src/liblzma/check/crc64_x86.S - xz - Git at Google

 /*
  * Speed-optimized CRC64 using slicing-by-four algorithm
  *
  * This uses only i386 instructions, but it is optimized for i686 and later
  * (including e.g. Pentium II/III/IV, Athlon XP, and Core 2).
  *
  * Authors: Igor Pavlov (original CRC32 assembly code)
  *          Lasse Collin (CRC64 adaptation of the modified CRC32 code)
  *
  * This file has been put into the public domain.
  * You can do whatever you want with this file.
  *
  * This code needs lzma_crc64_table, which can be created using the
  * following C code:

 uint64_t lzma_crc64_table[4][256];

 void
 init_table(void)
 {
 	// ECMA-182
 	static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);

 	for (size_t s = 0; s < 4; ++s) {
 		for (size_t b = 0; b < 256; ++b) {
 			uint64_t r = s == 0 ? b : lzma_crc64_table[s - 1][b];

 			for (size_t i = 0; i < 8; ++i) {
 				if (r & 1)
 					r = (r >> 1) ^ poly64;
 				else
 					r >>= 1;
 			}

 			lzma_crc64_table[s][b] = r;
 		}
 	}
 }

  * The prototype of the CRC64 function:
  * extern uint64_t lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc);
  */

 /*
  * On some systems, the functions need to be prefixed. The prefix is
  * usually an underscore.
  */
 #ifndef __USER_LABEL_PREFIX__
 #	define __USER_LABEL_PREFIX__
 #endif
 #define MAKE_SYM_CAT(prefix, sym) prefix ## sym
 #define MAKE_SYM(prefix, sym) MAKE_SYM_CAT(prefix, sym)
 #define LZMA_CRC64 MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64)
 #define LZMA_CRC64_TABLE MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64_table)

 /*
  * Solaris assembler doesn't have .p2align, and Darwin uses .align
  * differently than GNU/Linux and Solaris.
  */
 #if defined(__APPLE__) || defined(__MSDOS__)
 #	define ALIGN(pow2, abs) .align pow2
 #else
 #	define ALIGN(pow2, abs) .align abs
 #endif

 	.text
 	.globl	LZMA_CRC64

 #if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) \
 		&& !defined(__MSDOS__)
 	.type	LZMA_CRC64, @function
 #endif

 	ALIGN(4, 16)
 LZMA_CRC64:
 	/*
 	 * Register usage:
 	 * %eax crc LSB
 	 * %edx crc MSB
 	 * %esi buf
 	 * %edi size or buf + size
 	 * %ebx lzma_crc64_table
 	 * %ebp Table index
 	 * %ecx Temporary
 	 */
 	pushl	%ebx
 	pushl	%esi
 	pushl	%edi
 	pushl	%ebp
 	movl	0x14(%esp), %esi /* buf */
 	movl	0x18(%esp), %edi /* size */
 	movl	0x1C(%esp), %eax /* crc LSB */
 	movl	0x20(%esp), %edx /* crc MSB */

 	/*
 	 * Store the address of lzma_crc64_table to %ebx. This is needed to
 	 * get position-independent code (PIC).
 	 *
 	 * The PIC macro is defined by libtool, while __PIC__ is defined
 	 * by GCC but only on some systems. Testing for both makes it simpler
 	 * to test this code without libtool, and keeps the code working also
 	 * when built with libtool but using something else than GCC.
 	 *
 	 * I understood that libtool may define PIC on Windows even though
 	 * the code in Windows DLLs is not PIC in sense that it is in ELF
 	 * binaries, so we need a separate check to always use the non-PIC
 	 * code on Windows.
 	 */
 #if (!defined(PIC) && !defined(__PIC__)) \
 		|| (defined(_WIN32) || defined(__CYGWIN__))
 	/* Not PIC */
 	movl	$ LZMA_CRC64_TABLE, %ebx
 #elif defined(__APPLE__)
 	/* Mach-O */
 	call	.L_get_pc
 .L_pic:
 	leal	.L_lzma_crc64_table$non_lazy_ptr-.L_pic(%ebx), %ebx
 	movl	(%ebx), %ebx
 #else
 	/* ELF */
 	call	.L_get_pc
 	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
 	movl	LZMA_CRC64_TABLE@GOT(%ebx), %ebx
 #endif

 	/* Complement the initial value. */
 	notl	%eax
 	notl	%edx

 .L_align:
 	/*
 	 * Check if there is enough input to use slicing-by-four.
 	 * We need eight bytes, because the loop pre-reads four bytes.
 	 */
 	cmpl	$8, %edi
 	jb	.L_rest

 	/* Check if we have reached alignment of four bytes. */
 	testl	$3, %esi
 	jz	.L_slice

 	/* Calculate CRC of the next input byte. */
 	movzbl	(%esi), %ebp
 	incl	%esi
 	movzbl	%al, %ecx
 	xorl	%ecx, %ebp
 	shrdl	$8, %edx, %eax
 	xorl	(%ebx, %ebp, 8), %eax
 	shrl	$8, %edx
 	xorl	4(%ebx, %ebp, 8), %edx
 	decl	%edi
 	jmp	.L_align

 .L_slice:
 	/*
 	 * If we get here, there's at least eight bytes of aligned input
 	 * available. Make %edi multiple of four bytes. Store the possible
 	 * remainder over the "size" variable in the argument stack.
 	 */
 	movl	%edi, 0x18(%esp)
 	andl	$-4, %edi
 	subl	%edi, 0x18(%esp)

 	/*
 	 * Let %edi be buf + size - 4 while running the main loop. This way
 	 * we can compare for equality to determine when exit the loop.
 	 */
 	addl	%esi, %edi
 	subl	$4, %edi

 	/* Read in the first four aligned bytes. */
 	movl	(%esi), %ecx

 .L_loop:
 	xorl	%eax, %ecx
 	movzbl	%cl, %ebp
 	movl	0x1800(%ebx, %ebp, 8), %eax
 	xorl	%edx, %eax
 	movl	0x1804(%ebx, %ebp, 8), %edx
 	movzbl	%ch, %ebp
 	xorl	0x1000(%ebx, %ebp, 8), %eax
 	xorl	0x1004(%ebx, %ebp, 8), %edx
 	shrl	$16, %ecx
 	movzbl	%cl, %ebp
 	xorl	0x0800(%ebx, %ebp, 8), %eax
 	xorl	0x0804(%ebx, %ebp, 8), %edx
 	movzbl	%ch, %ebp
 	addl	$4, %esi
 	xorl	(%ebx, %ebp, 8), %eax
 	xorl	4(%ebx, %ebp, 8), %edx

 	/* Check for end of aligned input. */
 	cmpl	%edi, %esi

 	/*
 	 * Copy the next input byte to %ecx. It is slightly faster to
 	 * read it here than at the top of the loop.
 	 */
 	movl	(%esi), %ecx
 	jb	.L_loop

 	/*
 	 * Process the remaining four bytes, which we have already
 	 * copied to %ecx.
 	 */
 	xorl	%eax, %ecx
 	movzbl	%cl, %ebp
 	movl	0x1800(%ebx, %ebp, 8), %eax
 	xorl	%edx, %eax
 	movl	0x1804(%ebx, %ebp, 8), %edx
 	movzbl	%ch, %ebp
 	xorl	0x1000(%ebx, %ebp, 8), %eax
 	xorl	0x1004(%ebx, %ebp, 8), %edx
 	shrl	$16, %ecx
 	movzbl	%cl, %ebp
 	xorl	0x0800(%ebx, %ebp, 8), %eax
 	xorl	0x0804(%ebx, %ebp, 8), %edx
 	movzbl	%ch, %ebp
 	addl	$4, %esi
 	xorl	(%ebx, %ebp, 8), %eax
 	xorl	4(%ebx, %ebp, 8), %edx

 	/* Copy the number of remaining bytes to %edi. */
 	movl	0x18(%esp), %edi

 .L_rest:
 	/* Check for end of input. */
 	testl	%edi, %edi
 	jz	.L_return

 	/* Calculate CRC of the next input byte. */
 	movzbl	(%esi), %ebp
 	incl	%esi
 	movzbl	%al, %ecx
 	xorl	%ecx, %ebp
 	shrdl	$8, %edx, %eax
 	xorl	(%ebx, %ebp, 8), %eax
 	shrl	$8, %edx
 	xorl	4(%ebx, %ebp, 8), %edx
 	decl	%edi
 	jmp	.L_rest

 .L_return:
 	/* Complement the final value. */
 	notl	%eax
 	notl	%edx

 	popl	%ebp
 	popl	%edi
 	popl	%esi
 	popl	%ebx
 	ret

 #if defined(PIC) || defined(__PIC__)
 	ALIGN(4, 16)
 .L_get_pc:
 	movl	(%esp), %ebx
 	ret
 #endif

 #if defined(__APPLE__) && (defined(PIC) || defined(__PIC__))
 	/* Mach-O PIC */
 	.section __IMPORT,__pointers,non_lazy_symbol_pointers
 .L_lzma_crc64_table$non_lazy_ptr:
 	.indirect_symbol LZMA_CRC64_TABLE
 	.long 0

 #elif defined(_WIN32) || defined(__CYGWIN__)
 #	ifdef DLL_EXPORT
 	/* This is equivalent of __declspec(dllexport). */
 	.section .drectve
 	.ascii " -export:lzma_crc64"
 #	endif

 #elif !defined(__MSDOS__)
 	/* ELF */
 	.size	LZMA_CRC64, .-LZMA_CRC64
 #endif

 /*
  * This is needed to support non-executable stack. It's ugly to
  * use __linux__ here, but I don't know a way to detect when
  * we are using GNU assembler.
  */
 #if defined(__ELF__) && defined(__linux__)
 	.section	.note.GNU-stack,"",@progbits
 #endif
	/*
	* Speed-optimized CRC64 using slicing-by-four algorithm
	*
	* This uses only i386 instructions, but it is optimized for i686 and later
	* (including e.g. Pentium II/III/IV, Athlon XP, and Core 2).
	*
	* Authors: Igor Pavlov (original CRC32 assembly code)
	* Lasse Collin (CRC64 adaptation of the modified CRC32 code)
	*
	* This file has been put into the public domain.
	* You can do whatever you want with this file.
	*
	* This code needs lzma_crc64_table, which can be created using the
	* following C code:

	uint64_t lzma_crc64_table[4][256];

	void
	init_table(void)
	{
	// ECMA-182
	static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);

	for (size_t s = 0; s < 4; ++s) {
	for (size_t b = 0; b < 256; ++b) {
	uint64_t r = s == 0 ? b : lzma_crc64_table[s - 1][b];

	for (size_t i = 0; i < 8; ++i) {
	if (r & 1)
	r = (r >> 1) ^ poly64;
	else
	r >>= 1;
	}

	lzma_crc64_table[s][b] = r;
	}
	}
	}

	* The prototype of the CRC64 function:
	* extern uint64_t lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc);
	*/

	/*
	* On some systems, the functions need to be prefixed. The prefix is
	* usually an underscore.
	*/
	#ifndef __USER_LABEL_PREFIX__
	# define __USER_LABEL_PREFIX__
	#endif
	#define MAKE_SYM_CAT(prefix, sym) prefix ## sym
	#define MAKE_SYM(prefix, sym) MAKE_SYM_CAT(prefix, sym)
	#define LZMA_CRC64 MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64)
	#define LZMA_CRC64_TABLE MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc64_table)

	/*
	* Solaris assembler doesn't have .p2align, and Darwin uses .align
	* differently than GNU/Linux and Solaris.
	*/
	#if defined(__APPLE__) \|\| defined(__MSDOS__)
	# define ALIGN(pow2, abs) .align pow2
	#else
	# define ALIGN(pow2, abs) .align abs
	#endif

	.text
	.globl LZMA_CRC64

	#if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) \
	&& !defined(__MSDOS__)
	.type LZMA_CRC64, @function
	#endif

	ALIGN(4, 16)
	LZMA_CRC64:
	/*
	* Register usage:
	* %eax crc LSB
	* %edx crc MSB
	* %esi buf
	* %edi size or buf + size
	* %ebx lzma_crc64_table
	* %ebp Table index
	* %ecx Temporary
	*/
	pushl %ebx
	pushl %esi
	pushl %edi
	pushl %ebp
	movl 0x14(%esp), %esi /* buf */
	movl 0x18(%esp), %edi /* size */
	movl 0x1C(%esp), %eax /* crc LSB */
	movl 0x20(%esp), %edx /* crc MSB */

	/*
	* Store the address of lzma_crc64_table to %ebx. This is needed to
	* get position-independent code (PIC).
	*
	* The PIC macro is defined by libtool, while __PIC__ is defined
	* by GCC but only on some systems. Testing for both makes it simpler
	* to test this code without libtool, and keeps the code working also
	* when built with libtool but using something else than GCC.
	*
	* I understood that libtool may define PIC on Windows even though
	* the code in Windows DLLs is not PIC in sense that it is in ELF
	* binaries, so we need a separate check to always use the non-PIC
	* code on Windows.
	*/
	#if (!defined(PIC) && !defined(__PIC__)) \
	\|\| (defined(_WIN32) \|\| defined(__CYGWIN__))
	/* Not PIC */
	movl $ LZMA_CRC64_TABLE, %ebx
	#elif defined(__APPLE__)
	/* Mach-O */
	call .L_get_pc
	.L_pic:
	leal .L_lzma_crc64_table$non_lazy_ptr-.L_pic(%ebx), %ebx
	movl (%ebx), %ebx
	#else
	/* ELF */
	call .L_get_pc
	addl $_GLOBAL_OFFSET_TABLE_, %ebx
	movl LZMA_CRC64_TABLE@GOT(%ebx), %ebx
	#endif

	/* Complement the initial value. */
	notl %eax
	notl %edx

	.L_align:
	/*
	* Check if there is enough input to use slicing-by-four.
	* We need eight bytes, because the loop pre-reads four bytes.
	*/
	cmpl $8, %edi
	jb .L_rest

	/* Check if we have reached alignment of four bytes. */
	testl $3, %esi
	jz .L_slice

	/* Calculate CRC of the next input byte. */
	movzbl (%esi), %ebp
	incl %esi
	movzbl %al, %ecx
	xorl %ecx, %ebp
	shrdl $8, %edx, %eax
	xorl (%ebx, %ebp, 8), %eax
	shrl $8, %edx
	xorl 4(%ebx, %ebp, 8), %edx
	decl %edi
	jmp .L_align

	.L_slice:
	/*
	* If we get here, there's at least eight bytes of aligned input
	* available. Make %edi multiple of four bytes. Store the possible
	* remainder over the "size" variable in the argument stack.
	*/
	movl %edi, 0x18(%esp)
	andl $-4, %edi
	subl %edi, 0x18(%esp)

	/*
	* Let %edi be buf + size - 4 while running the main loop. This way
	* we can compare for equality to determine when exit the loop.
	*/
	addl %esi, %edi
	subl $4, %edi

	/* Read in the first four aligned bytes. */
	movl (%esi), %ecx

	.L_loop:
	xorl %eax, %ecx
	movzbl %cl, %ebp
	movl 0x1800(%ebx, %ebp, 8), %eax
	xorl %edx, %eax
	movl 0x1804(%ebx, %ebp, 8), %edx
	movzbl %ch, %ebp
	xorl 0x1000(%ebx, %ebp, 8), %eax
	xorl 0x1004(%ebx, %ebp, 8), %edx
	shrl $16, %ecx
	movzbl %cl, %ebp
	xorl 0x0800(%ebx, %ebp, 8), %eax
	xorl 0x0804(%ebx, %ebp, 8), %edx
	movzbl %ch, %ebp
	addl $4, %esi
	xorl (%ebx, %ebp, 8), %eax
	xorl 4(%ebx, %ebp, 8), %edx

	/* Check for end of aligned input. */
	cmpl %edi, %esi

	/*
	* Copy the next input byte to %ecx. It is slightly faster to
	* read it here than at the top of the loop.
	*/
	movl (%esi), %ecx
	jb .L_loop

	/*
	* Process the remaining four bytes, which we have already
	* copied to %ecx.
	*/
	xorl %eax, %ecx
	movzbl %cl, %ebp
	movl 0x1800(%ebx, %ebp, 8), %eax
	xorl %edx, %eax
	movl 0x1804(%ebx, %ebp, 8), %edx
	movzbl %ch, %ebp
	xorl 0x1000(%ebx, %ebp, 8), %eax
	xorl 0x1004(%ebx, %ebp, 8), %edx
	shrl $16, %ecx
	movzbl %cl, %ebp
	xorl 0x0800(%ebx, %ebp, 8), %eax
	xorl 0x0804(%ebx, %ebp, 8), %edx
	movzbl %ch, %ebp
	addl $4, %esi
	xorl (%ebx, %ebp, 8), %eax
	xorl 4(%ebx, %ebp, 8), %edx

	/* Copy the number of remaining bytes to %edi. */
	movl 0x18(%esp), %edi

	.L_rest:
	/* Check for end of input. */
	testl %edi, %edi
	jz .L_return

	/* Calculate CRC of the next input byte. */
	movzbl (%esi), %ebp
	incl %esi
	movzbl %al, %ecx
	xorl %ecx, %ebp
	shrdl $8, %edx, %eax
	xorl (%ebx, %ebp, 8), %eax
	shrl $8, %edx
	xorl 4(%ebx, %ebp, 8), %edx
	decl %edi
	jmp .L_rest

	.L_return:
	/* Complement the final value. */
	notl %eax
	notl %edx

	popl %ebp
	popl %edi
	popl %esi
	popl %ebx
	ret

	#if defined(PIC) \|\| defined(__PIC__)
	ALIGN(4, 16)
	.L_get_pc:
	movl (%esp), %ebx
	ret
	#endif

	#if defined(__APPLE__) && (defined(PIC) \|\| defined(__PIC__))
	/* Mach-O PIC */
	.section __IMPORT,__pointers,non_lazy_symbol_pointers
	.L_lzma_crc64_table$non_lazy_ptr:
	.indirect_symbol LZMA_CRC64_TABLE
	.long 0

	#elif defined(_WIN32) \|\| defined(__CYGWIN__)
	# ifdef DLL_EXPORT
	/* This is equivalent of __declspec(dllexport). */
	.section .drectve
	.ascii " -export:lzma_crc64"
	# endif

	#elif !defined(__MSDOS__)
	/* ELF */
	.size LZMA_CRC64, .-LZMA_CRC64
	#endif

	/*
	* This is needed to support non-executable stack. It's ugly to
	* use __linux__ here, but I don't know a way to detect when
	* we are using GNU assembler.
	*/
	#if defined(__ELF__) && defined(__linux__)
	.section .note.GNU-stack,"",@progbits
	#endif