From 8f9fe8690ad2d7747243b8f9cac9564582fcfe36 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Sat, 9 Mar 2019 00:08:08 -0500
Subject: [PATCH] common/fp/unpacked: Adjust FPUnpack to operate like ARM
 pseudocode

This function is defined as always disabling the AHP bit in the fpcr
before performing any operations.

At the same time, rename the original FPUnpack function to FPUnpackBase
to match the pseudocode in the ARM reference manual.
---
 src/common/fp/unpacked.cpp | 6 +++---
 src/common/fp/unpacked.h   | 8 +++++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/common/fp/unpacked.cpp b/src/common/fp/unpacked.cpp
index b30f47fe..45d2b584 100644
--- a/src/common/fp/unpacked.cpp
+++ b/src/common/fp/unpacked.cpp
@@ -15,7 +15,7 @@
 namespace Dynarmic::FP {
 
 template<typename FPT>
-std::tuple<FPType, bool, FPUnpacked> FPUnpack(FPT op, FPCR fpcr, FPSR& fpsr) {
+std::tuple<FPType, bool, FPUnpacked> FPUnpackBase(FPT op, FPCR fpcr, FPSR& fpsr) {
     constexpr size_t sign_bit = FPInfo<FPT>::exponent_width + FPInfo<FPT>::explicit_mantissa_width;
     constexpr size_t exponent_high_bit = FPInfo<FPT>::exponent_width + FPInfo<FPT>::explicit_mantissa_width - 1;
     constexpr size_t exponent_low_bit = FPInfo<FPT>::explicit_mantissa_width;
@@ -52,8 +52,8 @@ std::tuple<FPType, bool, FPUnpacked> FPUnpack(FPT op, FPCR fpcr, FPSR& fpsr) {
     return {FPType::Nonzero, sign, {sign, exp, frac}};
 }
 
-template std::tuple<FPType, bool, FPUnpacked> FPUnpack<u32>(u32 op, FPCR fpcr, FPSR& fpsr);
-template std::tuple<FPType, bool, FPUnpacked> FPUnpack<u64>(u64 op, FPCR fpcr, FPSR& fpsr);
+template std::tuple<FPType, bool, FPUnpacked> FPUnpackBase<u32>(u32 op, FPCR fpcr, FPSR& fpsr);
+template std::tuple<FPType, bool, FPUnpacked> FPUnpackBase<u64>(u64 op, FPCR fpcr, FPSR& fpsr);
 
 template<size_t F>
 std::tuple<bool, int, u64, ResidualError> Normalize(FPUnpacked op, int extra_right_shift = 0) {
diff --git a/src/common/fp/unpacked.h b/src/common/fp/unpacked.h
index ae206c19..13e43474 100644
--- a/src/common/fp/unpacked.h
+++ b/src/common/fp/unpacked.h
@@ -52,7 +52,13 @@ constexpr FPUnpacked ToNormalized(bool sign, int exponent, u64 value) {
 }
 
 template<typename FPT>
-std::tuple<FPType, bool, FPUnpacked> FPUnpack(FPT op, FPCR fpcr, FPSR& fpsr);
+std::tuple<FPType, bool, FPUnpacked> FPUnpackBase(FPT op, FPCR fpcr, FPSR& fpsr);
+
+template<typename FPT>
+std::tuple<FPType, bool, FPUnpacked> FPUnpack(FPT op, FPCR fpcr, FPSR& fpsr) {
+    fpcr.AHP(false);
+    return FPUnpackBase(op, fpcr, fpsr);
+}
 
 template<typename FPT>
 std::tuple<FPType, bool, FPUnpacked> FPUnpackCV(FPT op, FPCR fpcr, FPSR& fpsr) {