From edd795e9918c2903e148605adde53dca4f2d81a6 Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Sun, 22 Jul 2018 15:05:53 +0100
Subject: [PATCH] a64_emit_x64: Fix stack misalignment on Windows for 128-bit
 exclusive writes

Discovered by @Subv.
Includes a test to ensure this codepath is exercised on Windows.
---
 src/backend_x64/a64_emit_x64.cpp |  4 ++--
 tests/A64/a64.cpp                | 39 ++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/backend_x64/a64_emit_x64.cpp b/src/backend_x64/a64_emit_x64.cpp
index ae88f850..188cf0f0 100644
--- a/src/backend_x64/a64_emit_x64.cpp
+++ b/src/backend_x64/a64_emit_x64.cpp
@@ -896,7 +896,7 @@ void A64EmitX64::EmitExclusiveWrite(A64EmitContext& ctx, IR::Inst* inst, size_t
             ));
             break;
         case 128:
-            code.sub(rsp, 8 + 16 + ABI_SHADOW_SPACE);
+            code.sub(rsp, 16 + ABI_SHADOW_SPACE);
             code.lea(code.ABI_PARAM3, ptr[rsp + ABI_SHADOW_SPACE]);
             code.movaps(xword[code.ABI_PARAM3], xmm0);
             code.CallFunction(static_cast<u32(*)(A64::UserConfig&, u64, A64::Vector&)>(
@@ -906,7 +906,7 @@ void A64EmitX64::EmitExclusiveWrite(A64EmitContext& ctx, IR::Inst* inst, size_t
                     }) ? 0 : 1;
                 }
             ));
-            code.add(rsp, 8 + 16 + ABI_SHADOW_SPACE);
+            code.add(rsp, 16 + ABI_SHADOW_SPACE);
             break;
         default:
             UNREACHABLE();
diff --git a/tests/A64/a64.cpp b/tests/A64/a64.cpp
index ccceed8e..9f71eb95 100644
--- a/tests/A64/a64.cpp
+++ b/tests/A64/a64.cpp
@@ -6,6 +6,8 @@
 
 #include <catch.hpp>
 
+#include <dynarmic/A64/exclusive_monitor.h>
+
 #include "testenv.h"
 
 TEST_CASE("A64: ADD", "[a64]") {
@@ -274,3 +276,40 @@ TEST_CASE("A64: FABD", "[a64]") {
 
     REQUIRE(jit.GetVector(22) == Vector{0x56d3f0857fc90e2b, 0x6e4b0a4144873176});
 }
+
+TEST_CASE("A64: 128-bit exclusive read/write", "[a64]") {
+    TestEnv env;
+    Dynarmic::A64::ExclusiveMonitor monitor{1};
+
+    Dynarmic::A64::UserConfig conf;
+    conf.callbacks = &env;
+    conf.processor_id = 0;
+
+    SECTION("Local Monitor Only") {
+        conf.global_monitor = nullptr;
+    }
+    SECTION("Global Monitor") {
+        conf.global_monitor = &monitor;
+    }
+
+    Dynarmic::A64::Jit jit{conf};
+
+    env.code_mem[0] = 0xc87f0861; // LDXP X1, X2, [X3]
+    env.code_mem[1] = 0xc8241865; // STXP W4, X5, X6, [X3]
+    env.code_mem[2] = 0x14000000; // B .
+
+    jit.SetPC(0);
+    jit.SetRegister(3, 0x1234567812345678);
+    jit.SetRegister(4, 0xbaadbaadbaadbaad);
+    jit.SetRegister(5, 0xaf00d1e5badcafe0);
+    jit.SetRegister(6, 0xd0d0cacad0d0caca);
+
+    env.ticks_left = 3;
+    jit.Run();
+
+    REQUIRE(jit.GetRegister(1) == 0x7f7e7d7c7b7a7978);
+    REQUIRE(jit.GetRegister(2) == 0x8786858483828180);
+    REQUIRE(jit.GetRegister(4) == 0);
+    REQUIRE(env.MemoryRead64(0x1234567812345678) == 0xaf00d1e5badcafe0);
+    REQUIRE(env.MemoryRead64(0x1234567812345680) == 0xd0d0cacad0d0caca);
+}