WebSVN – Kolibri OS – Blame – /programs/fs/unzip60/win32/crc_i386.asm

Rev	Author	Line No.	Line
6725	siemargl	1	;===========================================================================
		2	; Copyright (c) 1990-2007 Info-ZIP. All rights reserved.
		3	;
		4	; See the accompanying file LICENSE, version 2000-Apr-09 or later
		5	; (the contents of which are also included in zip.h) for terms of use.
		6	; If, for some reason, all these files are missing, the Info-ZIP license
		7	; also may be found at: ftp://ftp.info-zip.org/pub/infozip/license.html
		8	;===========================================================================
		9	; crc_i386.asm, optimized CRC calculation function for Zip and UnZip,
		10	; created by Paul Kienitz and Christian Spieler. Last revised 07 Jan 2007.
		11	;
		12	; Revised 06-Oct-96, Scott Field (sfield@microsoft.com)
		13	; fixed to assemble with masm by not using .model directive which makes
		14	; assumptions about segment alignment. Also,
		15	; avoid using loop, and j[e]cxz where possible. Use mov + inc, rather
		16	; than lodsb, and other misc. changes resulting in the following performance
		17	; increases:
		18	;
		19	; unrolled loops NO_UNROLLED_LOOPS
		20	; 8 >8 <8 8 >8 <8
		21	;
		22	; +54% +42% +35% +82% +52% +25%
		23	;
		24	; first item in each table is input buffer length, even multiple of 8
		25	; second item in each table is input buffer length, > 8
		26	; third item in each table is input buffer length, < 8
		27	;
		28	; Revised 02-Apr-97, Chr. Spieler, based on Rodney Brown (rdb@cmutual.com.au)
		29	; Incorporated Rodney Brown's 32-bit-reads optimization as found in the
		30	; UNIX AS source crc_i386.S. This new code can be disabled by defining
		31	; the macro symbol NO_32_BIT_LOADS.
		32	;
		33	; Revised 12-Oct-97, Chr. Spieler, based on Rodney Brown (rdb@cmutual.com.au)
		34	; Incorporated Rodney Brown's additional tweaks for 32-bit-optimized CPUs
		35	; (like the Pentium Pro, Pentium II, and probably some Pentium clones).
		36	; This optimization is controlled by the macro symbol __686 and is disabled
		37	; by default. (This default is based on the assumption that most users
		38	; do not yet work on a Pentium Pro or Pentium II machine ...)
		39	;
		40	; Revised 25-Mar-98, Cosmin Truta (cosmint@cs.ubbcluj.ro)
		41	; Working without .model directive caused tasm32 version 5.0 to produce
		42	; bad object code. The optimized alignments can be optionally disabled
		43	; by defining NO_ALIGN, thus allowing to use .model flat. There is no need
		44	; to define this macro if using other versions of tasm.
		45	;
		46	; Revised 16-Jan-2005, Cosmin Truta (cosmint@cs.ubbcluj.ro)
		47	; Enabled the 686 build by default, because there are hardly any pre-686 CPUs
		48	; in serious use nowadays. (See the 12-Oct-97 note above.)
		49	;
		50	; Revised 03-Jan-2006, Chr. Spieler
		51	; Enlarged unrolling loops to "do 16 bytes per turn"; optimized access to
		52	; data buffer in loop body (adjust pointer only once in loop body and use
		53	; offsets to access each item); added additional support for the "unfolded
		54	; tables" optimization variant (enabled by IZ_CRCOPTIM_UNFOLDTBL).
		55	;
		56	; Revised 07-Jan-2007, Chr. Spieler
		57	; Recognize additional conditional flag CRC_TABLE_ONLY that prevents
		58	; compilation of the crc32() function.
		59	;
		60	; FLAT memory model assumed.
		61	;
		62	; Loop unrolling can be disabled by defining the macro NO_UNROLLED_LOOPS.
		63	; This results in shorter code at the expense of reduced performance.
		64	;
		65	;==============================================================================
		66	;
		67	; Do NOT assemble this source if external crc32 routine from zlib gets used,
		68	; or only the precomputed CRC_32_Table is needed.
		69	;
		70	IFNDEF USE_ZLIB
		71	IFNDEF CRC_TABLE_ONLY
		72	;
		73	.386p
		74	name crc_i386
		75
		76	IFDEF NO_ALIGN
		77	.model flat
		78	ENDIF
		79
		80	IFNDEF PRE_686
		81	IFNDEF __686
		82	__686 EQU 1 ; optimize for Pentium Pro, Pentium II and compatible CPUs
		83	ENDIF
		84	ENDIF
		85
		86	extrn _get_crc_table:near ; ZCONST ulg near *get_crc_table(void);
		87
		88	;
		89	IFNDEF NO_STD_STACKFRAME
		90	; Use a `standard' stack frame setup on routine entry and exit.
		91	; Actually, this option is set as default, because it results
		92	; in smaller code !!
		93	STD_ENTRY MACRO
		94	push ebp
		95	mov ebp,esp
		96	ENDM
		97
		98	Arg1 EQU 08H[ebp]
		99	Arg2 EQU 0CH[ebp]
		100	Arg3 EQU 10H[ebp]
		101
		102	STD_LEAVE MACRO
		103	pop ebp
		104	ENDM
		105
		106	ELSE ; NO_STD_STACKFRAME
		107
		108	STD_ENTRY MACRO
		109	ENDM
		110
		111	Arg1 EQU 18H[esp]
		112	Arg2 EQU 1CH[esp]
		113	Arg3 EQU 20H[esp]
		114
		115	STD_LEAVE MACRO
		116	ENDM
		117
		118	ENDIF ; ?NO_STD_STACKFRAME
		119
		120	; These two (three) macros make up the loop body of the CRC32 cruncher.
		121	; registers modified:
		122	; eax : crc value "c"
		123	; esi : pointer to next data byte (or dword) "buf++"
		124	; registers read:
		125	; edi : pointer to base of crc_table array
		126	; scratch registers:
		127	; ebx : index into crc_table array
		128	; (requires upper three bytes = 0 when __686 is undefined)
		129	IFNDEF __686 ; optimize for 386, 486, Pentium
		130	Do_CRC MACRO
		131	mov bl,al ; tmp = c & 0xFF
		132	shr eax,8 ; c = (c >> 8)
		133	xor eax,[edi+ebx*4] ; ^ table[tmp]
		134	ENDM
		135	ELSE ; __686 : optimize for Pentium Pro, Pentium II and compatible CPUs
		136	Do_CRC MACRO
		137	movzx ebx,al ; tmp = c & 0xFF
		138	shr eax,8 ; c = (c >> 8)
		139	xor eax,[edi+ebx*4] ; ^ table[tmp]
		140	ENDM
		141	ENDIF ; ?__686
		142	Do_CRC_byte MACRO
		143	xor al, byte ptr [esi] ; c ^= *buf
		144	inc esi ; buf++
		145	Do_CRC ; c = (c >> 8) ^ table[c & 0xFF]
		146	ENDM
		147	Do_CRC_byteof MACRO ofs
		148	xor al, byte ptr [esi+ofs] ; c ^= *(buf+ofs)
		149	Do_CRC ; c = (c >> 8) ^ table[c & 0xFF]
		150	ENDM
		151	IFNDEF NO_32_BIT_LOADS
		152	IFDEF IZ_CRCOPTIM_UNFOLDTBL
		153	; the edx register is needed in crc calculation
		154	SavLen EQU Arg3
		155
		156	UpdCRC_dword MACRO
		157	movzx ebx,al ; tmp = c & 0xFF
		158	mov edx,[edi+ebx4+3072] ; table[2563+tmp]
		159	movzx ebx,ah ; tmp = (c>>8) & 0xFF
		160	shr eax,16 ;
		161	xor edx,[edi+ebx4+2048] ; ^ table[2562+tmp]
		162	movzx ebx,al ; tmp = (c>>16) & 0xFF
		163	shr eax,8 ; tmp = (c>>24)
		164	xor edx,[edi+ebx4+1024] ; ^ table[2561+tmp]
		165	mov eax,[edi+eax4] ; ^ table[2560+tmp]
		166	xor eax,edx ; ..
		167	ENDM
		168	UpdCRC_dword_sh MACRO dwPtrIncr
		169	movzx ebx,al ; tmp = c & 0xFF
		170	mov edx,[edi+ebx4+3072] ; table[2563+tmp]
		171	movzx ebx,ah ; tmp = (c>>8) & 0xFF
		172	xor edx,[edi+ebx4+2048] ; ^ table[2562+tmp]
		173	shr eax,16 ;
		174	movzx ebx,al ; tmp = (c>>16) & 0xFF
		175	add esi, 4dwPtrIncr ; ((ulg )buf) += dwPtrIncr
		176	shr eax,8 ; tmp = (c>>24)
		177	xor edx,[edi+ebx4+1024] ; ^ table[2561+tmp]
		178	mov eax,[edi+eax4] ; ^ table[2560+tmp]
		179	xor eax,edx ; ..
		180	ENDM
		181	ELSE ; IZ_CRCOPTIM_UNFOLDTBL
		182	; the edx register is not needed anywhere else
		183	SavLen EQU edx
		184
		185	UpdCRC_dword MACRO
		186	Do_CRC
		187	Do_CRC
		188	Do_CRC
		189	Do_CRC
		190	ENDM
		191	UpdCRC_dword_sh MACRO dwPtrIncr
		192	Do_CRC
		193	Do_CRC
		194	add esi, 4dwPtrIncr ; ((ulg )buf) += dwPtrIncr
		195	Do_CRC
		196	Do_CRC
		197	ENDM
		198	ENDIF ; ?IZ_CRCOPTIM_UNFOLDTBL
		199	Do_CRC_dword MACRO
		200	xor eax, dword ptr [esi] ; c ^= (ulg )buf
		201	UpdCRC_dword_sh 1 ; ... ((ulg *)buf)++
		202	ENDM
		203	Do_CRC_4dword MACRO
		204	xor eax, dword ptr [esi] ; c ^= (ulg )buf
		205	UpdCRC_dword
		206	xor eax, dword ptr [esi+4] ; c ^= ((ulg )buf+1)
		207	UpdCRC_dword
		208	xor eax, dword ptr [esi+8] ; c ^= ((ulg )buf+2)
		209	UpdCRC_dword
		210	xor eax, dword ptr [esi+12] ; c ^= ((ulg )buf]+3
		211	UpdCRC_dword_sh 4 ; ... ((ulg *)buf)+=4
		212	ENDM
		213	ENDIF ; !NO_32_BIT_LOADS
		214
		215	IFNDEF NO_ALIGN
		216	_TEXT segment use32 para public 'CODE'
		217	ELSE
		218	_TEXT segment use32
		219	ENDIF
		220	assume CS: _TEXT
		221
		222	public _crc32
		223	_crc32 proc near ; ulg crc32(ulg crc, ZCONST uch *buf, extent len)
		224	STD_ENTRY
		225	push edi
		226	push esi
		227	push ebx
		228	push edx
		229	push ecx
		230
		231	mov esi,Arg2 ; 2nd arg: uch *buf
		232	sub eax,eax ;> if (!buf)
		233	test esi,esi ;> return 0;
		234	jz fine ;> else {
		235
		236	call _get_crc_table
		237	mov edi,eax
		238	mov eax,Arg1 ; 1st arg: ulg crc
		239	IFNDEF __686
		240	sub ebx,ebx ; ebx=0; make bl usable as a dword
		241	ENDIF
		242	mov ecx,Arg3 ; 3rd arg: extent len
		243	not eax ;> c = ~crc;
		244
		245	test ecx,ecx
		246	IFNDEF NO_UNROLLED_LOOPS
		247	jz bail
		248	IFNDEF NO_32_BIT_LOADS
		249	align_loop:
		250	test esi,3 ; align buf pointer on next
		251	jz SHORT aligned_now ; dword boundary
		252	Do_CRC_byte
		253	dec ecx
		254	jnz align_loop
		255	aligned_now:
		256	ENDIF ; !NO_32_BIT_LOADS
		257	mov SavLen,ecx ; save current len for later
		258	shr ecx,4 ; ecx = len / 16
		259	jz No_Sixteens
		260	IFNDEF NO_ALIGN
		261	; align loop head at start of 486 internal cache line !!
		262	align 16
		263	ENDIF
		264	Next_Sixteen:
		265	IFNDEF NO_32_BIT_LOADS
		266	Do_CRC_4dword
		267	ELSE ; NO_32_BIT_LOADS
		268	Do_CRC_byteof 0
		269	Do_CRC_byteof 1
		270	Do_CRC_byteof 2
		271	Do_CRC_byteof 3
		272	Do_CRC_byteof 4
		273	Do_CRC_byteof 5
		274	Do_CRC_byteof 6
		275	Do_CRC_byteof 7
		276	Do_CRC_byteof 8
		277	Do_CRC_byteof 9
		278	Do_CRC_byteof 10
		279	Do_CRC_byteof 11
		280	Do_CRC_byteof 12
		281	Do_CRC_byteof 13
		282	Do_CRC_byteof 14
		283	Do_CRC_byteof 15
		284	add esi, 16 ; buf += 16
		285	ENDIF ; ?NO_32_BIT_LOADS
		286	dec ecx
		287	jnz Next_Sixteen
		288	No_Sixteens:
		289	mov ecx,SavLen
		290	and ecx,00000000FH ; ecx = len % 16
		291	IFNDEF NO_32_BIT_LOADS
		292	shr ecx,2 ; ecx = len / 4
		293	jz SHORT No_Fours
		294	Next_Four:
		295	Do_CRC_dword
		296	dec ecx
		297	jnz Next_Four
		298	No_Fours:
		299	mov ecx,SavLen
		300	and ecx,000000003H ; ecx = len % 4
		301	ENDIF ; !NO_32_BIT_LOADS
		302	ENDIF ; !NO_UNROLLED_LOOPS
		303	jz SHORT bail ;> if (len)
		304	IFNDEF NO_ALIGN
		305	; align loop head at start of 486 internal cache line !!
		306	align 16
		307	ENDIF
		308	loupe: ;> do {
		309	Do_CRC_byte ; c = CRC32(c,*buf++,crctab);
		310	dec ecx ;> } while (--len);
		311	jnz loupe
		312
		313	bail: ;> }
		314	not eax ;> return ~c;
		315	fine:
		316	pop ecx
		317	pop edx
		318	pop ebx
		319	pop esi
		320	pop edi
		321	STD_LEAVE
		322	ret
		323	_crc32 endp
		324
		325	_TEXT ends
		326	;
		327	ENDIF ; !CRC_TABLE_ONLY
		328	ENDIF ; !USE_ZLIB
		329	;
		330	end

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(root)/programs/fs/unzip60/win32/crc_i386.asm – Rev 6725