From e0ce60c744f0ebea16bd6a1665f23ccf4461c7c3 Mon Sep 17 00:00:00 2001 From: Angel Pons Date: Wed, 14 Oct 2020 17:48:05 +0200 Subject: lib and libpayload: Add popcnt functions Add 32-bit `popcnt` and 64-bit `popcnt64` helpers. Change-Id: I2e6a1007e475b662a85c067d96f81326e7f02905 Signed-off-by: Angel Pons Reviewed-on: https://review.coreboot.org/c/coreboot/+/46421 Tested-by: build bot (Jenkins) Reviewed-by: Tim Wawrzynczak --- payloads/libpayload/include/libpayload.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'payloads') diff --git a/payloads/libpayload/include/libpayload.h b/payloads/libpayload/include/libpayload.h index 475fe0f3fc..b761f042b9 100644 --- a/payloads/libpayload/include/libpayload.h +++ b/payloads/libpayload/include/libpayload.h @@ -445,6 +445,8 @@ u8 hex2bin(u8 h); void hexdump(const void *memory, size_t length); void fatal(const char *msg) __attribute__((noreturn)); +/* Population Count: number of bits that are one */ +static inline int popcnt(u32 x) { return __builtin_popcount(x); } /* Count Leading Zeroes: clz(0) == 32, clz(0xf) == 28, clz(1 << 31) == 0 */ static inline int clz(u32 x) { @@ -455,6 +457,7 @@ 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 popcnt64(u64 x) { return __builtin_popcountll(x); } static inline int clz64(u64 x) { return x ? __builtin_clzll(x) : sizeof(x) * 8; -- cgit v1.2.3