freepascal.compiler/compiler/i386/n386cal.pas

{
    Copyright (c) 1998-2002 by Florian Klaempfl

    Generate i386 assembler for in call nodes

    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 n386cal;

{$i fpcdefs.inc}

interface

{ $define AnsiStrRef}

    uses
      nx86cal,ncal;

    type
       ti386callnode = class(tx86callnode)
       protected
          procedure gen_syscall_para(para: tcallparanode); override;
          procedure pop_parasize(pop_size:longint);override;
          procedure extra_interrupt_code;override;
       public
         procedure do_syscall;override;
       end;


implementation

    uses
      globtype,systems,
      cutils,verbose,globals,
      cgbase,cgutils,
      cpubase,paramgr,
      aasmtai,aasmdata,aasmcpu,
      nbas,nmem,nld,ncnv,
      symdef,symsym,symcpu,
      cga,cgobj,cpuinfo;


{*****************************************************************************
                             TI386CALLNODE
*****************************************************************************}


    procedure ti386callnode.do_syscall;
      var
        tmpref: treference;
      begin
        case target_info.system of
          system_i386_aros:
            begin
              // one syscall convention for AROS
              current_asmdata.CurrAsmList.concat(tai_comment.create(strpnew('AROS SysCall')));
              reference_reset(tmpref,sizeof(pint));
              { re-read the libbase pushed first on the stack, instead of just trusting the
                mangledname will work. this is important for example for threadvar libbases.
                and this way they also don't need to be resolved twice then. (KB) }
              tmpref.base:=NR_ESP;
              tmpref.offset:=pushedparasize-sizeof(pint);
              cg.getcpuregister(current_asmdata.CurrAsmList,NR_EAX);
              cg.a_load_ref_reg(current_asmdata.CurrAsmList,OS_ADDR,OS_ADDR,tmpref,NR_EAX);
              reference_reset_base(tmpref,NR_EAX,-tprocdef(procdefinition).extnumber,sizeof(pint));
              cg.a_load_ref_reg(current_asmdata.CurrAsmList,OS_ADDR,OS_ADDR,tmpref,NR_EAX);
              cg.a_call_reg(current_asmdata.CurrAsmList,NR_EAX);
              cg.ungetcpuregister(current_asmdata.CurrAsmList,NR_EAX);
            end;
          else
            internalerror(2014081801);
        end;
      end;


    procedure ti386callnode.gen_syscall_para(para: tcallparanode);
      begin
        { lib parameter has no special type but proccalloptions must be a syscall }
        para.left:=cloadnode.create(tcpuprocdef(procdefinition).libsym,tcpuprocdef(procdefinition).libsym.owner);
      end;

    procedure ti386callnode.extra_interrupt_code;
      begin
        if not(target_info.system in [system_i386_darwin,system_i386_iphonesim,system_i386_android]) then
          begin
            emit_none(A_PUSHF,S_L);
            emit_reg(A_PUSH,S_L,NR_CS);
          end;
      end;


    procedure ti386callnode.pop_parasize(pop_size:longint);
      var
        hreg : tregister;
      begin
        if (paramanager.use_fixed_stack) then
          begin
            { very weird: in this case the callee does a "ret $4" and the }
            { caller immediately a "subl $4,%esp". Possibly this is for   }
            { use_fixed_stack code to be able to transparently call       }
            { old-style code (JM)                                         }
            dec(pop_size,pushedparasize);
            if (pop_size < 0) then
              current_asmdata.CurrAsmList.concat(taicpu.op_const_reg(A_SUB,S_L,-pop_size,NR_ESP));
            exit;
          end;

        { on win32, the caller is responsible for removing the funcret     }
        { pointer from the stack, unlike on Linux. Don't know about        }
        { elsewhere (except Darwin, handled above), but since the default  }
        { was "callee removes funcret pointer from stack" until now, we'll }
        { keep that default for everyone else (ncgcal decreases popsize by }
        { sizeof(aint) in case of ret_in_param())                          }
        { This is only correct if the hidden funcret parameter
          is not passed as a register.
          As it is inserted in parast after all other hidden parameters,
          it is always the first parameter (apart from hidden parentfp,
          but this one is never put into a register (vs_nonregable set)
          so funcret is always in EAX for register calling }
        if ((target_info.system = system_i386_win32) and
            not (target_info.abi=abi_old_win32_gnu)) and
            paramanager.ret_in_param(procdefinition.returndef,procdefinition) and
            not ((procdefinition.proccalloption=pocall_register) or
                 ((procdefinition.proccalloption=pocall_internproc) and
                  (pocall_default=pocall_register))) then
          inc(pop_size,sizeof(aint));

        { better than an add on all processors }
        if pop_size=4 then
          begin
            hreg:=cg.getintregister(current_asmdata.CurrAsmList,OS_INT);
            current_asmdata.CurrAsmList.concat(taicpu.op_reg(A_POP,S_L,hreg));
          end
        { the pentium has two pipes and pop reg is pairable }
        { but the registers must be different!        }
        else
          if (pop_size=8) and
             not(cs_opt_size in current_settings.optimizerswitches) and
             (current_settings.optimizecputype=cpu_Pentium) then
            begin
               hreg:=cg.getintregister(current_asmdata.CurrAsmList,OS_INT);
               current_asmdata.CurrAsmList.concat(taicpu.op_reg(A_POP,S_L,hreg));
               hreg:=cg.getintregister(current_asmdata.CurrAsmList,OS_INT);
               current_asmdata.CurrAsmList.concat(taicpu.op_reg(A_POP,S_L,hreg));
            end
        else
          if pop_size<>0 then
            current_asmdata.CurrAsmList.concat(taicpu.op_const_reg(A_ADD,S_L,pop_size,NR_ESP));
      end;


begin
   ccallnode:=ti386callnode;
end.