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Diffstat (limited to 'win32/crc_i386.c')
| -rw-r--r-- | win32/crc_i386.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/win32/crc_i386.c b/win32/crc_i386.c new file mode 100644 index 0000000..e8a2faf --- /dev/null +++ b/win32/crc_i386.c @@ -0,0 +1,228 @@ +/* + Copyright (c) 1990-2005 Info-ZIP. All rights reserved. + + See the accompanying file LICENSE, version 2004-May-22 or later + (the contents of which are also included in zip.h) for terms of use. + If, for some reason, both of these files are missing, the Info-ZIP license + also may be found at: ftp://ftp.info-zip.org/pub/infozip/license.html +*/ +/* crc_i386.c -- Microsoft 32-bit C/C++ adaptation of crc_i386.asm + * Created by Rodney Brown from crc_i386.asm, modified by Chr. Spieler. + * + * Original coded (in crc_i386.asm) and put into the public domain + * by Paul Kienitz and Christian Spieler. + * + * Revised 06-Oct-96, Scott Field (sfield@microsoft.com) + * fixed to assemble with masm by not using .model directive which makes + * assumptions about segment alignment. Also, + * avoid using loop, and j[e]cxz where possible. Use mov + inc, rather + * than lodsb, and other misc. changes resulting in the following performance + * increases: + * + * unrolled loops NO_UNROLLED_LOOPS + * *8 >8 <8 *8 >8 <8 + * + * +54% +42% +35% +82% +52% +25% + * + * first item in each table is input buffer length, even multiple of 8 + * second item in each table is input buffer length, > 8 + * third item in each table is input buffer length, < 8 + * + * Revised 02-Apr-97, Chr. Spieler, based on Rodney Brown (rdb@cmutual.com.au) + * Incorporated Rodney Brown's 32-bit-reads optimization as found in the + * UNIX AS source crc_i386.S. This new code can be disabled by defining + * the macro symbol NO_32_BIT_LOADS. + * + * Revised 12-Oct-97, Chr. Spieler, based on Rodney Brown (rdb@cmutual.com.au) + * Incorporated Rodney Brown's additional tweaks for 32-bit-optimized CPUs + * (like the Pentium Pro, Pentium II, and probably some Pentium clones). + * This optimization is controlled by the macro symbol __686 and is disabled + * by default. (This default is based on the assumption that most users + * do not yet work on a Pentium Pro or Pentium II machine ...) + * + * Revised 16-Nov-97, Chr. Spieler: Made code compatible with Borland C++ + * 32-bit, removed unneeded kludge for potentially unknown movzx mnemonic, + * confirmed correct working with MS VC++ (32-bit). + * + * Revised 22-May-98, Peter Kunath, Chr. Spieler: The 16-Nov-97 revision broke + * MSVC 5.0. Inside preprocessor macros, each instruction is enclosed in its + * own __asm {...} construct. For MSVC, a "#pragma warning" was added to + * shut up the "no return value" warning message. + * + * Revised 13-Dec-98, Chr. Spieler: Modified path to "zip.h" header file. + * + * Revised 16-Jan-2005, Cosmin Truta: Added the ASM_CRC guard, for easier + * switching between ASM vs. non-ASM builds, when handling makefiles. + * Also enabled the 686 build by default, because there are hardly any + * pre-686 CPUs in serious use nowadays. (See the 12-Oct-97 note above.) + * + * FLAT memory model assumed. + * + * Loop unrolling can be disabled by defining the macro NO_UNROLLED_LOOPS. + * This results in shorter code at the expense of reduced performance. + * + */ + +#include "../zip.h" + +#if defined(ASM_CRC) && !defined(USE_ZLIB) + +#if !defined(PRE_686) && !defined(__686) +# define __686 +#endif + +#ifndef ZCONST +# define ZCONST const +#endif + +/* Select wether the following inline-assember code is supported. */ +#if (defined(_MSC_VER) && _MSC_VER >= 700) +#if (defined(_M_IX86) && _M_IX86 >= 300) +# define MSC_INLINE_ASM_32BIT_SUPPORT + /* Disable warning for no return value, typical of asm functions */ +# pragma warning( disable : 4035 ) +#endif +#endif + +#if (defined(__BORLANDC__) && __BORLANDC__ >= 452) +# define MSC_INLINE_ASM_32BIT_SUPPORT +#endif + +#ifdef MSC_INLINE_ASM_32BIT_SUPPORT +/* This code is intended for Microsoft C/C++ (32-bit) compatible compilers. */ + +/* + * These two (three) macros make up the loop body of the CRC32 cruncher. + * registers modified: + * eax : crc value "c" + * esi : pointer to next data byte (or dword) "buf++" + * registers read: + * edi : pointer to base of crc_table array + * scratch registers: + * ebx : index into crc_table array + * (requires upper three bytes = 0 when __686 is undefined) + */ +#ifndef __686 +#define Do_CRC { \ + __asm { mov bl, al }; \ + __asm { shr eax, 8 }; \ + __asm { xor eax, [edi+ebx*4] }; } +#else /* __686 */ +#define Do_CRC { \ + __asm { movzx ebx, al }; \ + __asm { shr eax, 8 }; \ + __asm { xor eax, [edi+ebx*4] }; } +#endif /* ?__686 */ + +#define Do_CRC_byte { \ + __asm { xor al, byte ptr [esi] }; \ + __asm { inc esi }; \ + Do_CRC; } + +#ifndef NO_32_BIT_LOADS +#define Do_CRC_dword { \ + __asm { xor eax, dword ptr [esi] }; \ + __asm { add esi, 4 }; \ + Do_CRC; \ + Do_CRC; \ + Do_CRC; \ + Do_CRC; } +#endif /* !NO_32_BIT_LOADS */ + +/* ========================================================================= */ +ulg crc32(crc, buf, len) + ulg crc; /* crc shift register */ + ZCONST uch *buf; /* pointer to bytes to pump through */ + extent len; /* number of bytes in buf[] */ +/* Run a set of bytes through the crc shift register. If buf is a NULL + pointer, then initialize the crc shift register contents instead. + Return the current crc in either case. */ +{ + __asm { + push edx + push ecx + + mov esi,buf ;/* 2nd arg: uch *buf */ + sub eax,eax ;/*> if (!buf) */ + test esi,esi ;/*> return 0; */ + jz fine ;/*> else { */ + + call get_crc_table + mov edi,eax + mov eax,crc ;/* 1st arg: ulg crc */ +#ifndef __686 + sub ebx,ebx ;/* ebx=0; => bl usable as a dword */ +#endif + mov ecx,len ;/* 3rd arg: extent len */ + not eax ;/*> c = ~crc; */ + + test ecx,ecx +#ifndef NO_UNROLLED_LOOPS + jz bail +# ifndef NO_32_BIT_LOADS +align_loop: + test esi,3 ;/* align buf pointer on next */ + jz aligned_now ;/* dword boundary */ + } + Do_CRC_byte ; + __asm { + dec ecx + jnz align_loop +aligned_now: +# endif /* !NO_32_BIT_LOADS */ + mov edx,ecx ;/* save len in edx */ + shr ecx,3 ;/* ecx = len / 8 */ + jz No_Eights +; align loop head at start of 486 internal cache line !! + align 16 +Next_Eight: + } +# ifndef NO_32_BIT_LOADS + Do_CRC_dword ; + Do_CRC_dword ; +# else /* NO_32_BIT_LOADS */ + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; + Do_CRC_byte ; +# endif /* ?NO_32_BIT_LOADS */ + __asm { + dec ecx + jnz Next_Eight +No_Eights: + mov ecx,edx + and ecx,000000007H ;/* ecx = len % 8 */ + +#endif /* !NO_UNROLLED_LOOPS */ + jz bail ;/*> if (len) */ +; align loop head at start of 486 internal cache line !! + align 16 +loupe: ;/*> do { */ + } + Do_CRC_byte ;/* c = CRC32(c, *buf++); */ + __asm { + dec ecx ;/*> } while (--len); */ + jnz loupe + +bail: ;/*> } */ + not eax ;/*> return ~c; */ +fine: + pop ecx + pop edx + } +#ifdef NEED_RETURN + return _EAX; +#endif +} +#endif /* MSC_INLINE_ASM_32BIT_SUPPORT */ +#if (defined(_MSC_VER) && _MSC_VER >= 700) +#if (defined(_M_IX86) && _M_IX86 >= 300) + /* Reenable missing return value warning */ +# pragma warning( default : 4035 ) +#endif +#endif +#endif /* ASM_CRC && !USE_ZLIB */ |