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[/] [c0or1k/] [trunk/] [src/] [lib/] [bit.c] - Rev 6
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/* * Bit manipulation functions. * * Copyright (C) 2007 Bahadir Balban */ #include <l4/lib/bit.h> #include INC_GLUE(memory.h) /* Emulation of ARM's CLZ (count leading zeroes) instruction */ unsigned int __clz(unsigned int bitvector) { unsigned int x = 0; while((!(bitvector & ((unsigned)1 << 31))) && (x < 32)) { bitvector <<= 1; x++; } return x; } int find_and_set_first_free_bit(u32 *word, unsigned int limit) { int success = 0; int i; for(i = 0; i < limit; i++) { /* Find first unset bit */ if (!(word[BITWISE_GETWORD(i)] & BITWISE_GETBIT(i))) { /* Set it */ word[BITWISE_GETWORD(i)] |= BITWISE_GETBIT(i); success = 1; break; } } /* Return bit just set */ if (success) return i; else return -1; } int check_and_clear_bit(u32 *word, int bit) { /* Check that bit was set */ if (word[BITWISE_GETWORD(bit)] & BITWISE_GETBIT(bit)) { word[BITWISE_GETWORD(bit)] &= ~BITWISE_GETBIT(bit); return 0; } else { //printf("Trying to clear already clear bit\n"); return -1; } } int check_and_set_bit(u32 *word, int bit) { /* Check that bit was clear */ if (!(word[BITWISE_GETWORD(bit)] & BITWISE_GETBIT(bit))) { word[BITWISE_GETWORD(bit)] |= BITWISE_GETBIT(bit); return 0; } else { //printf("Trying to set already set bit\n"); return -1; } }
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