From 1d5c90d3707406a5712b07e7075f75e277b13e0a Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Mon, 5 Sep 2022 19:37:58 -0700
Subject: [PATCH] Ge: Read matrix num/data back like hardware.

In case any game accidentally relies on this.
---
 Core/HLE/sceGe.cpp | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/Core/HLE/sceGe.cpp b/Core/HLE/sceGe.cpp
index 46230373d28e..81667a448e8e 100644
--- a/Core/HLE/sceGe.cpp
+++ b/Core/HLE/sceGe.cpp
@@ -565,8 +565,32 @@ static int sceGeGetMtx(int type, u32 matrixPtr) {
 
 static u32 sceGeGetCmd(int cmd) {
 	if (cmd >= 0 && cmd < (int)ARRAY_SIZE(gstate.cmdmem)) {
-		// Does not mask away the high bits.
-		return hleLogSuccessInfoX(SCEGE, gstate.cmdmem[cmd]);
+		// Does not mask away the high bits.  But matrix regs don't read back.
+		u32 val = gstate.cmdmem[cmd];
+		switch (cmd) {
+		case GE_CMD_BONEMATRIXDATA:
+		case GE_CMD_WORLDMATRIXDATA:
+		case GE_CMD_VIEWMATRIXDATA:
+		case GE_CMD_PROJMATRIXDATA:
+		case GE_CMD_TGENMATRIXDATA:
+			val &= 0xFF000000;
+			break;
+
+		case GE_CMD_BONEMATRIXNUMBER:
+			val &= 0xFF00007F;
+			break;
+
+		case GE_CMD_WORLDMATRIXNUMBER:
+		case GE_CMD_VIEWMATRIXNUMBER:
+		case GE_CMD_PROJMATRIXNUMBER:
+		case GE_CMD_TGENMATRIXNUMBER:
+			val &= 0xFF00000F;
+			break;
+
+		default:
+			break;
+		}
+		return hleLogSuccessInfoX(SCEGE, val);
 	}
 	return hleLogError(SCEGE, SCE_KERNEL_ERROR_INVALID_INDEX);
 }