diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | lib/ffsl.c | 1 | ||||
| -rw-r--r-- | lib/ffsl.h | 8 | ||||
| -rw-r--r-- | lib/ffsll.c | 3 |
4 files changed, 19 insertions, 0 deletions
@@ -1,5 +1,12 @@ 2020-08-03 Bruno Haible <bruno@clisp.org> + ffsll: Optimize for MSVC in 64-bit mode. + * lib/ffsl.h (FUNC): On MSVC, use MSVC_BUILTIN if defined. + * lib/ffsll.c (MSVC_BUILTIN): Define for MSVC in 64-bit mode. + * lib/ffsl.c (MSVC_BUILTIN): Define for MSVC. + +2020-08-03 Bruno Haible <bruno@clisp.org> + ffsll: Optimize for MSVC in 32-bit mode. * lib/ffsl.h: Include <intrin.h>. (ffs): Define as inline function, like in lib/ffs.c. diff --git a/lib/ffsl.c b/lib/ffsl.c index ee99ba7e01..198cacbd88 100644 --- a/lib/ffsl.c +++ b/lib/ffsl.c @@ -1,4 +1,5 @@ #define FUNC ffsl #define TYPE long int #define GCC_BUILTIN __builtin_ffsl +#define MSVC_BUILTIN _BitScanForward #include "ffsl.h" diff --git a/lib/ffsl.h b/lib/ffsl.h index d5c5a97509..fa5c0935a3 100644 --- a/lib/ffsl.h +++ b/lib/ffsl.h @@ -52,6 +52,14 @@ FUNC (TYPE i) { #if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) && defined GCC_BUILTIN return GCC_BUILTIN (i); +#elif defined _MSC_VER && defined MSVC_BUILTIN + /* _BitScanForward, _BitScanForward64 + <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64> */ + unsigned long bit; + if (MSVC_BUILTIN (&bit, i)) + return bit + 1; + else + return 0; #else unsigned TYPE j = i; /* Split j into chunks, and look at one chunk after the other. */ diff --git a/lib/ffsll.c b/lib/ffsll.c index f0e9425eed..80a273c3b3 100644 --- a/lib/ffsll.c +++ b/lib/ffsll.c @@ -1,4 +1,7 @@ #define FUNC ffsll #define TYPE long long int #define GCC_BUILTIN __builtin_ffsll +#ifdef _WIN64 +# define MSVC_BUILTIN _BitScanForward64 +#endif #include "ffsl.h" |