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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [x86/] [lib/] [bitops_64.c] - Rev 3
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#include <linux/bitops.h> #undef find_first_zero_bit #undef find_next_zero_bit #undef find_first_bit #undef find_next_bit static inline long __find_first_zero_bit(const unsigned long * addr, unsigned long size) { long d0, d1, d2; long res; /* * We must test the size in words, not in bits, because * otherwise incoming sizes in the range -63..-1 will not run * any scasq instructions, and then the flags used by the je * instruction will have whatever random value was in place * before. Nobody should call us like that, but * find_next_zero_bit() does when offset and size are at the * same word and it fails to find a zero itself. */ size += 63; size >>= 6; if (!size) return 0; asm volatile( " repe; scasq\n" " je 1f\n" " xorq -8(%%rdi),%%rax\n" " subq $8,%%rdi\n" " bsfq %%rax,%%rdx\n" "1: subq %[addr],%%rdi\n" " shlq $3,%%rdi\n" " addq %%rdi,%%rdx" :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2) :"0" (0ULL), "1" (size), "2" (addr), "3" (-1ULL), [addr] "S" (addr) : "memory"); /* * Any register would do for [addr] above, but GCC tends to * prefer rbx over rsi, even though rsi is readily available * and doesn't have to be saved. */ return res; } /** * find_first_zero_bit - find the first zero bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit-number of the first zero bit, not the number of the byte * containing a bit. */ long find_first_zero_bit(const unsigned long * addr, unsigned long size) { return __find_first_zero_bit (addr, size); } /** * find_next_zero_bit - find the first zero bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The maximum size to search */ long find_next_zero_bit (const unsigned long * addr, long size, long offset) { const unsigned long * p = addr + (offset >> 6); unsigned long set = 0; unsigned long res, bit = offset&63; if (bit) { /* * Look for zero in first word */ asm("bsfq %1,%0\n\t" "cmoveq %2,%0" : "=r" (set) : "r" (~(*p >> bit)), "r"(64L)); if (set < (64 - bit)) return set + offset; set = 64 - bit; p++; } /* * No zero yet, search remaining full words for a zero */ res = __find_first_zero_bit (p, size - 64 * (p - addr)); return (offset + set + res); } static inline long __find_first_bit(const unsigned long * addr, unsigned long size) { long d0, d1; long res; /* * We must test the size in words, not in bits, because * otherwise incoming sizes in the range -63..-1 will not run * any scasq instructions, and then the flags used by the jz * instruction will have whatever random value was in place * before. Nobody should call us like that, but * find_next_bit() does when offset and size are at the same * word and it fails to find a one itself. */ size += 63; size >>= 6; if (!size) return 0; asm volatile( " repe; scasq\n" " jz 1f\n" " subq $8,%%rdi\n" " bsfq (%%rdi),%%rax\n" "1: subq %[addr],%%rdi\n" " shlq $3,%%rdi\n" " addq %%rdi,%%rax" :"=a" (res), "=&c" (d0), "=&D" (d1) :"0" (0ULL), "1" (size), "2" (addr), [addr] "r" (addr) : "memory"); return res; } /** * find_first_bit - find the first set bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit-number of the first set bit, not the number of the byte * containing a bit. */ long find_first_bit(const unsigned long * addr, unsigned long size) { return __find_first_bit(addr,size); } /** * find_next_bit - find the first set bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The maximum size to search */ long find_next_bit(const unsigned long * addr, long size, long offset) { const unsigned long * p = addr + (offset >> 6); unsigned long set = 0, bit = offset & 63, res; if (bit) { /* * Look for nonzero in the first 64 bits: */ asm("bsfq %1,%0\n\t" "cmoveq %2,%0\n\t" : "=r" (set) : "r" (*p >> bit), "r" (64L)); if (set < (64 - bit)) return set + offset; set = 64 - bit; p++; } /* * No set bit yet, search remaining full words for a bit */ res = __find_first_bit (p, size - 64 * (p - addr)); return (offset + set + res); } #include <linux/module.h> EXPORT_SYMBOL(find_next_bit); EXPORT_SYMBOL(find_first_bit); EXPORT_SYMBOL(find_first_zero_bit); EXPORT_SYMBOL(find_next_zero_bit);