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#pragma inline /* tell turbo assemble to use inline assembly */
#ifndef LINT
static char sccsid[]="$Source: /usr/home/dhesi/zoo/RCS/addbftcc.c,v $\n\
$Id: addbftcc.c,v 1.1 91/07/07 18:40:11 dhesi Exp $";
#endif /* LINT */
extern unsigned int crccode;
extern unsigned crctab[];
void addbfcrc(buffer,count)
char *buffer;
int count;
{
(void) kbhit(); /* allow keyboard interrupt to occur */
_AX = crccode; /* ax holds crccode value */
_CX = count; /* cx holds byte count */
asm les di,buffer /* es:di holds buffer address */
asm jcxz done /* if zero bytes, just skip */
/* loop begins here */
xloop:
asm sub bh,bh
asm mov bl,al
asm xor bl,es:[di] /* now bx = (crccode xor c) & 0x00ff */
/* next statement shifts _BX left (2-byte items) */
_DX = crctab[_BX]; /* dx <= *buffer == exp2 */
asm sub bh,bh /* bh = 0 */
asm mov bl,ah /* bx <- exp1 */
asm xor bx,dx /* bx <- exp1 xor exp2 */
asm mov ax,bx /* crccode <- exp1 xor exp2 */
asm inc di /* inc buffer pointer */
asm loop xloop /* dec CX, jump if not zero */
/* loop ends here */
crccode = _AX; /* put back calculated CRC value */
done:
;
}
#if 0
; The following (edited) code was generated by Turbo C from the
; preceding code. It is supplied here for porting to other systems
; and for user education.
_TEXT segment byte public 'CODE'
_TEXT ends
DGROUP group _DATA,_BSS
assume cs:_TEXT,ds:DGROUP
_DATA segment word public 'DATA'
_DATA ends
_BSS segment word public 'BSS'
_BSS ends
_TEXT segment byte public 'CODE'
assume cs:_TEXT
_addbfcrc proc near
push bp
mov bp,sp
push di
call near ptr _kbhit
mov ax,word ptr DGROUP:_crccode
mov cx,word ptr [bp+8]
les di,[bp+4]
jcxz short @1@362
@1@98:
sub bh,bh
mov bl,al
xor bl,es:[di]
shl bx,1
mov dx,word ptr DGROUP:_crctab[bx]
sub bh,bh
mov bl,ah
xor bx,dx
mov ax,bx
inc di
loop short @1@98
mov word ptr DGROUP:_crccode,ax
@1@362:
pop di
pop bp
ret
_addbfcrc endp
_TEXT ends
extrn _crccode:word
extrn _kbhit:near
extrn _crctab:word
public _addbfcrc
end
#endif
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