diff options
| author |  Arkady Shapkin <arkady.shapkin@gmail.com> | 2018-02-15 02:23:30 +0300 |
|---|---|---|
| committer | Arkady Shapkin <arkady.shapkin@gmail.com> | 2018-02-15 02:37:42 +0300 |
| commit | 22c477d91051f029d96b2078e41b74a15135cc58 (patch) | |
| tree | 1548b580fd01e93d25529ca780418401e977f071 /src/google/protobuf/stubs/port.h | |
| parent | e34ec6077af141dd5dfc1c334ecdcce3c6b51612 (diff) | |
Support using MSVC intrinsics in Log2FloorNonZero
Diffstat (limited to 'src/google/protobuf/stubs/port.h')
| -rw-r--r-- | src/google/protobuf/stubs/port.h | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/google/protobuf/stubs/port.h b/src/google/protobuf/stubs/port.h index 27849298..4597c6cf 100644 --- a/src/google/protobuf/stubs/port.h +++ b/src/google/protobuf/stubs/port.h @@ -91,6 +91,7 @@ // These #includes are for the byte swap functions declared later on. #ifdef _MSC_VER #include <stdlib.h> // NOLINT(build/include) +#include <intrin.h> #elif defined(__APPLE__) #include <libkern/OSByteOrder.h> #elif defined(__GLIBC__) || defined(__CYGWIN__) @@ -394,12 +395,10 @@ class Bits { static uint32 Log2FloorNonZero(uint32 n) { #if defined(__GNUC__) return 31 ^ static_cast<uint32>(__builtin_clz(n)); -#elif defined(COMPILER_MSVC) && defined(_M_IX86) - _asm { - bsr ebx, n - mov n, ebx - } - return n; +#elif defined(_MSC_VER) + unsigned long where; + _BitScanReverse(&where, n); + return where; #else return Log2FloorNonZero_Portable(n); #endif @@ -414,6 +413,10 @@ class Bits { // implementation instead. #if defined(__GNUC__) && !defined(GOOGLE_PROTOBUF_USE_PORTABLE_LOG2) return 63 ^ static_cast<uint32>(__builtin_clzll(n)); +#elif defined(_MSC_VER) && defined(_M_X64) + unsigned long where; + _BitScanReverse64(&where, n); + return where; #else return Log2FloorNonZero64_Portable(n); #endif |