// SPDX-License-Identifier: GPL-2.0 /* * MSB0 numbered special bitops handling. * * The bits are numbered: * |0..............63|64............127|128...........191|192...........255| * * The reason for this bit numbering is the fact that the hardware sets bits * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap * from the 'wrong end'. */ #include <linux/compiler.h> #include <linux/bitops.h> #include <linux/export.h> unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size) { const unsigned long *p = addr; unsigned long result = 0; unsigned long tmp; while (size & ~(BITS_PER_LONG - 1)) { if ((tmp = *(p++))) goto found; result += BITS_PER_LONG; size -= BITS_PER_LONG; } if (!size) return result; tmp = (*p) & (~0UL << (BITS_PER_LONG - size)); if (!tmp) /* Are any bits set? */ return result + size; /* Nope. */ found: return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); } EXPORT_SYMBOL(find_first_bit_inv); unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size, unsigned long offset) { const unsigned long *p = addr + (offset / BITS_PER_LONG); unsigned long result = offset & ~(BITS_PER_LONG - 1); unsigned long tmp; if (offset >= size) return size; size -= result; offset %= BITS_PER_LONG; if (offset) { tmp = *(p++); tmp &= (~0UL >> offset); if (size < BITS_PER_LONG) goto found_first; if (tmp) goto found_middle; size -= BITS_PER_LONG; result += BITS_PER_LONG; } while (size & ~(BITS_PER_LONG-1)) { if ((tmp = *(p++))) goto found_middle; result += BITS_PER_LONG; size -= BITS_PER_LONG; } if (!size) return result; tmp = *p; found_first: tmp &= (~0UL << (BITS_PER_LONG - size)); if (!tmp) /* Are any bits set? */ return result + size; /* Nope. */ found_middle: return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); } EXPORT_SYMBOL(find_next_bit_inv);