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lib and libpayload: add 64-bit versions of clz, __ffs and log2 

Add 64-bit versions of clz, __ffs & log2: `__ffs64`, `__clz64`,
and `log2_64`.

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: Iefc6e6c51f5b20607c88e38660a499a4f77ce0d0
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45938
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
This commit is contained in:
Tim Wawrzynczak 2020-10-01 15:36:42 -06:00 committed by Angel Pons
parent 7223bfa47e
commit 7ded1afe0a
2 changed files with 12 additions and 0 deletions
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8
payloads/libpayload/include/libpayload.h
View File

@ -454,6 +454,14 @@ static inline int clz(u32 x)
static inline int log2(u32 x) { return (int)sizeof(x) * 8 - clz(x) - 1; }
/* Find First Set: __ffs(0xf) == 0, __ffs(0) == -1, __ffs(1 << 31) == 31 */
static inline int __ffs(u32 x) { return log2(x & (u32)(-(s32)x)); }
static inline int clz64(u64 x)
{
return x ? __builtin_clzll(x) : sizeof(x) * 8;
}
static inline int log2_64(u64 x) { return sizeof(x) * 8 - clz64(x) - 1; }
static inline int __ffs64(u64 x) { return log2_64(x & (u64)(-(s64)x)); }
/** @} */
/**

4
src/include/lib.h
View File

@ -56,4 +56,8 @@ static inline int __ffs(u32 x) { return log2(x & (u32)(-(s32)x)); }
/* Integer binary logarithm (rounding up): log2_ceil(0) == -1, log2(5) == 3 */
static inline int log2_ceil(u32 x) { return (x == 0) ? -1 : log2(x * 2 - 1); }
static inline int clz64(u64 x) { return x ? __builtin_clzll(x) : sizeof(x) * 8; }
static inline int log2_64(u64 x) { return sizeof(x) * 8 - clz64(x) - 1; }
static inline int __ffs64(u64 x) { return log2_64(x & (u64)(-(s64)x)); }
#endif /* __LIB_H__ */