From 12256275156112ea7dc7c80bfbc73bc679326464 Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Sat, 1 Oct 2022 20:31:21 -0400
Subject: macro_jit_x64: fix miscompilation of bit extraction operations

---
 src/video_core/macro/macro_jit_x64.cpp | 46 +++++++---------------------------
 1 file changed, 9 insertions(+), 37 deletions(-)

diff --git a/src/video_core/macro/macro_jit_x64.cpp b/src/video_core/macro/macro_jit_x64.cpp
index aca25d902..3b55228b9 100644
--- a/src/video_core/macro/macro_jit_x64.cpp
+++ b/src/video_core/macro/macro_jit_x64.cpp
@@ -279,28 +279,13 @@ void MacroJITx64Impl::Compile_ExtractInsert(Macro::Opcode opcode) {
     auto dst = Compile_GetRegister(opcode.src_a, RESULT);
     auto src = Compile_GetRegister(opcode.src_b, eax);
 
-    if (opcode.bf_src_bit != 0 && opcode.bf_src_bit != 31) {
-        shr(src, opcode.bf_src_bit);
-    } else if (opcode.bf_src_bit == 31) {
-        xor_(src, src);
-    }
-    // Don't bother masking the whole register since we're using a 32 bit register
-    if (opcode.bf_size != 31 && opcode.bf_size != 0) {
-        and_(src, opcode.GetBitfieldMask());
-    } else if (opcode.bf_size == 0) {
-        xor_(src, src);
-    }
-    if (opcode.bf_dst_bit != 31 && opcode.bf_dst_bit != 0) {
-        shl(src, opcode.bf_dst_bit);
-    } else if (opcode.bf_dst_bit == 31) {
-        xor_(src, src);
-    }
-
     const u32 mask = ~(opcode.GetBitfieldMask() << opcode.bf_dst_bit);
-    if (mask != 0xffffffff) {
-        and_(dst, mask);
-    }
+    and_(dst, mask);
+    shr(src, opcode.bf_src_bit);
+    and_(src, opcode.GetBitfieldMask());
+    shl(src, opcode.bf_dst_bit);
     or_(dst, src);
+
     Compile_ProcessResult(opcode.result_operation, opcode.dst);
 }
 
@@ -309,17 +294,9 @@ void MacroJITx64Impl::Compile_ExtractShiftLeftImmediate(Macro::Opcode opcode) {
     const auto src = Compile_GetRegister(opcode.src_b, RESULT);
 
     shr(src, dst.cvt8());
-    if (opcode.bf_size != 0 && opcode.bf_size != 31) {
-        and_(src, opcode.GetBitfieldMask());
-    } else if (opcode.bf_size == 0) {
-        xor_(src, src);
-    }
+    and_(src, opcode.GetBitfieldMask());
+    shl(src, opcode.bf_dst_bit);
 
-    if (opcode.bf_dst_bit != 0 && opcode.bf_dst_bit != 31) {
-        shl(src, opcode.bf_dst_bit);
-    } else if (opcode.bf_dst_bit == 31) {
-        xor_(src, src);
-    }
     Compile_ProcessResult(opcode.result_operation, opcode.dst);
 }
 
@@ -327,13 +304,8 @@ void MacroJITx64Impl::Compile_ExtractShiftLeftRegister(Macro::Opcode opcode) {
     const auto dst = Compile_GetRegister(opcode.src_a, ecx);
     const auto src = Compile_GetRegister(opcode.src_b, RESULT);
 
-    if (opcode.bf_src_bit != 0) {
-        shr(src, opcode.bf_src_bit);
-    }
-
-    if (opcode.bf_size != 31) {
-        and_(src, opcode.GetBitfieldMask());
-    }
+    shr(src, opcode.bf_src_bit);
+    and_(src, opcode.GetBitfieldMask());
     shl(src, dst.cvt8());
 
     Compile_ProcessResult(opcode.result_operation, opcode.dst);
-- 
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