forked from KolibriOS/kolibrios
Rustem Gimadutdinov (rgimad)
73864ff1d7
git-svn-id: svn://kolibrios.org@9019 a494cfbc-eb01-0410-851d-a64ba20cac60
43 lines
1.2 KiB
PHP
43 lines
1.2 KiB
PHP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
;; ;;
|
|
;; Copyright (C) KolibriOS team 2004-2017. All rights reserved. ;;
|
|
;; Distributed under terms of the GNU General Public License. ;;
|
|
;; ;;
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
$Revision$
|
|
|
|
; This crc32 routine doesn't use precomputed table to allow different
|
|
; polynomials, which is the first param.
|
|
; Partial hash in assumed to be eax (both in and out).
|
|
; Usage:
|
|
; 1. mov eax, -1
|
|
; 2. stdcall crypto.crc32 zero or more times
|
|
; 3. xor eax, -1
|
|
proc crc_32 _poly, _buffer, _length
|
|
push ebx ecx edx esi
|
|
|
|
mov esi, [_buffer]
|
|
.next_byte:
|
|
dec [_length]
|
|
js .done
|
|
movzx ebx, byte[esi]
|
|
inc esi
|
|
mov ecx, 8
|
|
.next_bit:
|
|
mov edx, eax
|
|
xor edx, ebx
|
|
shr eax, 1
|
|
test edx, 1
|
|
jz @f
|
|
xor eax, [_poly]
|
|
@@:
|
|
shr ebx, 1
|
|
dec ecx
|
|
jnz .next_bit
|
|
jmp .next_byte
|
|
.done:
|
|
pop esi edx ecx ebx
|
|
ret
|
|
endp
|