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lib: Add __fls() (Find Last Set)

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Implement __fls() as an alias for log2(), and remove the duplicate
definitions in commonlib/storage/sdhci.c.

Signed-off-by: Jianjun Wang <jianjun.wang@mediatek.com>
Change-Id: Ib458abfec7e03b2979569a8440a6e69b0285ac32
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59738
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
This commit is contained in:
Jianjun Wang 2021-11-30 10:51:53 +08:00 • committed by Hung-Te Lin
commit 8bb59ca2fa
4 changed files with 19 additions and 32 deletions
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src/include/lib.h
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@ -53,6 +53,8 @@ static inline int clz(u32 x) { return x ? __builtin_clz(x) : sizeof(x) * 8; }
static inline int log2(u32 x) { return sizeof(x) * 8 - clz(x) - 1; }
/* Find First Set: __ffs(1) == 0, __ffs(0) == -1, __ffs(1<<31) == 31 */
static inline int __ffs(u32 x) { return log2(x & (u32)(-(s32)x)); }
/* Find Last Set: __fls(1) == 0, __fls(5) == 2, __fls(1 << 31) == 31 */
static inline int __fls(u32 x) { return log2(x); }
/* Integer binary logarithm (rounding up): log2_ceil(0) == -1, log2_ceil(5) == 3 */
static inline int log2_ceil(u32 x) { return (x == 0) ? -1 : log2(x - 1) + 1; }
@ -61,5 +63,6 @@ static inline int popcnt64(u64 x) { return __builtin_popcountll(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)); }
static inline int __fls64(u64 x) { return log2_64(x); }
#endif /* __LIB_H__ */