99 lines
1.5 KiB
C
99 lines
1.5 KiB
C
/*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*
|
|
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
|
|
*
|
|
* Authors:
|
|
* Atish Patra<atish.patra@wdc.com>
|
|
*/
|
|
|
|
#ifndef __SBI_BITOPS_H__
|
|
#define __SBI_BITOPS_H__
|
|
|
|
#include <sbi/sbi_bits.h>
|
|
#include <sbi/riscv_asm.h>
|
|
|
|
/**
|
|
* ffs - Find first bit set
|
|
* @x: the word to search
|
|
*
|
|
* This is defined the same way as
|
|
* the libc and compiler builtin ffs routines, therefore
|
|
* differs in spirit from the above ffz (man ffs).
|
|
*/
|
|
static inline int ffs(int x)
|
|
{
|
|
int r = 1;
|
|
|
|
if (!x)
|
|
return 0;
|
|
if (!(x & 0xffff)) {
|
|
x >>= 16;
|
|
r += 16;
|
|
}
|
|
if (!(x & 0xff)) {
|
|
x >>= 8;
|
|
r += 8;
|
|
}
|
|
if (!(x & 0xf)) {
|
|
x >>= 4;
|
|
r += 4;
|
|
}
|
|
if (!(x & 3)) {
|
|
x >>= 2;
|
|
r += 2;
|
|
}
|
|
if (!(x & 1)) {
|
|
x >>= 1;
|
|
r += 1;
|
|
}
|
|
return r;
|
|
}
|
|
|
|
/**
|
|
* __ffs - find first bit in word.
|
|
* @word: The word to search
|
|
*
|
|
* Undefined if no bit exists, so code should check against 0 first.
|
|
*/
|
|
static inline int __ffs(unsigned long word)
|
|
{
|
|
int num = 0;
|
|
|
|
#if BITS_PER_LONG == 64
|
|
if ((word & 0xffffffff) == 0) {
|
|
num += 32;
|
|
word >>= 32;
|
|
}
|
|
#endif
|
|
if ((word & 0xffff) == 0) {
|
|
num += 16;
|
|
word >>= 16;
|
|
}
|
|
if ((word & 0xff) == 0) {
|
|
num += 8;
|
|
word >>= 8;
|
|
}
|
|
if ((word & 0xf) == 0) {
|
|
num += 4;
|
|
word >>= 4;
|
|
}
|
|
if ((word & 0x3) == 0) {
|
|
num += 2;
|
|
word >>= 2;
|
|
}
|
|
if ((word & 0x1) == 0)
|
|
num += 1;
|
|
return num;
|
|
}
|
|
|
|
/*
|
|
* ffz - find first zero in word.
|
|
* @word: The word to search
|
|
*
|
|
* Undefined if no zero exists, so code should check against ~0UL first.
|
|
*/
|
|
#define ffz(x) __ffs(~(x))
|
|
|
|
#endif
|