From e104a28b7137c167fc6a32f00b171db47c08531b Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 24 Sep 2023 23:03:25 -0700
Subject: [PATCH] irjit: Handle VDet.

---
 Core/MIPS/IR/IRCompVFPU.cpp | 15 ++++++++++++++-
 Core/MIPS/MIPSIntVFPU.cpp   |  2 +-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/Core/MIPS/IR/IRCompVFPU.cpp b/Core/MIPS/IR/IRCompVFPU.cpp
index e42ac78d25..b6f42b237f 100644
--- a/Core/MIPS/IR/IRCompVFPU.cpp
+++ b/Core/MIPS/IR/IRCompVFPU.cpp
@@ -1771,7 +1771,20 @@ namespace MIPSComp {
 		// d[0] = s[0]*t[1] - s[1]*t[0]
 		// Note: this operates on two vectors, not a 2x2 matrix.
 
-		DISABLE;
+		VectorSize sz = GetVecSize(op);
+		if (sz != V_Pair)
+			DISABLE;
+
+		u8 sregs[4], dregs[4], tregs[4];
+		GetVectorRegsPrefixS(sregs, sz, _VS);
+		GetVectorRegsPrefixT(tregs, sz, _VT);
+		GetVectorRegsPrefixD(dregs, V_Single, _VD);
+
+		ir.Write(IROp::FMul, IRVTEMP_0, sregs[1], tregs[0]);
+		ir.Write(IROp::FMul, dregs[0], sregs[0], tregs[1]);
+		ir.Write(IROp::FSub, dregs[0], dregs[0], IRVTEMP_0);
+
+		ApplyPrefixD(dregs, V_Single, _VD);
 	}
 
 	void IRFrontend::Comp_Vi2x(MIPSOpcode op) {
diff --git a/Core/MIPS/MIPSIntVFPU.cpp b/Core/MIPS/MIPSIntVFPU.cpp
index 35d3caa56a..9fcc409419 100644
--- a/Core/MIPS/MIPSIntVFPU.cpp
+++ b/Core/MIPS/MIPSIntVFPU.cpp
@@ -1446,7 +1446,7 @@ namespace MIPSInt
 			d[0] += s[2] * t[2] + s[3] * t[3];
 		}
 
-		ApplyPrefixD(d, sz);
+		ApplyPrefixD(d, V_Single);
 		WriteVector(d, V_Single, vd);
 		PC += 4;
 		EatPrefixes();