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strcat32.asm
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strcat32.asm
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;************************* strcat32.asm ************************************
; Author: Agner Fog
; Date created: 2008-07-19
; Last modified: 2008-10-16
; Description:
; Faster version of the standard strcat function:
; char * strcat(char * dest, const char * src);
; Copies zero-terminated string from src to end of dest.
;
; Overriding standard function strcat:
; The alias ?OVR_strcat is changed to _strcat in the object file if
; it is desired to override the standard library function strcat.
;
; Optimization:
; Uses optimized functions A_strlen and A_memcpy.
;
; Copyright (c) 2009 GNU General Public License www.gnu.org/licenses
;******************************************************************************
global _A_strcat: function ; Function _A_strcat
global ?OVR_strcat: function ; ?OVR removed if standard function strcat overridden
; Imported from strlen32.asm
extern _A_strlen
; Imported from memcpy32.asm
extern _A_memcpy
SECTION .text align=16
; extern "C" char * A_strcat(char * dest, const char * src) {
; memcpy(dest+strlen(dest), src, strlen(src)+1);
; return dest
; }
; Function entry:
_A_strcat:
?OVR_strcat:
mov eax, [esp+8] ; src
push eax
call _A_strlen ; length of src
inc eax ; include terminating zero in length
push eax ; strlen(src)+1
mov edx, [esp+4+8] ; dest
push edx
call _A_strlen ; length of dest
pop edx ; dest. Assume unchanged by _A_strlen
add edx, eax ; dest+strlen(dest)
mov ecx, [esp+8+8] ; src
; strlen(src)+1 is on stack
push ecx ; src
push edx ; dest+strlen(dest)
call _A_memcpy ; copy
add esp, 16 ; clean up stack
mov eax, [esp+4] ; return dest
ret
;_A_strcat ENDP