From 442d6450bb13ec6282395161075c54849bfc7fe7 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 24 Feb 2019 16:44:51 -0800
Subject: [PATCH] interp: Correct prefixes on vfad and vavg.

Including write mask, which didn't work before.
---
 Core/MIPS/MIPSIntVFPU.cpp | 60 ++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/Core/MIPS/MIPSIntVFPU.cpp b/Core/MIPS/MIPSIntVFPU.cpp
index b4fc2fea5c..9b782a45ad 100644
--- a/Core/MIPS/MIPSIntVFPU.cpp
+++ b/Core/MIPS/MIPSIntVFPU.cpp
@@ -1390,46 +1390,60 @@ namespace MIPSInt
 		EatPrefixes();
 	}
 	
-	void Int_Vfad(MIPSOpcode op)
-	{
-		float s[4];
+	void Int_Vfad(MIPSOpcode op) {
+		float s[4]{}, t[4]{};
 		float d;
 		int vd = _VD;
 		int vs = _VS;
 		VectorSize sz = GetVecSize(op);
 		ReadVector(s, sz, vs);
-		ApplySwizzleS(s, sz);
-		float sum = 0.0f;
-		int n = GetNumVectorElements(sz);
-		for (int i = 0; i < n; i++)
-		{
-			sum += s[i];
+		ApplySwizzleS(s, V_Quad);
+
+		// T prefix generates constants, but abs can change the constant.
+		u32 tprefixRemove = VFPU_ANY_SWIZZLE();
+		u32 tprefixAdd = VFPU_MAKE_CONSTANTS(VFPUConst::ONE, VFPUConst::ONE, VFPUConst::ONE, VFPUConst::ONE);
+		ApplyPrefixST(t, VFPURewritePrefix(VFPU_CTRL_TPREFIX, tprefixRemove, tprefixAdd), V_Quad);
+
+		d = 0.0f;
+		for (int i = 0; i < 4; i++) {
+			d += s[i] * t[i];
 		}
-		d = sum;
-		ApplyPrefixD(&d,V_Single);
-		V(vd) = d;
+		ApplyPrefixD(&d, V_Single);
+		WriteVector(&d, V_Single, vd);
 		PC += 4;
 		EatPrefixes();
 	}
 
-	void Int_Vavg(MIPSOpcode op)
-	{
-		float s[4];
+	void Int_Vavg(MIPSOpcode op) {
+		float s[4]{}, t[4]{};
 		float d;
 		int vd = _VD;
 		int vs = _VS;
 		VectorSize sz = GetVecSize(op);
 		ReadVector(s, sz, vs);
-		ApplySwizzleS(s, sz);
-		float sum = 0.0f;
-		int n = GetNumVectorElements(sz);
-		for (int i = 0; i < n; i++)
-		{
-			sum += s[i];
+		ApplySwizzleS(s, V_Quad);
+
+		// T prefix generates constants, but supports negate.
+		u32 tprefixRemove = VFPU_ANY_SWIZZLE() | VFPU_ABS(1, 1, 1, 1);
+		u32 tprefixAdd;
+		if (sz == V_Single)
+			tprefixAdd = VFPU_MAKE_CONSTANTS(VFPUConst::ZERO, VFPUConst::ZERO, VFPUConst::ZERO, VFPUConst::ZERO);
+		else if (sz == V_Pair)
+			tprefixAdd = VFPU_MAKE_CONSTANTS(VFPUConst::HALF, VFPUConst::HALF, VFPUConst::HALF, VFPUConst::HALF);
+		else if (sz == V_Triple)
+			tprefixAdd = VFPU_MAKE_CONSTANTS(VFPUConst::THIRD, VFPUConst::THIRD, VFPUConst::THIRD, VFPUConst::THIRD);
+		else if (sz == V_Quad)
+			tprefixAdd = VFPU_MAKE_CONSTANTS(VFPUConst::FOURTH, VFPUConst::FOURTH, VFPUConst::FOURTH, VFPUConst::FOURTH);
+		else
+			tprefixAdd = 0;
+		ApplyPrefixST(t, VFPURewritePrefix(VFPU_CTRL_TPREFIX, tprefixRemove, tprefixAdd), V_Quad);
+
+		d = 0.0f;
+		for (int i = 0; i < 4; i++) {
+			d += s[i] * t[i];
 		}
-		d = sum / n;
 		ApplyPrefixD(&d, V_Single);
-		V(vd) = d;
+		WriteVector(&d, V_Single, vd);
 		PC += 4;
 		EatPrefixes();
 	}