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Vertex decoder: fix the jit-match test on MSVC

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The test didn't compile: VERTS is captured by reference into testFormat, and
MSVC won't use a captured constexpr as an array bound. Make it static.

On arm64 it then failed on the UV prescale steps, by one ULP. The arm64 JIT and
the NEON handwritten decoders fuse the multiply-add, and the steps only match
that when the compiler contracts a * b + c - which clang does and MSVC doesn't,
in Debug or Release. Spell out which one happens instead of relying on it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Henrik RydgårdandClaude Opus 5 committed 2026-09-21 12:13:09 -06:00
1 parent a1ed24ae2d
commit c58baedd75
3 files changed
+34 -10
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GPU/Common/VertexDecoderCommon.cpp
+22 -8
View File
@@ -352,32 +352,46 @@ void VertexDecoder::Step_TcFloatThrough(const VertexDecoder *dec, const u8 *ptr,
gstate_c.vertBounds.maxV = std::max(gstate_c.vertBounds.maxV, (u16)uvdata[1]);
}
// The arm64 JIT and the NEON handwritten decoders fuse the UV prescale (FMLA), the x86 ones don't
// (MULPS + ADDPS). Spell out which one happens here instead of leaving it to the compiler's
// contraction setting: clang contracts this by default and MSVC doesn't, so relying on it makes the
// steps disagree with the JIT on Windows on ARM only.
static inline float PrescaleUV(float value, float scale, float offset) {
#if PPSSPP_ARCH(ARM64_NEON)
return fmaf(value, scale, offset);
#else
// Safe as long as x86 stays on the SSE2 baseline, which has nothing to contract into. A build
// targeting FMA would need this spelled out too, the other way around from the arm64 one.
return value * scale + offset;
#endif
}
void VertexDecoder::Step_TcU8Prescale(const VertexDecoder *dec, const u8 *ptr, u8 *decoded) {
float *uv = (float *)(decoded + dec->decFmt.uvoff);
const u8 *uvdata = (const u8 *)(ptr + dec->tcoff);
uv[0] = (float)uvdata[0] * (1.f / 128.f) * dec->prescaleUV_->uScale + dec->prescaleUV_->uOff;
uv[1] = (float)uvdata[1] * (1.f / 128.f) * dec->prescaleUV_->vScale + dec->prescaleUV_->vOff;
uv[0] = PrescaleUV((float)uvdata[0] * (1.f / 128.f), dec->prescaleUV_->uScale, dec->prescaleUV_->uOff);
uv[1] = PrescaleUV((float)uvdata[1] * (1.f / 128.f), dec->prescaleUV_->vScale, dec->prescaleUV_->vOff);
}
void VertexDecoder::Step_TcU16Prescale(const VertexDecoder *dec, const u8 *ptr, u8 *decoded) {
float *uv = (float *)(decoded + dec->decFmt.uvoff);
const u16_le *uvdata = (const u16_le *)(ptr + dec->tcoff);
uv[0] = (float)uvdata[0] * (1.f / 32768.f) * dec->prescaleUV_->uScale + dec->prescaleUV_->uOff;
uv[1] = (float)uvdata[1] * (1.f / 32768.f) * dec->prescaleUV_->vScale + dec->prescaleUV_->vOff;
uv[0] = PrescaleUV((float)uvdata[0] * (1.f / 32768.f), dec->prescaleUV_->uScale, dec->prescaleUV_->uOff);
uv[1] = PrescaleUV((float)uvdata[1] * (1.f / 32768.f), dec->prescaleUV_->vScale, dec->prescaleUV_->vOff);
}
void VertexDecoder::Step_TcU16DoublePrescale(const VertexDecoder *dec, const u8 *ptr, u8 *decoded) {
float *uv = (float *)(decoded + dec->decFmt.uvoff);
const u16_le *uvdata = (const u16_le *)(ptr + dec->tcoff);
uv[0] = (float)uvdata[0] * (1.f / 16384.f) * dec->prescaleUV_->uScale + dec->prescaleUV_->uOff;
uv[1] = (float)uvdata[1] * (1.f / 16384.f) * dec->prescaleUV_->vScale + dec->prescaleUV_->vOff;
uv[0] = PrescaleUV((float)uvdata[0] * (1.f / 16384.f), dec->prescaleUV_->uScale, dec->prescaleUV_->uOff);
uv[1] = PrescaleUV((float)uvdata[1] * (1.f / 16384.f), dec->prescaleUV_->vScale, dec->prescaleUV_->vOff);
}
void VertexDecoder::Step_TcFloatPrescale(const VertexDecoder *dec, const u8 *ptr, u8 *decoded) {
float *uv = (float *)(decoded + dec->decFmt.uvoff);
const float_le *uvdata = (const float_le *)(ptr + dec->tcoff);
uv[0] = uvdata[0] * dec->prescaleUV_->uScale + dec->prescaleUV_->uOff;
uv[1] = uvdata[1] * dec->prescaleUV_->vScale + dec->prescaleUV_->vOff;
uv[0] = PrescaleUV(uvdata[0], dec->prescaleUV_->uScale, dec->prescaleUV_->uOff);
uv[1] = PrescaleUV(uvdata[1], dec->prescaleUV_->vScale, dec->prescaleUV_->vOff);
}
void VertexDecoder::Step_TcU8MorphToFloat(const VertexDecoder *dec, const u8 *ptr, u8 *decoded) {