Category : Assembly Language Source Code
Archive   : RHSTDLIB.ZIP
Filename : STRCAT2.ASM

stdlib segment para public 'slcode'
assume cs:stdlib
;
extrn sl_malloc:far
;
; strcat2-Computes the lengths of two strings pointed at by es:di and dx:si
; then allocates storage for a string long enough to hold the con-
; catentation of these two strings. Finally, it concatenates the
; two strings storing the resulting string into the new buffer.
; Returns ED:SI pointing at the new string.
;
; inputs:
;
; ES:DI- Points at the first string.
;
; DX:SI- Points at the string to append.
;
;
; outputs:
;
; ES:DI- Points at new string containing the concatenation of the
; two strings.
;
; carry=0 if no error.
; carry=1 if strcat2 could not allocate enough memory to hold
; the resulting string.
;
public sl_strcat2
;
scptr1 dd ?
strlen1 dw ?
scptr2 dd ?
strlen2 dw ?
;
sl_strcat2 proc far
push ds
push si
push cx
push ax
pushf
cld
;
; Save pointers to the strings
;
mov word ptr cs:scptr1, di
mov word ptr cs:scptr1+2, es
mov word ptr cs:scptr2, si
mov word ptr cs:scptr2+2, dx
;
; Compute the length of the second string.
;
mov al, 0
les di, cs:scptr2
mov cx, 0ffffh
repne scasb
neg cx
dec cx
mov cs:StrLen2, cx
;
; Find the end of the first string:
;
les di, cs:scptr1
mov cx, 0ffffh
repne scasb
neg cx
dec cx
dec cx
mov cs:StrLen1, cx
;
; Malloc the appropriate storage:
;
add cx, cs:StrLen2
call sl_malloc
jc BadStrCat2
;
; Save ptr to dest
;
push es
push di
;
; Copy the strings:
;
lds si, cs:scptr1
mov cx, cs:strlen1
shr cx, 1
jnc cs1
lodsb
stosb
cs1: rep movsw
lds si, cs:scptr2
mov cx, cs:strlen2
shr cx, 1
jnc cs2
lodsb
stosb
cs2: rep movsw
;
pop di
pop es
popf
pop ax
pop cx
pop si
pop ds
clc
ret
;
BadStrCat2: les di, cs:scptr1
popf
pop ax
pop cx
pop si
pop ds
stc
ret
sl_strcat2 endp
;
;
stdlib ends
end