;-----------------------------------------------------------------------------
; chkstk.asm - check stack upon procedure entry
; Adapted from Visual Studio C runtime library
; Portions Copyright (c) Microsoft Corporation. All rights reserved.
;-----------------------------------------------------------------------------
.model flat
.code
PAGESIZE equ 4096
__chkstk proc public
__alloca_probe = __chkstk
public __alloca_probe
cmp eax, PAGESIZE ; more than one page?
jae short probesetup ; yes, go setup probe loop
; no
neg eax ; compute new stack pointer in eax
add eax,esp
add eax,4
test dword ptr [eax],eax ; probe it
xchg eax,esp
mov eax,dword ptr [eax]
push eax
ret
probesetup:
push ecx ; save ecx
lea ecx,[esp] + 8 ; compute new stack pointer in ecx
; correct for return address and
; saved ecx
probepages:
sub ecx,PAGESIZE ; yes, move down a page
sub eax,PAGESIZE ; adjust request and...
test dword ptr [ecx],eax ; ...probe it
cmp eax,PAGESIZE ; more than one page requested?
jae short probepages ; no
lastpage:
sub ecx,eax ; move stack down by eax
mov eax,esp ; save current tos and do a...
test dword ptr [ecx],eax ; ...probe in case a page was crossed
mov esp,ecx ; set the new stack pointer
mov ecx,dword ptr [eax] ; recover ecx
mov eax,dword ptr [eax + 4] ; recover return address
push eax ; prepare return address
; ...probe in case a page was crossed
ret
__chkstk endp
end
| Detected encoding: ASCII (7 bit) | 2
|