AROS: Startupcode for x86_64 with stack extent feature

git-svn-id: trunk@35049 -

rtl/aros/x86_64/prt0.as

@@ -1,6 +1,6 @@
 #
 #   This file is part of the Free Pascal run time library.
-#   Copyright (c) 2015 by Marcus Sackrow
+#   Copyright (c) 2015-2016 by Marcus Sackrow
 #
 #   AROS x86_64 startup code
 #
@@ -14,57 +14,161 @@
 #**********************************************************************}
 
 # AROS startup code
-	.text
-	.align 8
-        .section .aros.startup, "ax"
-        .globl start
-        .globl _start
-	.type _start,@function	
+  .text
+  .align 8
+  .section .aros.startup, "ax"
+  .globl start
+  .globl _start
+  .type _start,@function
 _start:
 start:
 # save registers, suggested by
 # System V Application Binary Interface
 # AMD64 Architecture Processor Support
 # 0.99.6 page 21 Fig. 3.4
-        push	%rbp
-        push	%rbx
-        push	%r12
-        push	%r13
-        push	%r14
-        push	%r15
-        movq	%rdx, _ExecBase
-        movq	%rsp, STKPTR
+  push %rbp
+  push %rbx
+  push %r12
+  push %r13
+  push %r14
+  push %r15
+  movq %rdx, _ExecBase
+  movq %rsp, STKPTR
 # todo: stack change (see i386)
-        callq	PASCALMAIN
-	jmpq	_haltproc
 
-        .globl  _haltproc
-        .type   _haltproc,@function
+# FindTask(nil)
+  movq _ExecBase, %rsi  /* Execbase to rsi */
+  movq $0, %rdi         /* 1. Argument nil */
+  movq -392(%rsi), %rax /* calculate jump address */
+  call *%rax            /* do the call */
+# PTask in %rax -> get data from PTask splower rbx, spupper rcx
+  movq 112(%rax), %rcx
+  movq 104(%rax), %rbx
+  subq %rbx, %rcx
+# check if Stack is big enough
+  cmpl  __stklen, %ecx
+  jl _AllocStack             /* we need a stack */
+  # no stack needed, clear StackAreaPtr jump to Pascal routine
+  xorq  %rax, %rax
+  movq %rax, StackAreaPtr
+  jmp _NoAllocStack
+
+# Alloc a new Stack and swap to it
+_AllocStack:
+  # AllocVec(__stklen, MEMF_ANY)
+  movq _ExecBase, %rdx      /* execbase Execbase is already in %rdx */
+  movq $0, %rsi             /* 2. Argument MEMF_ANY to %rsi */
+  movl __stklen, %edi       /* 1. Argument stklen to %edi */
+  call *-912(%rdx)          /* Do the call */
+  # save the Stack Area
+  movq %rax, StackAreaPtr
+  # Check if we got some memory
+  cmpq $0, %rax
+  je  _exit
+
+  # Setup StackSwapStruct
+  lea StackSwapStruct, %rcx   /* StackSwapStruct in RCX */
+  movq StackAreaPtr, %rax
+  movq %rax,(%rcx)            /* stk_Lower Bottom of the stack */
+  xorq %rbx, %rbx
+  movl __stklen, %ebx         /* get Stacklen */
+  addq %rbx, %rax             /* add stacklen to lower stack pointer */
+  movq %rax, 8(%rcx)          /* Top of the stack */
+  movq %rax, 16(%rcx)         /* Initial stackpointer */
+
+  # NewStackSwap(StackSwapStruct, _initProc, StackSwapArgs)
+  movq _ExecBase, %rcx      /* Execbase to rcx */
+  lea StackSwapArgs, %rdx   /* 3. Argument StackSwapArgument -> rdx */
+  lea _initProc, %rsi       /* 2. Argument FunktionPtr -> rsi */
+  lea StackSwapStruct, %rdi /* 1. Argument StackSwapStruct -> rdi */
+  call *-1072(%rcx)         /* Do the call */
+  jmp _afterMain
+
+_NoAllocStack:
+  call _initProc
+
+_afterMain:
+  # test it StackArea Ptr assigned
+  movq StackAreaPtr,%rax
+  cmpq $0, StackAreaPtr
+  je _exit                 /* its nil -> direkt exit */
+
+  # FreeVec(StackAreaPtr)
+  movq _ExecBase, %rsi     /* ExecBase as last argument %rsi */
+  movq StackAreaPtr, %rdi  /* StackAreaPtr 1 Argument %rdi */
+  call *-920(%rsi)         /* Do the call */
+
+_exit:
+  # set returncode
+  movslq  operatingsystem_result,%rax
+  # get back all registers
+  mov STKPTR, %rsp
+  pop %r15
+  pop %r14
+  pop %r13
+  pop %r12
+  pop %rbx
+  pop %rbp
+  # bye bye
+  ret
+
+_initProc:
+  push %rbp
+  push %rbx
+  push %r12
+  push %r13
+  push %r14
+  push %r15
+  # Save stack pointer
+  movq %rsp,SSTKPTR
+  # call the pascal main function
+  callq PASCALMAIN
+
+  # entry to stop the program
+  .globl  _haltproc
+  .type   _haltproc,@function
 _haltproc:
-	movslq	operatingsystem_result,%rax
-	mov	STKPTR, %rsp
-	pop	%r15
-	pop	%r14
-	pop	%r13
-	pop	%r12
-	pop	%rbx
-	pop	%rbp
-        ret
-
-	.data
-	.globl __data_start
+  # restore the old stackPtr and return
+  movq SSTKPTR,%rsp
+  pop %r15
+  pop %r14
+  pop %r13
+  pop %r12
+  pop %rbx
+  pop %rbp
+  ret
+
+/*----------------------------------------------------*/
+  .data
+  .globl __data_start
 __data_start:
-	.long 0
-	.weak data_start
+  .long 0
+  .weak data_start
         data_start = __data_start
 
 .bss
-		.type	STKPTR,@object
-		.size	STKPTR,8
-		.global	STKPTR
-STKPTR:	.skip	8
-
-		.type	_ExecBase,@object
-		.size	_ExecBase,8
-		.global	_ExecBase
-_ExecBase:	.skip	8
+.type STKPTR,@object
+.size STKPTR,8
+STKPTR: .skip 8
+
+.type SSTKPTR,@object
+.size SSTKPTR,8
+SSTKPTR: .skip 8
+
+.type _ExecBase,@object
+.size _ExecBase,8
+.global _ExecBase
+_ExecBase:  .skip 8
+
+.type StackAreaPtr,@object
+.size StackAreaPtr,8
+StackAreaPtr:  .skip 8
+
+.type StackSwapStruct,@object
+.size StackSwapStruct,24
+StackSwapStruct: .skip 24
+
+.type StackSwapStruct,@object
+.size StackSwapStruct,64
+StackSwapArgs: .skip 64
+