reactos/sdk/lib/ucrt/string/i386/strset.asm

78 lines
1.9 KiB
NASM

page ,132
title strset - set all characters of string to character
;***
;strset.asm - sets all charcaters of string to given character
;
; Copyright (c) Microsoft Corporation. All rights reserved.
;
;Purpose:
; defines _strset() - sets all of the characters in a string (except
; the '\0') equal to a given character.
;
;*******************************************************************************
.xlist
include cruntime.inc
.list
page
;***
;char *_strset(string, val) - sets all of string to val
;
;Purpose:
; Sets all of characters in string (except the terminating '/0'
; character) equal to val.
;
; Algorithm:
; char *
; _strset (string, val)
; char *string;
; char val;
; {
; char *start = string;
;
; while (*string)
; *string++ = val;
; return(start);
; }
;
;Entry:
; char *string - string to modify
; char val - value to fill string with
;
;Exit:
; returns string -- now filled with val's
;
;Uses:
;
;Exceptions:
;
;*******************************************************************************
CODESEG
public _strset
_strset proc \
uses edi, \
string:ptr byte, \
val:byte
mov edi,[string] ; di = string
mov edx,edi ; dx=string addr; save return value
xor eax,eax ; ax = 0
or ecx,-1 ; cx = -1
repne scasb ; scan string & count bytes
add ecx,2 ; cx=-strlen
neg ecx ; cx=strlen
mov al,[val] ; al = byte value to store
mov edi,edx ; di=string addr
rep stosb
mov eax,edx ; return value: string addr
ret ; _cdecl return
_strset endp
end