189 lines
3.7 KiB
NASM
189 lines
3.7 KiB
NASM
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page ,132
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title chkstk - C stack checking routine
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;***
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;chkstk.asm - C stack checking routine
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;
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; Copyright (c) 1985-1990 Microsoft Corporation, All Rights Reserved
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;
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;Purpose:
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; Provides support for automatic stack checking in C procedures
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; when stack checking is enabled.
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;
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;*******************************************************************************
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.xlist
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?PLM=0
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?WIN=0
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;
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; The way this code is structured, the following switch combinations better
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; not be defined.
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;
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;
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; The USE_EXTERN flag indicates whether this module will be the default
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; stack checking module for the library or not. If so, the stack checking
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; data and subroutines must be defined. If not, the data and subroutines
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; are NOT defined (i.e., they are externals that reside in the default
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; stack checking object).
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;
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ifdef MI_NEAR
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memS equ 1 ; near version
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xchkstk equ <_aNchkstk>
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ifdef mem_m ; if the default memory model is
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USE_EXTERNS equ 1 ; medium or large, then use externs
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endif ; in this module
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ifdef mem_l
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USE_EXTERNS equ 1
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endif
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elseifdef MI_FAR
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memM equ 1 ; far version
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xchkstk equ <_aFchkstk>
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ifdef mem_s ; if the default memory model is
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USE_EXTERNS equ 1 ; small or compact, then use externs
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endif ; in this module
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ifdef mem_c
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USE_EXTERNS equ 1
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endif
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else
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include version.inc ; default version
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endif
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include cmacros.inc
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include msdos.inc
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.list
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sBegin data
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assumes ds,data
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extrn _end:word ; stack bottom
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ifdef USE_EXTERNS
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; Use the data that is in the default stack checking module.
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if sizeC
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externCP _aaltstkovr ; alternate stack overflow
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endif
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extrn STKHQQ:word
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else ;not USE_EXTERNS
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globalCP _aaltstkovr,-1 ; alternate stack overflow -- define always so
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; mixed model works
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public STKHQQ ; used by parasitic heap
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ifdef FARSTACK
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;far stack has bottom at 0
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STKHQQ dw STACKSLOP ; initial value
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else
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STKHQQ dw dataoffset _end+STACKSLOP ; initial value
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endif
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endif ;not USE_EXTERNS
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sEnd data
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sBegin code
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assumes ds,data
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assumes cs,code
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externNP _amsg_exit ; write error and die
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page
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;***
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;_chkstk - check stack upon procedure entry
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;
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;Purpose:
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; Provide stack checking on procedure entry.
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;
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; [LLIBCDLL.LIB NOTE: Unlike other LLIBCDLL routines, DS != DGROUP
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; when chkstk() is called.]
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;
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;Entry:
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; AX = size of local frame
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;
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;Exit:
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; SP = new stackframe if successful
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;
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;Uses:
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; AX, BX, CX, DX
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;
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;Exceptions:
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; Gives out of memory error and aborts if there is not enough
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; stack space for the routine.
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;
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;*******************************************************************************
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ifndef USE_EXTERNS
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; Define old label name in default model version
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labelP <PUBLIC,_chkstk>
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endif
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% labelP <PUBLIC,xchkstk>
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if sizeC
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pop cx ; get return offset
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pop dx ; get return segment
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else
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pop cx ; get return offset
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endif
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mov bx,sp ; bp = current SP
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sub bx,ax ; bx = new position
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jc OMerr ; error - out of memory
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cmp bx,[STKHQQ] ; SP - AX : STKHQQ (for heap/stack)
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jb OMerr ; error - out of memory
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mov sp,bx ; set new stack pointer
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if sizeC
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push dx ; push segment
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push cx ; push offset
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chkproc proc far
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ret ; far return to dx:cx
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chkproc endp
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else
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jmp cx ; return to cx
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endif
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OMerr:
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if sizeC
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push dx ; user segment
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endif
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push cx ; user offset
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if sizeC
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mov ax,word ptr [_aaltstkovr]
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inc ax
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jnz altstkovr
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endif
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xor ax,ax
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jmp _amsg_exit ; give stack overflow and die
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if sizeC
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altstkovr:
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jmp [_aaltstkovr] ; Pascal/FORTRAN stack overflow
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endif
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sEnd code
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end
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