From 2da1bf7ffc564c7ff62e05e98ad8b5662a18318f Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 30 Oct 2022 21:47:28 -0700
Subject: [PATCH] interp: Correct dprefix accuracy for vrot.

Ignores cosine lane, not always x.
---
 Core/MIPS/MIPSIntVFPU.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Core/MIPS/MIPSIntVFPU.cpp b/Core/MIPS/MIPSIntVFPU.cpp
index bc1120921e..1b2c8d60ec 100644
--- a/Core/MIPS/MIPSIntVFPU.cpp
+++ b/Core/MIPS/MIPSIntVFPU.cpp
@@ -1629,8 +1629,9 @@ namespace MIPSInt
 			d[cosineLane] = cosine;
 		}
 
-		// D prefix works, just not for x.
-		currentMIPS->vfpuCtrl[VFPU_CTRL_DPREFIX] &= 0xFFEFC;
+		// D prefix works, just not for the cosine lane.
+		uint32_t dprefixRemove = (3 << cosineLane) | (1 << (8 + cosineLane));
+		currentMIPS->vfpuCtrl[VFPU_CTRL_DPREFIX] &= 0xFFFFF ^ dprefixRemove;
 		ApplyPrefixD(d, sz);
 		WriteVector(d, sz, vd);
 		PC += 4;