY or (ot and OT_SIZE_MASK);
                end;
              top_const :
                begin
                  if (opsize<>S_W) and (longint(val)>=-128) and (val<=127) then
                    ot:=OT_IMM8 or OT_SIGNED
                  else
                    ot:=OT_IMMEDIATE or opsize_2_type[i,opsize];
                end;
              top_symbol :
                begin
                  if LastInsOffset=-1 then
                   l:=0
                  else
                   l:=InsOffset-LastInsOffset;
                  inc(l,symofs);
                  if assigned(sym) then
                   inc(l,sym.address);
                  { instruction size will then always become 2 (PFV) }
                  relsize:=(InsOffset+2)-l;
                  if (not assigned(sym) or
                      ((sym.currbind<>AB_EXTERNAL) and (sym.address<>0))) and
                     (relsize>=-128) and (relsize<=127) then
                   ot:=OT_IMM32 or OT_SHORT
                  else
                   ot:=OT_IMM32 or OT_NEAR;
                end;
            end;
          end;
      end;


    function taicpu.InsEnd:longint;
      begin
        InsEnd:=InsOffset+InsSize;
      end;


      function taicpu.Matches(p:PInsEntry):longint;
      { * IF_SM stands for Size Match: any operand whose size is not
       * explicitly specified by the template is `really' intended to be
       * the same size as the first size-specified operand.
       * Non-specification is tolerated in the input instruction, but
       * _wrong_ specification is not.
       *
       * IF_SM2 invokes Size Match on only the first _two_ operands, for
       * three-operand instructions such as SHLD: it implies that the
       * first two operands must match in size, but that the third is
       * required to be _unspecified_.
       *
       * IF_SB invokes Size Byte: operands with unspecified size in the
       * template are really bytes, and so no non-byte specification in
       * the input instruction will be tolerated. IF_SW similarly invokes
       * Size Word, and IF_SD invokes Size Doubleword.
       *
       * (The default state if neither IF_SM nor IF_SM2 is specified is
       * that any operand with unspecified size in the template is
       * required to have unspecified size in the instruction too...)
      }
      var
        i,j,asize,oprs : longint;
        siz : array[0..2] of longint;
      begin
        Matches:=100;

        { Check the opcode and operands }
        if (p^.opcode<>opcode) or (p^.ops<>ops) then
         begin
           Matches:=0;
           exit;
         end;

        { Check that no spurious colons or TOs are present }
        for i:=0 to p^.ops-1 do
         if (oper[i]^.ot and (not p^.optypes[i]) and (OT_COLON or OT_TO))<>0 then
          begin
            Matches:=0;
            exit;
          end;

        { Check that the operand flags all match up }
        for i:=0 to p^.ops-1 do
         begin
           if ((p^.optypes[i] and (not oper[i]^.ot)) or
               ((p^.optypes[i] and OT_SIZE_MASK) and
                ((p^.optypes[i] xor oper[i]^.ot) and OT_SIZE_MASK)))<>0 then
            begin
              if ((p^.optypes[i] and (not oper[i]^.ot) and OT_NON_SIZE) or
                  (oper[i]^.ot and OT_SIZE_MASK))<>0 then
               begin
                 Matches:=0;
                 exit;
               end
              else
               Matches:=1;
            end;
         end;

      { Check operand sizes }
        { as default an untyped size can get all the sizes, this is different
          from nasm, but else we need to do a lot checking which opcodes want
          size or not with the automatic size generation }
        asize:=longint($ffffffff);
        if (p^.flags and IF_SB)<>0 then
          asize:=OT_BITS8
        else if (p^.flags and IF_SW)<>0 then
          asize:=OT_BITS16
        else if (p^.flags and IF_SD)<>0 then
          asize:=OT_BITS32;
        if (p^.flags and IF_ARMASK)<>0 then
         begin
           siz[0]:=0;
           siz[1]:=0;
           siz[2]:=0;
           if (p^.flags and IF_AR0)<>0 then
            siz[0]:=asize
           else if (p^.flags and IF_AR1)<>0 then
            siz[1]:=asize
           else if (p^.flags and IF_AR2)<>0 then
            siz[2]:=asize;
         end
        else
         begin
         { we can leave because the size for all operands is forced to be
           the same
           but not if IF_SB IF_SW or IF_SD is set PM }
           if asize=-1 then
             exit;
           siz[0]:=asize;
           siz[1]:=asize;
           siz[2]:=asize;
         end;

        if (p^.flags and (IF_SM or IF_SM2))<>0 then
         begin
           if (p^.flags and IF_SM2)<>0 then
            oprs:=2
           else
            oprs:=p^.ops;
           for i:=0 to oprs-1 do
            if ((p^.optypes[i] and OT_SIZE_MASK) <> 0) then
             begin
               for j:=0 to oprs-1 do
                siz[j]:=p^.optypes[i] and OT_SIZE_MASK;
               break;
             end;
          end
         else
          oprs:=2;

        { Check operand sizes }
        for i:=0 to p^.ops-1 do
         begin
           if ((p^.optypes[i] and OT_SIZE_MASK)=0) and
              ((oper[i]^.ot and OT_SIZE_MASK and (not siz[i]))<>0) and
              { Immediates can always include smaller size }
              ((oper[i]^.ot and OT_IMMEDIATE)=0) and
               (((p^.optypes[i] and OT_SIZE_MASK) or siz[i])<(oper[i]^.ot and OT_SIZE_MASK)) then
            Matches:=2;
         end;
      end;


    procedure taicpu.ResetPass1;
      begin
        { we need to reset everything here, because the choosen insentry
          can be invalid for a new situation where the previously optimized
          insentry is not correct }
        InsEntry:=nil;
        InsSize:=0;
        LastInsOffset:=-1;
      end;


    procedure taicpu.ResetPass2;
      begin
        { we are here in a second pass, check if the instruction can be optimized }
        if assigned(InsEntry) and
           ((InsEntry^.flags and IF_PASS2)<>0) then
         begin
           InsEntry:=nil;
           InsSize:=0;
         end;
        LastInsOffset:=-1;
      end;


    function taicpu.CheckIfValid:boolean;
      begin
        result:=FindInsEntry;
      end;


    function taicpu.FindInsentry:boolean;
      var
        i : longint;
      begin
        result:=false;
      { Things which may only be done once, not when a second pass is done to
        optimize }
        if (Insentry=nil) or ((InsEntry^.flags and IF_PASS2)<>0) then
         begin
           { We need intel style operands }
           SetOperandOrder(op_intel);
           { create the .ot fields }
           create_ot;
           { set the file postion }
           aktfilepos:=fileinfo;
         end
        else
         begin
           { we've already an insentry so it's valid }
           result:=true;
           exit;
         end;
        { Lookup opcode in the table }
        InsSize:=-1;
        i:=instabcache^[opcode];
        if i=-1 then
         begin
           Message1(asmw_e_opcode_not_in_table,gas_op2str[opcode]);
           exit;
         end;
        insentry:=@instab[i];
        while (insentry^.opcode=opcode) do
         begin
           if matches(insentry)=100 then
             begin
               result:=true;
               exit;
             end;
           inc(i);
           insentry:=@instab[i];
         end;
        Message1(asmw_e_invalid_opcode_and_operands,GetString);
        { No instruction found, set insentry to nil and inssize to -1 }
        insentry:=nil;
        inssize:=-1;
      end;


    function taicpu.Pass1(offset:longint):longint;
      begin
        Pass1:=0;
        { Save the old offset and set the new offset }
        InsOffset:=Offset;
        { Things which may only be done once, not when a second pass is done to
          optimize }
        if Insentry=nil then
         begin
           { Check if error last time then InsSize=-1 }
           if InsSize=-1 then
            exit;
           { set the file postion }
           aktfilepos:=fileinfo;
         end
        else
         begin
{$ifdef PASS2FLAG}
           { we are here in a second pass, check if the instruction can be optimized }
           if (InsEntry^.flags and IF_PASS2)=0 then
            begin
              Pass1:=InsSize;
              exit;
            end;
           { update the .ot fields, some top_const can be updated }
           create_ot;
{$endif PASS2FLAG}
         end;
        { Get InsEntry }
        if FindInsEntry then
         begin
           { Calculate instruction size }
           InsSize:=calcsize(insentry);
           if segprefix<>NR_NO then
            inc(InsSize);
           { Fix opsize if size if forced }
           if (insentry^.flags and (IF_SB or IF_SW or IF_SD))<>0 then
             begin
               if (insentry^.flags and IF_ARMASK)=0 then
                 begin
                   if (insentry^.flags and IF_SB)<>0 then
                     begin
                       if opsize=S_NO then
                         opsize:=S_B;
                     end
                   else if (insentry^.flags and IF_SW)<>0 then
                     begin
                       if opsize=S_NO then
                         opsize:=S_W;
                     end
                   else if (insentry^.flags and IF_SD)<>0 then
                     begin
                       if opsize=S_NO then
                         opsize:=S_L;
                     end;
                 end;
             end;
           LastInsOffset:=InsOffset;
           Pass1:=InsSize;
           exit;
         end;
        LastInsOffset:=-1;
      end;


    procedure taicpu.Pass2(sec:TAsmObjectData);
      var
        c : longint;
      begin
        { error in pass1 ? }
        if insentry=nil then
         exit;
        aktfilepos:=fileinfo;
        { Segment override }
        if (segprefix<>NR_NO) then
         begin
           case segprefix of
             NR_CS : c:=$2e;
             NR_DS : c:=$3e;
             NR_ES : c:=$26;
             NR_FS : c:=$64;
             NR_GS : c:=$65;
             NR_SS : c:=$36;
           end;
           sec.writebytes(c,1);
           { fix the offset for GenNode }
           inc(InsOffset);
         end;
        { Generate the instruction }
        GenCode(sec);
      end;


    function taicpu.needaddrprefix(opidx:byte):boolean;
      begin
        needaddrprefix:=false;
        if (OT_MEMORY and (not oper[opidx]^.ot))=0 then
          begin
            if (
                (oper[opidx]^.ref^.index<>NR_NO) and
                (getsubreg(oper[opidx]^.ref^.index)<>R_SUBD)
               ) or
               (
                (oper[opidx]^.ref^.base<>NR_NO) and
                (getsubreg(oper[opidx]^.ref^.base)<>R_SUBD)
               ) then
              needaddrprefix:=true;
          end;
      end;


    function regval(r:Tregister):byte;
      const
    {$ifdef x86_64}
        opcode_table:array[tregisterindex] of tregisterindex = (
          {$i r8664op.inc}
        );
    {$else x86_64}
        opcode_table:array[tregisterindex] of tregisterindex = (
          {$i r386op.inc}
        );
    {$endif x86_64}
      var
        regidx : tregisterindex;
      begin
        regidx:=findreg_by_number(r);
        if regidx<>0 then
          result:=opcode_table[regidx]
        else
          begin
            Message1(asmw_e_invalid_register,generic_regname(r));
            result:=0;
          end;
      end;


    function process_ea(const input:toper;var output:ea;rfield:longint):boolean;
      var
        sym   : tasmsymbol;
        md,s,rv  : byte;
        base,index,scalefactor,
        o     : longint;
        ir,br : Tregister;
        isub,bsub : tsubregister;
      begin
        process_ea:=false;
        {Register ?}
        if (input.typ=top_reg) then
          begin
            rv:=regval(input.reg);
            output.sib_present:=false;
            output.bytes:=0;
            output.modrm:=$c0 or (rfield shl 3) or rv;
            output.size:=1;
            process_ea:=true;
            exit;
         end;
        {No register, so memory reference.}
        if ((input.ref^.index<>NR_NO) and (getregtype(input.ref^.index)<>R_INTREGISTER)) or
           ((input.ref^.base<>NR_NO) and (getregtype(input.ref^.base)<>R_INTREGISTER)) then
          internalerror(200301081);
        ir:=input.ref^.index;
        br:=input.ref^.base;
        isub:=getsubreg(ir);
        bsub:=getsubreg(br);
        s:=input.ref^.scalefactor;
        o:=input.ref^.offset;
        sym:=input.ref^.symbol;
      { it's direct address }
        if (br=NR_NO) and (ir=NR_NO) then
         begin
           { it's a pure offset }
           output.sib_present:=false;
           output.bytes:=4;
           output.modrm:=5 or (rfield shl 3);
         end
        else
        { it's an indirection }
         begin
           { 16 bit address? }
           if ((ir<>NR_NO) and (isub<>R_SUBD)) or
              ((br<>NR_NO) and (bsub<>R_SUBD)) then
             message(asmw_e_16bit_not_supported);
{$ifdef OPTEA}
           { make single reg base }
           if (br=NR_NO) and (s=1) then
            begin
              br:=ir;
              ir:=NR_NO;
            end;
           { convert [3,5,9]*EAX to EAX+[2,4,8]*EAX }
           if (br=NR_NO) and
              (((s=2) and (ir<>NR_ESP)) or
                (s=3) or (s=5) or (s=9)) then
            begin
              br:=ir;
              dec(s);
            end;
           { swap ESP into base if scalefactor is 1 }
           if (s=1) and (ir=NR_ESP) then
            begin
              ir:=br;
              br:=NR_ESP;
            end;
{$endif OPTEA}
           { wrong, for various reasons }
           if (ir=NR_ESP) or ((s<>1) and (s<>2) and (s<>4) and (s<>8) and (ir<>NR_NO)) then
            exit;
           { base }
           case br of
             NR_EAX : base:=0;
             NR_ECX : base:=1;
             NR_EDX : base:=2;
             NR_EBX : base:=3;
             NR_ESP : base:=4;
             NR_NO,
             NR_EBP : base:=5;
             NR_ESI : base:=6;
             NR_EDI : base:=7;
           else
             exit;
           end;
           { index }
           case ir of
             NR_EAX : index:=0;
             NR_ECX : index:=1;
             NR_EDX : index:=2;
             NR_EBX : index:=3;
             NR_NO  : index:=4;
             NR_EBP : index:=5;
             NR_ESI : index:=6;
             NR_EDI : index:=7;
           else
             exit;
           end;
           case s of
            0,
            1 : scalefactor:=0;
            2 : scalefactor:=1;
            4 : scalefactor:=2;
            8 : scalefactor:=3;
           else
            exit;
           end;
           if (br=NR_NO) or
              ((br<>NR_EBP) and (o=0) and (sym=nil)) then
            md:=0
           else
            if ((o>=-128) and (o<=127) and (sym=nil)) then
             md:=1
            else
             md:=2;
           if (br=NR_NO) or (md=2) then
            output.bytes:=4
           else
            output.bytes:=md;
           { SIB needed ? }
           if (ir=NR_NO) and (br<>NR_ESP) then
            begin
              output.sib_present:=false;
              output.modrm:=(md shl 6) or (rfield shl 3) or base;
            end
           else
            begin
              output.sib_present:=true;
              output.modrm:=(md shl 6) or (rfield shl 3) or 4;
              output.sib:=(scalefactor shl 6) or (index shl 3) or base;
            end;
         end;
        if output.sib_present then
         output.size:=2+output.bytes
        else
         output.size:=1+output.bytes;
        process_ea:=true;
      end;


    function taicpu.calcsize(p:PInsEntry):longint;
      var
        codes : pchar;
        c     : byte;
        len     : longint;
        ea_data : ea;
      begin
        len:=0;
        codes:=@p^.code;
        repeat
          c:=ord(codes^);
          inc(codes);
          case c of
            0 :
              break;
            1,2,3 :
              begin
                inc(codes,c);
                inc(len,c);
              end;
            8,9,10 :
              begin
                inc(codes);
                inc(len);
              end;
            4,5,6,7 :
              begin
                if opsize=S_W then
                  inc(len,2)
                else
                  inc(len);
              end;
            15,
            12,13,14,
            16,17,18,
            20,21,22,
            40,41,42 :
              inc(len);
            24,25,26,
            31,
            48,49,50 :
              inc(len,2);
            28,29,30, { we don't have 16 bit immediates code }
            32,33,34,
            52,53,54,
            56,57,58 :
              inc(len,4);
            192,193,194 :
              if NeedAddrPrefix(c-192) then
               inc(len);
            208 :
              inc(len);
            200,
            201,
            202,
            209,
            210,
            217,218,219 : ;
            216 :
              begin
                inc(codes);
                inc(len);
              end;
            224,225,226 :
              begin
                InternalError(777002);
              end;
            else
              begin
                if (c>=64) and (c<=191) then
                 begin
                   if not process_ea(oper[(c shr 3) and 7]^, ea_data, 0) then
                    Message(asmw_e_invalid_effective_address)
                   else
                    inc(len,ea_data.size);
                 end
                else
                 InternalError(777003);
              end;
          end;
        until false;
        calcsize:=len;
      end;


    procedure taicpu.GenCode(sec:TAsmObjectData);
      {
       * the actual codes (C syntax, i.e. octal):
       * \0            - terminates the code. (Unless it's a literal of course.)
       * \1, \2, \3    - that many literal bytes follow in the code stream
       * \4, \6        - the POP/PUSH (respectively) codes for CS, DS, ES, SS
       *                 (POP is never used for CS) depending on operand 0
       * \5, \7        - the second byte of POP/PUSH codes for FS, GS, depending
       *                 on operand 0
       * \10, \11, \12 - a literal byte follows in the code stream, to be added
       *                 to the register value of operand 0, 1 or 2
       * \17           - encodes the literal byte 0. (Some compilers don't take
       *                 kindly to a zero byte in the _middle_ of a compile time
       *                 string constant, so I had to put this hack in.)
       * \14, \15, \16 - a signed byte immediate operand, from operand 0, 1 or 2
       * \20, \21, \22 - a byte immediate operand, from operand 0, 1 or 2
       * \24, \25, \26 - an unsigned byte immediate operand, from operand 0, 1 or 2
       * \30, \31, \32 - a word immediate operand, from operand 0, 1 or 2
       * \34, \35, \36 - select between \3[012] and \4[012] depending on 16/32 bit
       *                 assembly mode or the address-size override on the operand
       * \37           - a word constant, from the _segment_ part of operand 0
       * \40, \41, \42 - a long immediate operand, from operand 0, 1 or 2
       * \50, \51, \52 - a byte relative operand, from operand 0, 1 or 2
       * \60, \61, \62 - a word relative operand, from operand 0, 1 or 2
       * \64, \65, \66 - select between \6[012] and \7[012] depending on 16/32 bit
       *                 assembly mode or the address-size override on the operand
       * \70, \71, \72 - a long relative operand, from operand 0, 1 or 2
       * \1ab          - a ModRM, calculated on EA in operand a, with the spare
       *                 field the register value of operand b.
       * \2ab          - a ModRM, calculated on EA in operand a, with the spare
       *                 field equal to digit b.
       * \30x          - might be an 0x67 byte, depending on the address size of
       *                 the memory reference in operand x.
       * \310          - indicates fixed 16-bit address size, i.e. optional 0x67.
       * \311          - indicates fixed 32-bit address size, i.e. optional 0x67.
       * \320          - indicates fixed 16-bit operand size, i.e. optional 0x66.
       * \321          - indicates fixed 32-bit operand size, i.e. optional 0x66.
       * \322          - indicates that this instruction is only valid when the
       *                 operand size is the default (instruction to disassembler,
       *                 generates no code in the assembler)
       * \330          - a literal byte follows in the code stream, to be added
       *                 to the condition code value of the instruction.
       * \340          - reserve <operand 0> bytes of uninitialised storage.
       *                 Operand 0 had better be a segmentless constant.
      }

      var
        currval : longint;
        currsym : tasmsymbol;

        procedure getvalsym(opidx:longint);
        begin
          case oper[opidx]^.typ of
            top_ref :
              begin
                currval:=oper[opidx]^.ref^.offset;
                currsym:=oper[opidx]^.ref^.symbol;
              end;
            top_const :
              begin
                currval:=longint(oper[opidx]^.val);
                currsym:=nil;
              end;
            top_symbol :
              begin
                currval:=oper[opidx]^.symofs;
                currsym:=oper[opidx]^.sym;
              end;
            else
              Message(asmw_e_immediate_or_reference_expected);
          end;
        end;

      const
        CondVal:array[TAsmCond] of byte=($0,
         $7, $3, $2, $6, $2, $4, $F, $D, $C, $E, $6, $2,
         $3, $7, $3, $5, $E, $C, $D, $F, $1, $B, $9, $5,
         $0, $A, $A, $B, $8, $4);
      var
        c : byte;
        pb,
        codes : pchar;
        bytes : array[0..3] of byte;
        rfield,
        data,s,opidx : longint;
        ea_data : ea;
      begin
{$ifdef EXTDEBUG}
        { safety check }
        if sec.sects[sec.currsec].datasize<>insoffset then
         internalerror(200130121);
{$endif EXTDEBUG}
        { load data to write }
        codes:=insentry^.code;
        { Force word push/pop for registers }
        if (opsize=S_W) and ((codes[0]=#4) or (codes[0]=#6) or
            ((codes[0]=#1) and ((codes[2]=#5) or (codes[2]=#7)))) then
          begin
            bytes[0]:=$66;
            sec.writebytes(bytes,1);
          end;
        repeat
          c:=ord(codes^);
          inc(codes);
          case c of
            0 :
              break;
            1,2,3 :
              begin
                sec.writebytes(codes^,c);
                inc(codes,c);
              end;
            4,6 :
              begin
                case oper[0]^.reg of
                  NR_CS:
                    bytes[0]:=$e;
                  NR_NO,
                  NR_DS:
                    bytes[0]:=$1e;
                  NR_ES:
                    bytes[0]:=$6;
                  NR_SS:
                    bytes[0]:=$16;
                  else
                    internalerror(777004);
                end;
                if c=4 then
                  inc(bytes[0]);
                sec.writebytes(bytes,1);
              end;
            5,7 :
              begin
                case oper[0]^.reg of
                  NR_FS:
                    bytes[0]:=$a0;
                  NR_GS:
                    bytes[0]:=$a8;
                  else
                    internalerror(777005);
                end;
                if c=5 then
                  inc(bytes[0]);
                sec.writebytes(bytes,1);
              end;
            8,9,10 :
              begin
                bytes[0]:=ord(codes^)+regval(oper[c-8]^.reg);
                inc(codes);
                sec.writebytes(bytes,1);
              end;
            15 :
              begin
                bytes[0]:=0;
                sec.writebytes(bytes,1);
              end;
            12,13,14 :
              begin
                getvalsym(c-12);
                if (currval<-128) or (currval>127) then
                 Message2(asmw_e_value_exceeds_bounds,'signed byte',tostr(currval));
                if assigned(currsym) then
                  sec.writereloc(currval,1,currsym,RELOC_ABSOLUTE)
                else
                  sec.writebytes(currval,1);
              end;
            16,17,18 :
              begin
                getvalsym(c-16);
                if (currval<-256) or (currval>255) then
                 Message2(asmw_e_value_exceeds_bounds,'byte',tostr(currval));
                if assigned(currsym) then
                 sec.writereloc(currval,1,currsym,RELOC_ABSOLUTE)
                else
                 sec.writebytes(currval,1);
              end;
            20,21,22 :
              begin
                getvalsym(c-20);
                if (currval<0) or (currval>255) then
                 Message2(asmw_e_value_exceeds_bounds,'unsigned byte',tostr(currval));
                if assigned(currsym) then
                 sec.writereloc(currval,1,currsym,RELOC_ABSOLUTE)
                else
                 sec.writebytes(currval,1);
              end;
            24,25,26 :
              begin
                getvalsym(c-24);
                if (currval<-65536) or (currval>65535) then
                 Message2(asmw_e_value_exceeds_bounds,'word',tostr(currval));
                if assigned(currsym) then
                 sec.writereloc(currval,2,currsym,RELOC_ABSOLUTE)
                else
                 sec.writebytes(currval,2);
              end;
            28,29,30 :
              begin
                getvalsym(c-28);
                if assigned(currsym) then
                 sec.writereloc(currval,4,currsym,RELOC_ABSOLUTE)
                else
                 sec.writebytes(currval,4);
              end;
            32,33,34 :
              begin
                getvalsym(c-32);
                if assigned(currsym) then
                 sec.writereloc(currval,4,currsym,RELOC_ABSOLUTE)
                else
                 sec.writebytes(currval,4);
              end;
            40,41,42 :
              begin
                getvalsym(c-40);
                data:=currval-insend;
                if assigned(currsym) then
                 inc(data,currsym.address);
                if (data>127) or (data<-128) then
                 Message1(asmw_e_short_jmp_out_of_range,tostr(data));
                sec.writebytes(data,1);
              end;
            52,53,54 :
              begin
                getvalsym(c-52);
                if assigned(currsym) then
                 sec.writereloc(currval,4,currsym,RELOC_RELATIVE)
                else
                 sec.writereloc(currval-insend,4,nil,RELOC_ABSOLUTE)
              end;
            56,57,58 :
              begin
                getvalsym(c-56);
                if assigned(currsym) then
                 sec.writereloc(currval,4,currsym,RELOC_RELATIVE)
                else
                 sec.writereloc(currval-insend,4,nil,RELOC_ABSOLUTE)
              end;
            192,193,194 :
              begin
                if NeedAddrPrefix(c-192) then
                 begin
                   bytes[0]:=$67;
                   sec.writebytes(bytes,1);
                 end;
              end;
            200 :
              begin
                bytes[0]:=$67;
                sec.writebytes(bytes,1);
              end;
            208 :
              begin
                bytes[0]:=$66;
                sec.writebytes(bytes,1);
              end;
            216 :
              begin
                bytes[0]:=ord(codes^)+condval[condition];
                inc(codes);
                sec.writebytes(bytes,1);
              end;
            201,
            202,
            209,
            210,
            217,218,219 :
              begin
                { these are dissambler hints or 32 bit prefixes which
                  are not needed }
              end;
            31,
            48,49,50,
            224,225,226 :
              begin
                InternalError(777006);
              end
            else
              begin
                if (c>=64) and (c<=191) then
                 begin
                   if (c<127) then
                    begin
                      if (oper[c and 7]^.typ=top_reg) then
                        rfield:=regval(oper[c and 7]^.reg)
                      else
                        rfield:=regval(oper[c and 7]^.ref^.base);
                    end
                   else
                    rfield:=c and 7;
                   opidx:=(c shr 3) and 7;
                   if not process_ea(oper[opidx]^,ea_data,rfield) then
                    Message(asmw_e_invalid_effective_address);

                   pb:=@bytes;
                   pb^:=chr(ea_data.modrm);
                   inc(pb);
                   if ea_data.sib_present then
                    begin
                      pb^:=chr(ea_data.sib);
                      inc(pb);
                    end;

                   s:=pb-pchar(@bytes);
                   sec.writebytes(bytes,s);

                   case ea_data.bytes of
                     0 : ;
                     1 :
                       begin
                         if (oper[opidx]^.ot and OT_MEMORY)=OT_MEMORY then
                          sec.writereloc(oper[opidx]^.ref^.offset,1,oper[opidx]^.ref^.symbol,RELOC_ABSOLUTE)
                         else
                          begin
                            bytes[0]:=oper[opidx]^.ref^.offset;
                            sec.writebytes(bytes,1);
                          end;
                         inc(s);
                       end;
                     2,4 :
                       begin
                         sec.writereloc(oper[opidx]^.ref^.offset,ea_data.bytes,
                           oper[opidx]^.ref^.symbol,RELOC_ABSOLUTE);
                         inc(s,ea_data.bytes);
                       end;
                   end;
                 end
                else
                 InternalError(777007);
              end;
          end;
        until false;
      end;
{$endif NOAG386BIN}

    function Taicpu.is_nop:boolean;

    begin
      {We do not check the number of operands; we assume that nobody constructs
       a mov or xchg instruction with less than 2 operands. (DM)}
      is_nop:=(opcode=A_NOP) or
              (opcode=A_MOV) and (oper[0]^.typ=top_reg) and (oper[1]^.typ=top_reg) and (oper[0]^.reg=oper[1]^.reg) or
              (opcode=A_XCHG) and (oper[0]^.typ=top_reg) and (oper[1]^.typ=top_reg) and (oper[0]^.reg=oper[1]^.reg);
    end;

    function Taicpu.is_move:boolean;

    begin
      {We do not check the number of operands; we assume that nobody constructs
       a mov, movzx or movsx instruction with less than 2 operands. Note that
       a move between a reference and a register is not a move that is of
       interrest to the register allocation, therefore we only return true
       for a move between two registers. (DM)}
      is_move:=((opcode=A_MOV) or (opcode=A_MOVZX) or (opcode=A_MOVSX)) and
        ((oper[0]^.typ=top_reg) and (oper[1]^.typ=top_reg));
    end;


    function Taicpu.spill_registers(list:Taasmoutput;
                                    rgget:Trggetproc;
                                    rgunget:Trgungetproc;
                                    const r:Tsuperregisterset;
                                    var unusedregsint:Tsuperregisterset;
                                    const spilltemplist:Tspill_temp_list):boolean;

    {Spill the registers in r in this instruction. Returns true if any help
     registers are used. This procedure has become one big hack party, because
     of the huge amount of situations you can have. The irregularity of the i386
     instruction set doesn't help either. (DM)}


    var i:byte;
        supreg:Tsuperregister;
        subreg:Tsubregister;
        helpreg:Tregister;
        helpins:Taicpu;
        op:Tasmop;
        hopsize:Topsize;
        pos:Tai;

    begin
      {Situation examples are in intel notation, so operand order:
       mov    eax       ,    ebx
              ^^^            ^^^
              oper[1]        oper[0]
      (DM)}
      spill_registers:=false;
      case ops of
        1:
          begin
            if (oper[0]^.typ=top_reg) and
               (getregtype(oper[0]^.reg)=R_INTREGISTER) then
              begin
                supreg:=getsupreg(oper[0]^.reg);
                if supregset_in(r,supreg) then
                  begin
                    {Situation example:
                     push r20d              ; r20d must be spilled into [ebp-12]

                    Change into:
                     push [ebp-12]          ; Replace register by reference }
{                    hopsize:=reg2opsize(oper[0].reg);}
                    oper[0]^.typ:=top_ref;
                    new(oper[0]^.ref);
                    oper[0]^.ref^:=spilltemplist[supreg];
{                    oper[0]^.ref^.size:=hopsize;}
                  end;
              end;
            if oper[0]^.typ=top_ref then
              begin
                supreg:=getsupreg(oper[0]^.ref^.base);
                if supregset_in(r,supreg) then
                  begin
                    {Situation example:
                     push [r21d+4*r22d]        ; r21d must be spilled into [ebp-12]

                     Change into:

                     mov r23d,[ebp-12]         ; Use a help register
                     push [r23d+4*r22d]        ; Replace register by helpregister }
                    subreg:=getsubreg(oper[0]^.ref^.base);
                    if oper[0]^.ref^.index=NR_NO then
                      pos:=Tai(previous)
                    else
                      pos:=get_insert_pos(Tai(previous),getsupreg(oper[0]^.ref^.index),RS_INVALID,RS_INVALID,unusedregsint);
                    rgget(list,pos,subreg,helpreg);
                    spill_registers:=true;
                    helpins:=Taicpu.op_ref_reg(A_MOV,reg2opsize(oper[0]^.ref^.base),spilltemplist[supreg],helpreg);
                    if pos=nil then
                      list.insertafter(helpins,list.first)
                    else
                      list.insertafter(helpins,pos.next);
                    rgunget(list,helpins,helpreg);
                    forward_allocation(Tai(helpins.next),unusedregsint);
                    oper[0]^.ref^.base:=helpreg;
                  end;
                supreg:=getsupreg(oper[0]^.ref^.index);
                if supregset_in(r,supreg) then
                  begin
                    {Situation example:
                     push [r21d+4*r22d]        ; r22d must be spilled into [ebp-12]

                     Change into:

                     mov r23d,[ebp-12]         ; Use a help register
                     push [r21d+4*r23d]        ; Replace register by helpregister }
                    subreg:=getsubreg(oper[0]^.ref^.index);
                    if oper[0]^.ref^.base=NR_NO then
                      pos:=Tai(previous)
                    else
                      pos:=get_insert_pos(Tai(previous),getsupreg(oper[0]^.ref^.base),RS_INVALID,RS_INVALID,unusedregsint);
                    rgget(list,pos,subreg,helpreg);
                    spill_registers:=true;
                    helpins:=Taicpu.op_ref_reg(A_MOV,reg2opsize(oper[0]^.ref^.index),spilltemplist[supreg],helpreg);
                    if pos=nil then
                      list.insertafter(helpins,list.first)
                    else
                      list.insertafter(helpins,pos.next);
                    rgunget(list,helpins,helpreg);
                    forward_allocation(Tai(helpins.next),unusedregsint);
                    oper[0]^.ref^.index:=helpreg;
                  end;
                end;
          end;
        2:
          begin
            { First spill the registers from the references. This is
              required because the reference can be moved from this instruction
              to a MOV instruction when spilling of the register operand is done }
            for i:=0 to 1 do
              if oper[i]^.typ=top_ref then
                begin
                  supreg:=getsupreg(oper[i]^.ref^.base);
                  if supregset_in(r,supreg) then
                    begin
                      {Situation example:
                       add r20d,[r21d+4*r22d]    ; r21d must be spilled into [ebp-12]

                       Change into:

                       mov r23d,[ebp-12]         ; Use a help register
                       add r20d,[r23d+4*r22d]    ; Replace register by helpregister }
                      subreg:=getsubreg(oper[i]^.ref^.base);
                      if i=1 then
                        pos:=get_insert_pos(Tai(previous),getsupreg(oper[i]^.ref^.index),getsupreg(oper[0]^.reg),
                                            RS_INVALID,unusedregsint)
                      else
                        pos:=get_insert_pos(Tai(previous),getsupreg(oper[i]^.ref^.index),RS_INVALID,RS_INVALID,unusedregsint);
                      rgget(list,pos,subreg,helpreg);
                      spill_registers:=true;
                      helpins:=Taicpu.op_ref_reg(A_MOV,reg2opsize(oper[i]^.ref^.base),spilltemplist[supreg],helpreg);
                      if pos=nil then
                        list.insertafter(helpins,list.first)
                      else
                        list.insertafter(helpins,pos.next);
                      oper[i]^.ref^.base:=helpreg;
                      rgunget(list,helpins,helpreg);
                      forward_allocation(Tai(helpins.next),unusedregsint);
                  end;
                  supreg:=getsupreg(oper[i]^.ref^.index);
                  if supregset_in(r,supreg) then
                    begin
                      {Situation example:
                       add r20d,[r21d+4*r22d]    ; r22d must be spilled into [ebp-12]

                       Change into:

                       mov r23d,[ebp-12]         ; Use a help register
                       add r20d,[r21d+4*r23d]    ; Replace register by helpregister }
                      subreg:=getsubreg(oper[i]^.ref^.index);
                      if i=1 then
                        pos:=get_insert_pos(Tai(previous),getsupreg(oper[i]^.ref^.base),getsupreg(oper[0]^.reg),
                                            RS_INVALID,unusedregsint)
                      else
                        pos:=get_insert_pos(Tai(previous),getsupreg(oper[i]^.ref^.base),RS_INVALID,RS_INVALID,unusedregsint);
                      rgget(list,pos,subreg,helpreg);
                      spill_registers:=true;
                      helpins:=Taicpu.op_ref_reg(A_MOV,reg2opsize(oper[i]^.ref^.index),spilltemplist[supreg],helpreg);
                      if pos=nil then
                        list.insertafter(helpins,list.first)
                      else
                        list.insertafter(helpins,pos.next);
                      oper[i]^.ref^.index:=helpreg;
                      rgunget(list,helpins,helpreg);
                      forward_allocation(Tai(helpins.next),unusedregsint);
                    end;
                end;
            if (oper[0]^.typ=top_reg) and
               (getregtype(oper[0]^.reg)=R_INTREGISTER) then
              begin
                supreg:=getsupreg(oper[0]^.reg);
                subreg:=getsubreg(oper[0]^.reg);
                if supregset_in(r,supreg) then
                  if oper[1]^.typ=top_ref then
                    begin
                      {Situation example:
                       add [r20d],r21d      ; r21d must be spilled into [ebp-12]

                       Change into:

                       mov r22d,[ebp-12]    ; Use a help register
                       add [r20d],r22d      ; Replace register by helpregister }
                      pos:=get_insert_pos(Tai(previous),getsupreg(oper[0]^.reg),
                                          getsupreg(oper[1]^.ref^.base),getsupreg(oper[1]^.ref^.index),
                                          unusedregsint);
                      rgget(list,pos,subreg,helpreg);
                      spill_registers:=true;
                      helpins:=Taicpu.op_ref_reg(A_MOV,reg2opsize(oper[0]^.reg),spilltemplist[supreg],helpreg);
                      if pos=nil then
                        list.insertafter(helpins,list.first)
                      else
                        list.insertafter(helpins,pos.next);
                      oper[0]^.reg:=helpreg;
                      rgunget(list,helpins,helpreg);
                      forward_allocation(Tai(helpins.next),unusedregsint);
                    end
                  else
                    begin
                      {Situation example:
                       add r20d,r21d        ; r21d must be spilled into [ebp-12]

                       Change into:

                       add r20d,[ebp-12]    ; Replace register by reference }
                      oper[0]^.typ:=top_ref;
                      new(oper[0]^.ref);
                      oper[0]^.ref^:=spilltemplist[supreg];
                    end;
              end;
            if (oper[1]^.typ=top_reg) and
               (getregtype(oper[1]^.reg)=R_INTREGISTER) then
              begin
                supreg:=getsupreg(oper[1]^.reg);
                subreg:=getsubreg(oper[1]^.reg);
                if supregset_in(r,supreg) then
                  begin
                    if oper[0]^.typ=top_ref then
                      begin
                        {Situation example:
                         add r20d,[r21d]      ; r20d must be spilled into [ebp-12]

                         Change into:

                         mov r22d,[r21d]      ; Use a help register
                         add [ebp-12],r22d    ; Replace register by helpregister }
                        pos:=get_insert_pos(Tai(previous),getsupreg(oper[0]^.ref^.base),
                                            getsupreg(oper[0]^.ref^.index),RS_INVALID,unusedregsint);
                        rgget(list,pos,subreg,helpreg);
                        spill_registers:=true;
                        op:=A_MOV;
                        hopsize:=opsize;  {Save old value...}
                        if (opcode=A_MOVZX) or (opcode=A_MOVSX) or (opcode=A_LEA) then
                          begin
                            {Because 'movzx memory,register' does not exist...}
                            op:=opcode;
                            opcode:=A_MOV;
                            opsize:=reg2opsize(oper[1]^.reg);
                          end;
                        helpins:=Taicpu.op_ref_reg(op,hopsize,oper[0]^.ref^,helpreg);
                        if pos=nil then
                          list.insertafter(helpins,list.first)
                        else
                          list.insertafter(helpins,pos.next);
                        dispose(oper[0]^.ref);
                        oper[0]^.typ:=top_reg;
                        oper[0]^.reg:=helpreg;
                        oper[1]^.typ:=top_ref;
                        new(oper[1]^.ref);
                        oper[1]^.ref^:=spilltemplist[supreg];
                        rgunget(list,helpins,helpreg);
                        forward_allocation(Tai(helpins.next),unusedregsint);
                      end
                    else
                      begin
                        {Situation example:
                         add r20d,r21d        ; r20d must be spilled into [ebp-12]

                         Change into:

                         add [ebp-12],r21d    ; Replace register by reference }
                        if (opcode=A_MOVZX) or (opcode=A_MOVSX) then
                          begin
                            {Because 'movzx memory,register' does not exist...}
                            spill_registers:=true;
                            op:=opcode;
                            hopsize:=opsize;
                            opcode:=A_MOV;
                            opsize:=reg2opsize(oper[1]^.reg);
                            pos:=get_insert_pos(Tai(previous),getsupreg(oper[0]^.reg),RS_INVALID,RS_INVALID,unusedregsint);
                            rgget(list,pos,subreg,helpreg);
                            helpins:=Taicpu.op_reg_reg(op,hopsize,oper[0]^.reg,helpreg);
                            if pos=nil then
                              list.insertafter(helpins,list.first)
                            else
                              list.insertafter(helpins,pos.next);
                            oper[0]^.reg:=helpreg;
                            rgunget(list,helpins,helpreg);
                            forward_allocation(Tai(helpins.next),unusedregsint);
                          end;
                        oper[1]^.typ:=top_ref;
                        new(oper[1]^.ref);
                        oper[1]^.ref^:=spilltemplist[supreg];
                      end;
                  end;
              end;

            { The i386 instruction set never gets boring...
              some opcodes do not support a memory location as destination }
            if (oper[1]^.typ=top_ref) and
               (
                (oper[0]^.typ=top_const) or
                ((oper[0]^.typ=top_reg) and
                 (getregtype(oper[0]^.reg)=R_INTREGISTER))
               ) then
              begin
                case opcode of
                  A_IMUL :
                    begin
                      {Yikes! We just changed the destination register into
                       a memory location above here.

                       Situation examples:

                       imul [ebp-12],r21d    ; We need a help register
                       imul [ebp-12],<const> ; We need a help register

                       Change into:

                       mov r22d,[ebp-12]    ; Use a help instruction (only for IMUL)
                       imul r22d,r21d       ; Replace reference by helpregister
                       mov [ebp-12],r22d    ; Use another help instruction}
                      rgget(list,Tai(previous),subreg,helpreg);
                      spill_registers:=true;
                      {First help instruction.}
                      helpins:=Taicpu.op_ref_reg(A_MOV,opsize,oper[1]^.ref^,helpreg);
                      if previous=nil then
                        list.insert(helpins)
                      else
                        list.insertafter(helpins,previous);
                      {Second help instruction.}
                      helpins:=Taicpu.op_reg_ref(A_MOV,opsize,helpreg,oper[1]^.ref^);
                      dispose(oper[1]^.ref);
                      oper[1]^.typ:=top_reg;
                      oper[1]^.reg:=helpreg;
                      list.insertafter(helpins,self);
                      rgunget(list,self,helpreg);
                    end;
                end;
              end;

            { The i386 instruction set never gets boring...
              some opcodes do not support a memory location as source }
            if (oper[0]^.typ=top_ref) and
               (oper[1]^.typ=top_reg) and
               (getregtype(oper[1]^.reg)=R_INTREGISTER) then
              begin
                case opcode of
                  A_BT,A_BTS,
                  A_BTC,A_BTR :
                    begin
                      {Yikes! We just changed the source register into
                       a memory location above here.

                       Situation example:

                       bt  r21d,[ebp-12]   ; We need a help register

                       Change into:

                       mov r22d,[ebp-12]    ; Use a help instruction (only for IMUL)
                       bt  r21d,r22d        ; Replace reference by helpregister}
                      rgget(list,Tai(previous),subreg,helpreg);
                      spill_registers:=true;
                      {First help instruction.}
                      helpins:=Taicpu.op_ref_reg(A_MOV,opsize,oper[0]^.ref^,helpreg);
                      if previous=nil then
                        list.insert(helpins)
                      else
                        list.insertafter(helpins,previous);
                      dispose(oper[0]^.ref);
                      oper[0]^.typ:=top_reg;
                      oper[0]^.reg:=helpreg;
                      rgunget(list,helpins,helpreg);
                    end;
                end;
              end;
          end;
        3:
          begin
            {$warning todo!!}
          end;
      end;
    end;


{*****************************************************************************
                              Instruction table
*****************************************************************************}

    procedure BuildInsTabCache;
{$ifndef NOAG386BIN}
      var
        i : longint;
{$endif}
      begin
{$ifndef NOAG386BIN}
        new(instabcache);
        FillChar(instabcache^,sizeof(tinstabcache),$ff);
        i:=0;
        while (i<InsTabEntries) do
         begin
           if InsTabCache^[InsTab[i].OPcode]=-1 then
            InsTabCache^[InsTab[i].OPcode]:=i;
           inc(i);
         end;
{$endif NOAG386BIN}
      end;


    procedure InitAsm;
      begin
{$ifndef NOAG386BIN}
        if not assigned(instabcache) then
          BuildInsTabCache;
{$endif NOAG386BIN}
      end;


    procedure DoneAsm;
      begin
{$ifndef NOAG386BIN}
        if assigned(instabcache) then
        begin
          dispose(instabcache);
          instabcache:=nil;
        end;
{$endif NOAG386BIN}
      end;



end.
{
  $Log$
  Revision 1.35  2003-10-23 14:44:07  peter
    * splitted buildderef and buildderefimpl to fix interface crc
      calculation

  Revision 1.34  2003/10/22 20:40:00  peter
    * write derefdata in a separate ppu entry

  Revision 1.33  2003/10/21 15:15:36  peter
    * taicpu_abstract.oper[] changed to pointers

  Revision 1.32  2003/10/17 14:38:32  peter
    * 64k registers supported
    * fixed some memory leaks

  Revision 1.31  2003/10/09 21:31:37  daniel
    * Register allocator splitted, ans abstract now

  Revision 1.30  2003/10/01 20:34:50  peter
    * procinfo unit contains tprocinfo
    * cginfo renamed to cgbase
    * moved cgmessage to verbose
    * fixed ppc and sparc compiles

  Revision 1.29  2003/09/29 20:58:56  peter
    * optimized releasing of registers

  Revision 1.28  2003/09/28 21:49:30  peter
    * fixed invalid opcode handling in spill registers

  Revision 1.27  2003/09/28 13:37:07  peter
    * give error for wrong register number

  Revision 1.26  2003/09/24 21:15:49  florian
    * fixed make cycle

  Revision 1.25  2003/09/24 17:12:36  florian
    * x86-64 adaptions

  Revision 1.24  2003/09/23 17:56:06  peter
    * locals and paras are allocated in the code generation
    * tvarsym.localloc contains the location of para/local when
      generating code for the current procedure

  Revision 1.23  2003/09/14 14:22:51  daniel
    * Fixed incorrect movzx spilling

  Revision 1.22  2003/09/12 20:25:17  daniel
    * Add BTR to destination memory location check in spilling

  Revision 1.21  2003/09/10 19:14:31  daniel
    * Failed attempt to restore broken fastspill functionality

  Revision 1.20  2003/09/10 11:23:09  marco
   * fix from peter for bts reg32,mem32 problem

  Revision 1.19  2003/09/09 12:54:45  florian
    * x86 instruction table updated to nasm 0.98.37:
        - sse3 aka prescott support
        - small fixes

  Revision 1.18  2003/09/07 22:09:35  peter
    * preparations for different default calling conventions
    * various RA fixes

  Revision 1.17  2003/09/03 15:55:02  peter
    * NEWRA branch merged

  Revision 1.16.2.4  2003/08/31 15:46:26  peter
    * more updates for tregister

  Revision 1.16.2.3  2003/08/29 17:29:00  peter
    * next batch of updates

  Revision 1.16.2.2  2003/08/28 18:35:08  peter
    * tregister changed to cardinal

  Revision 1.16.2.1  2003/08/27 19:55:54  peter
    * first tregister patch

  Revision 1.16  2003/08/21 17:20:19  peter
    * first spill the registers of top_ref before spilling top_reg

  Revision 1.15  2003/08/21 14:48:36  peter
    * fix reg-supreg range check error

  Revision 1.14  2003/08/20 16:52:01  daniel
    * Some old register convention code removed
    * A few changes to eliminate a few lines of code

  Revision 1.13  2003/08/20 09:07:00  daniel
    * New register coding now mandatory, some more convert_registers calls
      removed.

  Revision 1.12  2003/08/20 07:48:04  daniel
    * Made internal assembler use new register coding

  Revision 1.11  2003/08/19 13:58:33  daniel
    * Corrected a comment.

  Revision 1.10  2003/08/15 14:44:20  daniel
    * Fixed newra compilation

  Revision 1.9  2003/08/11 21:18:20  peter
    * start of sparc support for newra

  Revision 1.8  2003/08/09 18:56:54  daniel
    * cs_regalloc renamed to cs_regvars to avoid confusion with register
      allocator
    * Some preventive changes to i386 spillinh code

  Revision 1.7  2003/07/06 15:31:21  daniel
    * Fixed register allocator. *Lots* of fixes.

  Revision 1.6  2003/06/14 14:53:50  jonas
    * fixed newra cycle for x86
    * added constants for indicating source and destination operands of the
      "move reg,reg" instruction to aasmcpu (and use those in rgobj)

  Revision 1.5  2003/06/03 13:01:59  daniel
    * Register allocator finished

  Revision 1.4  2003/05/30 23:57:08  peter
    * more sparc cleanup
    * accumulator removed, splitted in function_return_reg (called) and
      function_result_reg (caller)

  Revision 1.3  2003/05/22 21:33:31  peter
    * removed some unit dependencies

  Revision 1.2  2002/04/25 16:12:09  florian
    * fixed more problems with cpubase and x86-64

  Revision 1.1  2003/04/25 12:43:40  florian
    * merged i386/aasmcpu and x86_64/aasmcpu to x86/aasmcpu

  Revision 1.18  2003/04/25 12:04:31  florian
    * merged agx64att and ag386att to x86/agx86att

  Revision 1.17  2003/04/22 14:33:38  peter
    * removed some notes/hints

  Revision 1.16  2003/04/22 10:09:35  daniel
    + Implemented the actual register allocator
    + Scratch registers unavailable when new register allocator used
    + maybe_save/maybe_restore unavailable when new register allocator used

  Revision 1.15  2003/03/26 12:50:54  armin
  * avoid problems with the ide in init/dome

  Revision 1.14  2003/03/08 08:59:07  daniel
    + $define newra will enable new register allocator
    + getregisterint will return imaginary registers with $newra
    + -sr switch added, will skip register allocation so you can see
      the direct output of the code generator before register allocation

  Revision 1.13  2003/02/25 07:41:54  daniel
    * Properly fixed reversed operands bug

  Revision 1.12  2003/02/19 22:00:15  daniel
    * Code generator converted to new register notation
    - Horribily outdated todo.txt removed

  Revision 1.11  2003/01/09 20:40:59  daniel
    * Converted some code in cgx86.pas to new register numbering

  Revision 1.10  2003/01/08 18:43:57  daniel
   * Tregister changed into a record

  Revision 1.9  2003/01/05 13:36:53  florian
    * x86-64 compiles
    + very basic support for float128 type (x86-64 only)

  Revision 1.8  2002/11/17 16:31:58  carl
    * memory optimization (3-4%) : cleanup of tai fields,
       cleanup of tdef and tsym fields.
    * make it work for m68k

  Revision 1.7  2002/11/15 01:58:54  peter
    * merged changes from 1.0.7 up to 04-11
      - -V option for generating bug report tracing
      - more tracing for option parsing
      - errors for cdecl and high()
      - win32 import stabs
      - win32 records<=8 are returned in eax:edx (turned off by default)
      - heaptrc update
      - more info for temp management in .s file with EXTDEBUG

  Revision 1.6  2002/10/31 13:28:32  pierre
   * correct last wrong fix for tw2158

  Revision 1.5  2002/10/30 17:10:00  pierre
   * merge of fix for tw2158 bug

  Revision 1.4  2002/08/15 19:10:36  peter
    * first things tai,tnode storing in ppu

  Revision 1.3  2002/08/13 18:01:52  carl
    * rename swatoperands to swapoperands
    + m68k first compilable version (still needs a lot of testing):
        assembler generator, system information , inline
        assembler reader.

  Revision 1.2  2002/07/20 11:57:59  florian
    * types.pas renamed to defbase.pas because D6 contains a types
      unit so this would conflicts if D6 programms are compiled
    + Willamette/SSE2 instructions to assembler added

  Revision 1.1  2002/07/01 18:46:29  peter
    * internal linker
    * reorganized aasm layer

}