mirror of
https://github.com/yuzu-emu/unicorn
synced 2024-11-24 08:28:35 +00:00
129 lines
3.2 KiB
C
129 lines
3.2 KiB
C
/*
|
|
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
* Copyright (C) 2008 IBM Corporation
|
|
* Written by Rusty Russell <rusty@rustcorp.com.au>
|
|
* (Inspired by David Howell's find_next_bit implementation)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#include "qemu/bitops.h"
|
|
|
|
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
|
|
|
|
/*
|
|
* Find the next set bit in a memory region.
|
|
*/
|
|
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
|
|
unsigned long offset)
|
|
{
|
|
const unsigned long *p = addr + BITOP_WORD(offset);
|
|
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 >= 4*BITS_PER_LONG) {
|
|
unsigned long d1, d2, d3;
|
|
tmp = *p;
|
|
d1 = *(p+1);
|
|
d2 = *(p+2);
|
|
d3 = *(p+3);
|
|
if (tmp) {
|
|
goto found_middle;
|
|
}
|
|
if (d1 | d2 | d3) {
|
|
break;
|
|
}
|
|
p += 4;
|
|
result += 4*BITS_PER_LONG;
|
|
size -= 4*BITS_PER_LONG;
|
|
}
|
|
while (size >= BITS_PER_LONG) {
|
|
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 == 0UL) { /* Are any bits set? */
|
|
return result + size; /* Nope. */
|
|
}
|
|
found_middle:
|
|
return result + ctzl(tmp);
|
|
}
|
|
|
|
/*
|
|
* This implementation of find_{first,next}_zero_bit was stolen from
|
|
* Linus' asm-alpha/bitops.h.
|
|
*/
|
|
unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
|
|
unsigned long offset)
|
|
{
|
|
const unsigned long *p = addr + BITOP_WORD(offset);
|
|
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 >> (BITS_PER_LONG - 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 << size;
|
|
if (tmp == ~0UL) { /* Are any bits zero? */
|
|
return result + size; /* Nope. */
|
|
}
|
|
found_middle:
|
|
return result + ctzl(~tmp);
|
|
}
|