asmlib/strcpy32.asm at master · lukego/asmlib · GitHub

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;*************************  strcpy32.asm  ************************************
; Author:           Agner Fog
; Date created:     2008-07-19
; Last modified:    2011-07-01
; Description:
; Faster version of the standard strcpy function:
; char * A_strcpy(char * dest, const char * src);
; Copies zero-terminated string from src to dest, including terminating zero.
;
; Overriding standard function memcpy:
; The alias ?OVR_strcpy is changed to _strcpy in the object file if
; it is desired to override the standard library function strcpy.
;
; Optimization:
; Uses optimized functions A_strlen and A_memcpy.
;
; Copyright (c) 2011 GNU General Public License www.gnu.org/licenses
;******************************************************************************

global _A_strcpy: function                 ; Function _A_strcpy
global ?OVR_strcpy: function               ; ?OVR removed if standard function memcpy overridden

; Imported from strlen32.asm
extern _A_strlen

; Imported from memcpy32.asm
extern _A_memcpy


SECTION .text  align=16

; extern "C" char * A_strcpy(char * dest, const char * src) {
;    return memcpy(dest, src, strlen(src)+1);
; }

; Function entry:
_A_strcpy:
?OVR_strcpy:

        mov     eax, [esp+8]           ; src
        push    eax
        call    _A_strlen              ; length of src
        pop     ecx                    ; ecx = src. Assume unchanged by _A_strlen
        inc     eax                    ; include terminating zero in length
        mov     edx, [esp+4]           ; dest
        push    eax                    ; length+1
        push    ecx                    ; src
        push    edx                    ; dest
        call    _A_memcpy              ; copy
        add     esp, 12                ; clean up stack
        ret

;_A_strcpy ENDP