crc64_x86.S

Last change on this file was 98730, checked in by vboxsync, 21 months ago
libs/liblzma-5.4.1: Export to OSE, bugref:10254
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1	/*
2	* Speed-optimized CRC64 using slicing-by-four algorithm
3	*
4	* This uses only i386 instructions, but it is optimized for i686 and later
5	* (including e.g. Pentium II/III/IV, Athlon XP, and Core 2).
6	*
7	* Authors: Igor Pavlov (original CRC32 assembly code)
8	* Lasse Collin (CRC64 adaptation of the modified CRC32 code)
9	*
10	* This file has been put into the public domain.
11	* You can do whatever you want with this file.
12	*
13	* This code needs lzma_crc64_table, which can be created using the
14	* following C code:
15
16	uint64_t lzma_crc64_table[4][256];
17
18	void
19	init_table(void)
20	{
21	// ECMA-182
22	static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
23
24	for (size_t s = 0; s < 4; ++s) {
25	for (size_t b = 0; b < 256; ++b) {
26	uint64_t r = s == 0 ? b : lzma_crc64_table[s - 1][b];
27
28	for (size_t i = 0; i < 8; ++i) {
29	if (r & 1)
30	r = (r >> 1) ^ poly64;
31	else
32	r >>= 1;
33	}
34
35	lzma_crc64_table[s][b] = r;
36	}
37	}
38	}
39
40	* The prototype of the CRC64 function:
41	* extern uint64_t lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc);
42	*/
43
44	/* When Intel CET is enabled, include <cet.h> in assembly code to mark
45	Intel CET support. */
46	#ifdef __CET__
47	# include <cet.h>
48	#else
49	# define _CET_ENDBR
50	#endif
51
52	/*
53	* On some systems, the functions need to be prefixed. The prefix is
54	* usually an underscore.
55	*/
56	#ifndef __USER_LABEL_PREFIX__
57	# define __USER_LABEL_PREFIX__
58	#endif
59	#define MAKE_SYM_CAT(prefix, sym) prefix ## sym
60	#define MAKE_SYM(prefix, sym) MAKE_SYM_CAT(prefix, sym)
61	#define LZMA_CRC64 MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64)
62	#define LZMA_CRC64_TABLE MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64_table)
63
64	/*
65	* Solaris assembler doesn't have .p2align, and Darwin uses .align
66	* differently than GNU/Linux and Solaris.
67	*/
68	#if defined(__APPLE__) \|\| defined(__MSDOS__)
69	# define ALIGN(pow2, abs) .align pow2
70	#else
71	# define ALIGN(pow2, abs) .align abs
72	#endif
73
74	.text
75	.globl LZMA_CRC64
76
77	#if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) \
78	&& !defined(__MSDOS__)
79	.type LZMA_CRC64, @function
80	#endif
81
82	ALIGN(4, 16)
83	LZMA_CRC64:
84	_CET_ENDBR
85	/*
86	* Register usage:
87	* %eax crc LSB
88	* %edx crc MSB
89	* %esi buf
90	* %edi size or buf + size
91	* %ebx lzma_crc64_table
92	* %ebp Table index
93	* %ecx Temporary
94	*/
95	pushl %ebx
96	pushl %esi
97	pushl %edi
98	pushl %ebp
99	movl 0x14(%esp), %esi /* buf */
100	movl 0x18(%esp), %edi /* size */
101	movl 0x1C(%esp), %eax /* crc LSB */
102	movl 0x20(%esp), %edx /* crc MSB */
103
104	/*
105	* Store the address of lzma_crc64_table to %ebx. This is needed to
106	* get position-independent code (PIC).
107	*
108	* The PIC macro is defined by libtool, while __PIC__ is defined
109	* by GCC but only on some systems. Testing for both makes it simpler
110	* to test this code without libtool, and keeps the code working also
111	* when built with libtool but using something else than GCC.
112	*
113	* I understood that libtool may define PIC on Windows even though
114	* the code in Windows DLLs is not PIC in sense that it is in ELF
115	* binaries, so we need a separate check to always use the non-PIC
116	* code on Windows.
117	*/
118	#if (!defined(PIC) && !defined(__PIC__)) \
119	\|\| (defined(_WIN32) \|\| defined(__CYGWIN__))
120	/* Not PIC */
121	movl $ LZMA_CRC64_TABLE, %ebx
122	#elif defined(__APPLE__)
123	/* Mach-O */
124	call .L_get_pc
125	.L_pic:
126	leal .L_lzma_crc64_table$non_lazy_ptr-.L_pic(%ebx), %ebx
127	movl (%ebx), %ebx
128	#else
129	/* ELF */
130	call .L_get_pc
131	addl $_GLOBAL_OFFSET_TABLE_, %ebx
132	movl LZMA_CRC64_TABLE@GOT(%ebx), %ebx
133	#endif
134
135	/* Complement the initial value. */
136	notl %eax
137	notl %edx
138
139	.L_align:
140	/*
141	* Check if there is enough input to use slicing-by-four.
142	* We need eight bytes, because the loop pre-reads four bytes.
143	*/
144	cmpl $8, %edi
145	jb .L_rest
146
147	/* Check if we have reached alignment of four bytes. */
148	testl $3, %esi
149	jz .L_slice
150
151	/* Calculate CRC of the next input byte. */
152	movzbl (%esi), %ebp
153	incl %esi
154	movzbl %al, %ecx
155	xorl %ecx, %ebp
156	shrdl $8, %edx, %eax
157	xorl (%ebx, %ebp, 8), %eax
158	shrl $8, %edx
159	xorl 4(%ebx, %ebp, 8), %edx
160	decl %edi
161	jmp .L_align
162
163	.L_slice:
164	/*
165	* If we get here, there's at least eight bytes of aligned input
166	* available. Make %edi multiple of four bytes. Store the possible
167	* remainder over the "size" variable in the argument stack.
168	*/
169	movl %edi, 0x18(%esp)
170	andl $-4, %edi
171	subl %edi, 0x18(%esp)
172
173	/*
174	* Let %edi be buf + size - 4 while running the main loop. This way
175	* we can compare for equality to determine when exit the loop.
176	*/
177	addl %esi, %edi
178	subl $4, %edi
179
180	/* Read in the first four aligned bytes. */
181	movl (%esi), %ecx
182
183	.L_loop:
184	xorl %eax, %ecx
185	movzbl %cl, %ebp
186	movl 0x1800(%ebx, %ebp, 8), %eax
187	xorl %edx, %eax
188	movl 0x1804(%ebx, %ebp, 8), %edx
189	movzbl %ch, %ebp
190	xorl 0x1000(%ebx, %ebp, 8), %eax
191	xorl 0x1004(%ebx, %ebp, 8), %edx
192	shrl $16, %ecx
193	movzbl %cl, %ebp
194	xorl 0x0800(%ebx, %ebp, 8), %eax
195	xorl 0x0804(%ebx, %ebp, 8), %edx
196	movzbl %ch, %ebp
197	addl $4, %esi
198	xorl (%ebx, %ebp, 8), %eax
199	xorl 4(%ebx, %ebp, 8), %edx
200
201	/* Check for end of aligned input. */
202	cmpl %edi, %esi
203
204	/*
205	* Copy the next input byte to %ecx. It is slightly faster to
206	* read it here than at the top of the loop.
207	*/
208	movl (%esi), %ecx
209	jb .L_loop
210
211	/*
212	* Process the remaining four bytes, which we have already
213	* copied to %ecx.
214	*/
215	xorl %eax, %ecx
216	movzbl %cl, %ebp
217	movl 0x1800(%ebx, %ebp, 8), %eax
218	xorl %edx, %eax
219	movl 0x1804(%ebx, %ebp, 8), %edx
220	movzbl %ch, %ebp
221	xorl 0x1000(%ebx, %ebp, 8), %eax
222	xorl 0x1004(%ebx, %ebp, 8), %edx
223	shrl $16, %ecx
224	movzbl %cl, %ebp
225	xorl 0x0800(%ebx, %ebp, 8), %eax
226	xorl 0x0804(%ebx, %ebp, 8), %edx
227	movzbl %ch, %ebp
228	addl $4, %esi
229	xorl (%ebx, %ebp, 8), %eax
230	xorl 4(%ebx, %ebp, 8), %edx
231
232	/* Copy the number of remaining bytes to %edi. */
233	movl 0x18(%esp), %edi
234
235	.L_rest:
236	/* Check for end of input. */
237	testl %edi, %edi
238	jz .L_return
239
240	/* Calculate CRC of the next input byte. */
241	movzbl (%esi), %ebp
242	incl %esi
243	movzbl %al, %ecx
244	xorl %ecx, %ebp
245	shrdl $8, %edx, %eax
246	xorl (%ebx, %ebp, 8), %eax
247	shrl $8, %edx
248	xorl 4(%ebx, %ebp, 8), %edx
249	decl %edi
250	jmp .L_rest
251
252	.L_return:
253	/* Complement the final value. */
254	notl %eax
255	notl %edx
256
257	popl %ebp
258	popl %edi
259	popl %esi
260	popl %ebx
261	ret
262
263	#if defined(PIC) \|\| defined(__PIC__)
264	ALIGN(4, 16)
265	.L_get_pc:
266	movl (%esp), %ebx
267	ret
268	#endif
269
270	#if defined(__APPLE__) && (defined(PIC) \|\| defined(__PIC__))
271	/* Mach-O PIC */
272	.section __IMPORT,__pointers,non_lazy_symbol_pointers
273	.L_lzma_crc64_table$non_lazy_ptr:
274	.indirect_symbol LZMA_CRC64_TABLE
275	.long 0
276
277	#elif defined(_WIN32) \|\| defined(__CYGWIN__)
278	# ifdef DLL_EXPORT
279	/* This is equivalent of __declspec(dllexport). */
280	.section .drectve
281	.ascii " -export:lzma_crc64"
282	# endif
283
284	#elif !defined(__MSDOS__)
285	/* ELF */
286	.size LZMA_CRC64, .-LZMA_CRC64
287	#endif
288
289	/*
290	* This is needed to support non-executable stack. It's ugly to
291	* use __FreeBSD__ and __linux__ here, but I don't know a way to detect when
292	* we are using GNU assembler.
293	*/
294	#if defined(__ELF__) && (defined(__FreeBSD__) \|\| defined(__linux__))
295	.section .note.GNU-stack,"",@progbits
296	#endif

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