From 557a01a787005c35e1cae40f5063ca95e21185c2 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Fri, 24 May 2019 18:55:31 -0400
Subject: [PATCH] common/fp/op: Add soft-float implementation of FPCompareEQ

This will be used to implement the half-precision floating-point
variants of FCMEQ in following changes.
---
 src/CMakeLists.txt             |  2 ++
 src/common/fp/op.h             |  1 +
 src/common/fp/op/FPCompare.cpp | 41 ++++++++++++++++++++++++++++++++++
 src/common/fp/op/FPCompare.h   | 17 ++++++++++++++
 4 files changed, 61 insertions(+)
 create mode 100644 src/common/fp/op/FPCompare.cpp
 create mode 100644 src/common/fp/op/FPCompare.h

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5e7cc5a7..0e3827ad 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -24,6 +24,8 @@ add_library(dynarmic
     common/fp/info.h
     common/fp/mantissa_util.h
     common/fp/op.h
+    common/fp/op/FPCompare.cpp
+    common/fp/op/FPCompare.h
     common/fp/op/FPConvert.cpp
     common/fp/op/FPConvert.h
     common/fp/op/FPMulAdd.cpp
diff --git a/src/common/fp/op.h b/src/common/fp/op.h
index b8ee1441..b1bd0ee0 100644
--- a/src/common/fp/op.h
+++ b/src/common/fp/op.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include "common/fp/op/FPCompare.h"
 #include "common/fp/op/FPConvert.h"
 #include "common/fp/op/FPMulAdd.h"
 #include "common/fp/op/FPRecipEstimate.h"
diff --git a/src/common/fp/op/FPCompare.cpp b/src/common/fp/op/FPCompare.cpp
new file mode 100644
index 00000000..7e16dd60
--- /dev/null
+++ b/src/common/fp/op/FPCompare.cpp
@@ -0,0 +1,41 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2019 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#include "common/fp/fpcr.h"
+#include "common/fp/fpsr.h"
+#include "common/fp/op/FPCompare.h"
+#include "common/fp/process_exception.h"
+#include "common/fp/unpacked.h"
+
+namespace Dynarmic::FP {
+
+template <typename FPT>
+bool FPCompareEQ(FPT lhs, FPT rhs, FPCR fpcr, FPSR& fpsr) {
+    const auto unpacked1 = FPUnpack(lhs, fpcr, fpsr);
+    const auto unpacked2 = FPUnpack(rhs, fpcr, fpsr);
+    const auto type1 = std::get<FPType>(unpacked1);
+    const auto type2 = std::get<FPType>(unpacked2);
+    const auto& value1 = std::get<FPUnpacked>(unpacked1);
+    const auto& value2 = std::get<FPUnpacked>(unpacked2);
+
+    if (type1 == FPType::QNaN || type1 == FPType::SNaN ||
+        type2 == FPType::QNaN || type2 == FPType::SNaN) {
+        if (type1 == FPType::SNaN || type2 == FPType::SNaN) {
+            FPProcessException(FPExc::InvalidOp, fpcr, fpsr);
+        }
+
+        // Comparisons against NaN are never equal.
+        return false;
+    }
+
+    return value1 == value2 || (type1 == FPType::Zero && type2 == FPType::Zero);
+}
+
+template bool FPCompareEQ<u16>(u16 lhs, u16 rhs, FPCR fpcr, FPSR& fpsr);
+template bool FPCompareEQ<u32>(u32 lhs, u32 rhs, FPCR fpcr, FPSR& fpsr);
+template bool FPCompareEQ<u64>(u64 lhs, u64 rhs, FPCR fpcr, FPSR& fpsr);
+
+} // namespace Dynarmic::FP
diff --git a/src/common/fp/op/FPCompare.h b/src/common/fp/op/FPCompare.h
new file mode 100644
index 00000000..33802848
--- /dev/null
+++ b/src/common/fp/op/FPCompare.h
@@ -0,0 +1,17 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2019 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#pragma once
+
+namespace Dynarmic::FP {
+
+class FPCR;
+class FPSR;
+
+template <typename FPT>
+bool FPCompareEQ(FPT lhs, FPT rhs, FPCR fpcr, FPSR& fpsr);
+
+} // namespace Dynarmic::FP