From 73d97b7dc492871d3dcf4ee919fc443dd2308dec Mon Sep 17 00:00:00 2001 From: Vas Crabb Date: Sat, 12 Jun 2021 03:00:21 +1000 Subject: Added helpers for 64-bit count leading zeroes/ones. --- src/osd/eigccarm.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 54 insertions(+), 8 deletions(-) (limited to 'src/osd/eigccarm.h') diff --git a/src/osd/eigccarm.h b/src/osd/eigccarm.h index 27d79c4a5c6..90004daf9d4 100644 --- a/src/osd/eigccarm.h +++ b/src/osd/eigccarm.h @@ -239,14 +239,14 @@ _mulu_64x64(uint64_t a, uint64_t b, uint64_t &hi) ***************************************************************************/ /*------------------------------------------------- - count_leading_zeros - return the number of + count_leading_zeros_32 - return the number of leading zero bits in a 32-bit value -------------------------------------------------*/ #if defined(__aarch64__) -#define count_leading_zeros _count_leading_zeros +#define count_leading_zeros_32 _count_leading_zeros_32 inline uint8_t ATTR_CONST ATTR_FORCE_INLINE -_count_leading_zeros(uint32_t value) +_count_leading_zeros_32(uint32_t value) { uint32_t result; @@ -256,20 +256,20 @@ _count_leading_zeros(uint32_t value) : [value] "r" (value) ); - return result; + return uint8_t(result); } #endif /*------------------------------------------------- - count_leading_ones - return the number of + count_leading_ones_32 - return the number of leading one bits in a 32-bit value -------------------------------------------------*/ #if defined(__aarch64__) -#define count_leading_ones _count_leading_ones +#define count_leading_ones_32 _count_leading_ones_32 inline uint8_t ATTR_CONST ATTR_FORCE_INLINE -_count_leading_ones(uint32_t value) +_count_leading_ones_32(uint32_t value) { uint32_t result; @@ -279,7 +279,53 @@ _count_leading_ones(uint32_t value) : [value] "r" (~value) ); - return result; + return uint8_t(result); +} +#endif + + +/*------------------------------------------------- + count_leading_zeros_64 - return the number of + leading zero bits in a 64-bit value +-------------------------------------------------*/ + +#if defined(__aarch64__) +#define count_leading_zeros_64 _count_leading_zeros_64 +inline uint8_t ATTR_CONST ATTR_FORCE_INLINE +_count_leading_zeros_64(uint64_t value) +{ + uint64_t result; + + __asm__ ( + " clz %[result], %[value] \n" + : [result] "=r" (result) + : [value] "r" (value) + ); + + return uint8_t(result); +} +#endif + + +/*------------------------------------------------- + count_leading_ones_64 - return the number of + leading one bits in a 64-bit value +-------------------------------------------------*/ + +#if defined(__aarch64__) +#define count_leading_ones_64 _count_leading_ones_64 +inline uint8_t ATTR_CONST ATTR_FORCE_INLINE +_count_leading_ones_64(uint64_t value) +{ + uint64_t result; + + __asm__ ( + " clz %[result], %[value] \n" + : [result] "=r" (result) + : [value] "r" (~value) + ); + + return uint8_t(result); } #endif -- cgit v1.2.3-70-g09d2