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GTE: Use shift for IRGB/ORGB conversion

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Dividing rounds towards zero, which needs a fixup for negative values.
Those are clamped to zero regardless, so an arithmetic shift is the same.
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Stenzek
2026-10-10 21:47:43 +10:00
parent 7547f640c5
commit 50225103a1
1 changed files with 4 additions and 3 deletions
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src/core/gte.cpp
+4 -3
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@@ -334,9 +334,10 @@ u32 GTE::ReadRegister(u32 index)
case 29: // ORGB
{
// ORGB register, convert 16-bit to 555
const u8 r = static_cast<u8>(std::clamp(REGS.IR1 / 0x80, 0x00, 0x1F));
const u8 g = static_cast<u8>(std::clamp(REGS.IR2 / 0x80, 0x00, 0x1F));
const u8 b = static_cast<u8>(std::clamp(REGS.IR3 / 0x80, 0x00, 0x1F));
// Shifting rounds negative values down instead of towards zero, but they get clamped to zero either way.
const u8 r = static_cast<u8>(std::clamp(REGS.IR1 >> 7, 0x00, 0x1F));
const u8 g = static_cast<u8>(std::clamp(REGS.IR2 >> 7, 0x00, 0x1F));
const u8 b = static_cast<u8>(std::clamp(REGS.IR3 >> 7, 0x00, 0x1F));
return ZeroExtend32(r) | (ZeroExtend32(g) << 5) | (ZeroExtend32(b) << 10);
}