strsetm.asm

来自「汇编编程艺术」· 汇编 代码 · 共 67 行

StdGrp		group	stdlib,stddata
stddata		segment	para public 'sldata'
stddata		ends
;
stdlib		segment	para public 'slcode'
		assume	cs:stdgrp
;
		extrn	sl_malloc:far
;
;
; strsetm- 	Allocates a string containing CX+1 characters and initializes
;		all but the last byte to the character passed in AL.  Zero
;		terminates the entire string.
;
; inputs:
;
;	AL-	Character to copy.
;	CX-	# of characters in new string.
;
; outputs:
;
;	es:di-	Points at newly created string (if allocated).
;
;	carry=0 if no error creating string.
;	carry=1 if insufficient memory to allocate storage for string.
;
;
;
;
		public	sl_strsetm
;
sl_strsetm	proc	far
		pushf
		push	ax
		push	cx
;
		cld
                inc	cx			;Include zero byte at EOS.
		call	sl_malloc		;Allocate space for string
		jc	ss2sc			;Branch if insufficent memory.
;
		pop	cx			;Retrieve count.
		push	cx
		push	di			;Save ptr to free memory
	rep	stosb				;Fill string with char in AL.
		mov	byte ptr es:[di], 0	;Zero terminate
		pop	di
;
ss2cc:		pop	cx
		pop	ax
		popf
                clc
		ret

ss2sc:		pop	cx
		pop	ax
		popf
		stc
		ret
sl_strsetm	endp
;
;
;
;
stdlib		ends
		end