diff options
| author | Tillmann Karras <tilkax@gmail.com> | 2013-10-24 22:05:53 +0200 |
|---|---|---|
| committer | Tillmann Karras <tilkax@gmail.com> | 2013-11-13 06:24:58 +0100 |
| commit | cd069fdce1bd7a30f99f3bed9dfe0af60cd562d8 (patch) | |
| tree | bbc527f22fa5303c21b9bd36d57deb89e42c1a2d /Source/Core/Common/Src/x64CPUDetect.cpp | |
| parent | 466a7afde336d381e250d51e4c268c769e072a02 (diff) | |
Interpreter: software-based flush-to-zero
bDAZ is now called bFlushToZero to better reflect what it's actually
used for.
I decided not to support any hardware-based flush-to-zero on systems
that don't support this for both inputs _and_ outputs. It makes the code
cleaner and the intersection of CPUs that support SSE2 but not DAZ
should be very small.
Diffstat (limited to 'Source/Core/Common/Src/x64CPUDetect.cpp')
| -rw-r--r-- | Source/Core/Common/Src/x64CPUDetect.cpp | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/Source/Core/Common/Src/x64CPUDetect.cpp b/Source/Core/Common/Src/x64CPUDetect.cpp index 182cca5224..d6f36eb142 100644 --- a/Source/Core/Common/Src/x64CPUDetect.cpp +++ b/Source/Core/Common/Src/x64CPUDetect.cpp @@ -162,6 +162,7 @@ void CPUInfo::Detect() if ((cpu_id[2] >> 20) & 1) bSSE4_2 = true; if ((cpu_id[2] >> 25) & 1) bAES = true; + // To check DAZ support, we first need to check FXSAVE support. if ((cpu_id[3] >> 24) & 1) { // We can use FXSAVE. @@ -181,7 +182,12 @@ void CPUInfo::Detect() // lowest byte of MXCSR_MASK if ((fx_state[0x1C] >> 6) & 1) - bDAZ = true; + { + // On x86, the FTZ field (supported since SSE1) only flushes denormal _outputs_ to zero, + // now that we checked DAZ support (flushing denormal _inputs_ to zero), + // we can set our generic flag. + bFlushToZero = true; + } } // AVX support requires 3 separate checks: |