Index: xz/src/liblzma/check/crc32_x86.S |
=================================================================== |
--- xz/src/liblzma/check/crc32_x86.S (revision 0) |
+++ xz/src/liblzma/check/crc32_x86.S (revision 0) |
@@ -0,0 +1,304 @@ |
+/* |
+ * Speed-optimized CRC32 using slicing-by-eight 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). For i586 |
+ * (e.g. Pentium), slicing-by-four would be better, and even the C version |
+ * of slicing-by-eight built with gcc -march=i586 tends to be a little bit |
+ * better than this. Very few probably run this code on i586 or older x86 |
+ * so this shouldn't be a problem in practice. |
+ * |
+ * Authors: Igor Pavlov (original version) |
+ * Lasse Collin (AT&T syntax, PIC support, better portability) |
+ * |
+ * This file has been put into the public domain. |
+ * You can do whatever you want with this file. |
+ * |
+ * This code needs lzma_crc32_table, which can be created using the |
+ * following C code: |
+ |
+uint32_t lzma_crc32_table[8][256]; |
+ |
+void |
+init_table(void) |
+{ |
+ // IEEE-802.3 |
+ static const uint32_t poly32 = UINT32_C(0xEDB88320); |
+ |
+ // Castagnoli |
+ // static const uint32_t poly32 = UINT32_C(0x82F63B78); |
+ |
+ // Koopman |
+ // static const uint32_t poly32 = UINT32_C(0xEB31D82E); |
+ |
+ for (size_t s = 0; s < 8; ++s) { |
+ for (size_t b = 0; b < 256; ++b) { |
+ uint32_t r = s == 0 ? b : lzma_crc32_table[s - 1][b]; |
+ |
+ for (size_t i = 0; i < 8; ++i) { |
+ if (r & 1) |
+ r = (r >> 1) ^ poly32; |
+ else |
+ r >>= 1; |
+ } |
+ |
+ lzma_crc32_table[s][b] = r; |
+ } |
+ } |
+} |
+ |
+ * The prototype of the CRC32 function: |
+ * extern uint32_t lzma_crc32(const uint8_t *buf, size_t size, uint32_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_CRC32 MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc32) |
+#define LZMA_CRC32_TABLE MAKE_SYM(__USER_LABEL_PREFIX__, lzma_crc32_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_CRC32 |
+ |
+#if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) \ |
+ && !defined(__MSDOS__) |
+ .type LZMA_CRC32, @function |
+#endif |
+ |
+ ALIGN(4, 16) |
+LZMA_CRC32: |
+ /* |
+ * Register usage: |
+ * %eax crc |
+ * %esi buf |
+ * %edi size or buf + size |
+ * %ebx lzma_crc32_table |
+ * %ebp Table index |
+ * %ecx Temporary |
+ * %edx Temporary |
+ */ |
+ pushl %ebx |
+ pushl %esi |
+ pushl %edi |
+ pushl %ebp |
+ movl 0x14(%esp), %esi /* buf */ |
+ movl 0x18(%esp), %edi /* size */ |
+ movl 0x1C(%esp), %eax /* crc */ |
+ |
+ /* |
+ * Store the address of lzma_crc32_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_CRC32_TABLE, %ebx |
+#elif defined(__APPLE__) |
+ /* Mach-O */ |
+ call .L_get_pc |
+.L_pic: |
+ leal .L_lzma_crc32_table$non_lazy_ptr-.L_pic(%ebx), %ebx |
+ movl (%ebx), %ebx |
+#else |
+ /* ELF */ |
+ call .L_get_pc |
+ addl $_GLOBAL_OFFSET_TABLE_, %ebx |
+ movl LZMA_CRC32_TABLE@GOT(%ebx), %ebx |
+#endif |
+ |
+ /* Complement the initial value. */ |
+ notl %eax |
+ |
+ ALIGN(4, 16) |
+.L_align: |
+ /* |
+ * Check if there is enough input to use slicing-by-eight. |
+ * We need 16 bytes, because the loop pre-reads eight bytes. |
+ */ |
+ cmpl $16, %edi |
+ jb .L_rest |
+ |
+ /* Check if we have reached alignment of eight bytes. */ |
+ testl $7, %esi |
+ jz .L_slice |
+ |
+ /* Calculate CRC of the next input byte. */ |
+ movzbl (%esi), %ebp |
+ incl %esi |
+ movzbl %al, %ecx |
+ xorl %ecx, %ebp |
+ shrl $8, %eax |
+ xorl (%ebx, %ebp, 4), %eax |
+ decl %edi |
+ jmp .L_align |
+ |
+ ALIGN(2, 4) |
+.L_slice: |
+ /* |
+ * If we get here, there's at least 16 bytes of aligned input |
+ * available. Make %edi multiple of eight bytes. Store the possible |
+ * remainder over the "size" variable in the argument stack. |
+ */ |
+ movl %edi, 0x18(%esp) |
+ andl $-8, %edi |
+ subl %edi, 0x18(%esp) |
+ |
+ /* |
+ * Let %edi be buf + size - 8 while running the main loop. This way |
+ * we can compare for equality to determine when exit the loop. |
+ */ |
+ addl %esi, %edi |
+ subl $8, %edi |
+ |
+ /* Read in the first eight aligned bytes. */ |
+ xorl (%esi), %eax |
+ movl 4(%esi), %ecx |
+ movzbl %cl, %ebp |
+ |
+.L_loop: |
+ movl 0x0C00(%ebx, %ebp, 4), %edx |
+ movzbl %ch, %ebp |
+ xorl 0x0800(%ebx, %ebp, 4), %edx |
+ shrl $16, %ecx |
+ xorl 8(%esi), %edx |
+ movzbl %cl, %ebp |
+ xorl 0x0400(%ebx, %ebp, 4), %edx |
+ movzbl %ch, %ebp |
+ xorl (%ebx, %ebp, 4), %edx |
+ movzbl %al, %ebp |
+ |
+ /* |
+ * Read the next four bytes, for which the CRC is calculated |
+ * on the next interation of the loop. |
+ */ |
+ movl 12(%esi), %ecx |
+ |
+ xorl 0x1C00(%ebx, %ebp, 4), %edx |
+ movzbl %ah, %ebp |
+ shrl $16, %eax |
+ xorl 0x1800(%ebx, %ebp, 4), %edx |
+ movzbl %ah, %ebp |
+ movzbl %al, %eax |
+ movl 0x1400(%ebx, %eax, 4), %eax |
+ addl $8, %esi |
+ xorl %edx, %eax |
+ xorl 0x1000(%ebx, %ebp, 4), %eax |
+ |
+ /* Check for end of aligned input. */ |
+ cmpl %edi, %esi |
+ movzbl %cl, %ebp |
+ jne .L_loop |
+ |
+ /* |
+ * Process the remaining eight bytes, which we have already |
+ * copied to %ecx and %edx. |
+ */ |
+ movl 0x0C00(%ebx, %ebp, 4), %edx |
+ movzbl %ch, %ebp |
+ xorl 0x0800(%ebx, %ebp, 4), %edx |
+ shrl $16, %ecx |
+ movzbl %cl, %ebp |
+ xorl 0x0400(%ebx, %ebp, 4), %edx |
+ movzbl %ch, %ebp |
+ xorl (%ebx, %ebp, 4), %edx |
+ movzbl %al, %ebp |
+ |
+ xorl 0x1C00(%ebx, %ebp, 4), %edx |
+ movzbl %ah, %ebp |
+ shrl $16, %eax |
+ xorl 0x1800(%ebx, %ebp, 4), %edx |
+ movzbl %ah, %ebp |
+ movzbl %al, %eax |
+ movl 0x1400(%ebx, %eax, 4), %eax |
+ addl $8, %esi |
+ xorl %edx, %eax |
+ xorl 0x1000(%ebx, %ebp, 4), %eax |
+ |
+ /* 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 |
+ shrl $8, %eax |
+ xorl (%ebx, %ebp, 4), %eax |
+ decl %edi |
+ jmp .L_rest |
+ |
+.L_return: |
+ /* Complement the final value. */ |
+ notl %eax |
+ |
+ popl %ebp |
+ popl %edi |
+ popl %esi |
+ popl %ebx |
+ ret |
+ |
+#if defined(PIC) || defined(__PIC__) |
+ ALIGN(4, 16) |
+.L_get_pc: |
+ movl (%esp), %ebx |
+ ret |
+#endif |
+ |
+#if defined(__APPLE__) && (defined(PIC) || defined(__PIC__)) |
+ /* Mach-O PIC */ |
+ .section __IMPORT,__pointers,non_lazy_symbol_pointers |
+.L_lzma_crc32_table$non_lazy_ptr: |
+ .indirect_symbol LZMA_CRC32_TABLE |
+ .long 0 |
+ |
+#elif defined(_WIN32) || defined(__CYGWIN__) |
+# ifdef DLL_EXPORT |
+ /* This is equivalent of __declspec(dllexport). */ |
+ .section .drectve |
+ .ascii " -export:lzma_crc32" |
+# endif |
+ |
+#elif !defined(__MSDOS__) |
+ /* ELF */ |
+ .size LZMA_CRC32, .-LZMA_CRC32 |
+#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 |
Property changes on: xz/src/liblzma/check/crc32_x86.S |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |