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|
;;
;; NASM assembler crc32
;;
;; Copyright (c) 1998-2003 by Joergen Ibsen / Jibz
;; All Rights Reserved
;;
;; http://www.ibsensoftware.com/
;;
;; This software is provided 'as-is', without any express
;; or implied warranty. In no event will the authors be
;; held liable for any damages arising from the use of
;; this software.
;;
;; Permission is granted to anyone to use this software
;; for any purpose, including commercial applications,
;; and to alter it and redistribute it freely, subject to
;; the following restrictions:
;;
;; 1. The origin of this software must not be
;; misrepresented; you must not claim that you
;; wrote the original software. If you use this
;; software in a product, an acknowledgment in
;; the product documentation would be appreciated
;; but is not required.
;;
;; 2. Altered source versions must be plainly marked
;; as such, and must not be misrepresented as
;; being the original software.
;;
;; 3. This notice may not be removed or altered from
;; any source distribution.
;;
; CRC32 algorithm taken from the zlib source, which is
; Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
cpu 386
bits 32
%include "nasmlcm.inc"
section lcmtext
lcmglobal tinf_crc32,8
lcmexport tinf_crc32,8
; =============================================================
lcmlabel tinf_crc32,8
; tinf_crc32(const void *data,
; unsigned int length);
.len$ equ 2*4 + 4 + 4
.dat$ equ 2*4 + 4
push esi
push edi
mov esi, [esp + .dat$] ; esi -> buffer
mov ecx, [esp + .len$] ; ecx = length
sub eax, eax ; crc = 0
test esi, esi
jz short .c_exit
test ecx, ecx
jz short .c_exit
dec eax ; crc = 0xffffffff
%ifdef _OBJ_
mov edi, tinf_crc32tab wrt FLAT ; edi -> crctab
%else
mov edi, tinf_crc32tab ; edi -> crctab
%endif
.c_next_byte:
xor al, [esi]
inc esi
mov edx, 0x0f
and edx, eax
shr eax, 4
xor eax, [edi + edx*4]
mov edx, 0x0f
and edx, eax
shr eax, 4
xor eax, [edi + edx*4]
dec ecx
jnz short .c_next_byte
not eax
.c_exit:
pop edi
pop esi
lcmret 8
; =============================================================
section lcmdata
tinf_crc32tab dd 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190
dd 0x6b6b51f4, 0x4db26158, 0x5005713c, 0xedb88320, 0xf00f9344
dd 0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278
dd 0xbdbdf21c
; =============================================================
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