From 673797718385500ee2aed3cee882a53ee2d2630b Mon Sep 17 00:00:00 2001
From: irisz64 <simococo03@gmail.com>
Date: Wed, 3 Sep 2025 12:11:38 +0200
Subject: [PATCH] Finally passing every FPU test in Lemmy's suite

---
 .../core/interpreter/cop1instructions.cpp     | 31 +++++++++----------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/backend/core/interpreter/cop1instructions.cpp b/src/backend/core/interpreter/cop1instructions.cpp
index 1f7dff88..3f0f891f 100644
--- a/src/backend/core/interpreter/cop1instructions.cpp
+++ b/src/backend/core/interpreter/cop1instructions.cpp
@@ -258,25 +258,23 @@ bool Cop1::CheckArgs(const T f1, const T f2) {
   return true;
 }
 
-template <bool preserveCause>
-bool Cop1::CheckFPUUsable() {
+template<>
+bool Cop1::CheckFPUUsable<true>() {
   Registers& regs = Core::GetRegs();
-  if constexpr (preserveCause) {
-    if (!regs.cop0.status.cu1) {
-      regs.cop0.FireException(ExceptionCode::CoprocessorUnusable, 1, regs.oldPC);
-      return false;
-    }
-  } else {
-    if (!CheckFPUUsable<true>())
-      return false;
-    fcr31.cause = {};
+  if (!regs.cop0.status.cu1) {
+    regs.cop0.FireException(ExceptionCode::CoprocessorUnusable, 1, regs.oldPC);
+    return false;
   }
 
   return true;
 }
 
-template bool Cop1::CheckFPUUsable<true>();
-template bool Cop1::CheckFPUUsable<false>();
+template<>
+bool Cop1::CheckFPUUsable<false>() {
+  if (!CheckFPUUsable<true>()) return false;
+  fcr31.cause = {};
+  return true;
+}
 
 template <typename T>
 FORCE_INLINE T FlushResult(T f, const u32 round) {
@@ -427,14 +425,14 @@ bool Cop1::SetCauseInvalid() {
 
 #define CHECK_FPE_IMPL(type, res, operation, convert)                                                                  \
   feclearexcept(FE_ALL_EXCEPT);                                                                                        \
-  volatile type v##res = [&]() -> type { return operation; }();                                                        \
+  volatile type v##res = [&]() __attribute__((noinline)) -> type { return operation; }();                                      \
   if (TestExceptions<convert>())                                                                                       \
     return;                                                                                                            \
   type res = v##res;
 
 #define CHECK_FPE_IMPL_CONST(type, res, operation, convert)                                                            \
   feclearexcept(FE_ALL_EXCEPT);                                                                                        \
-  volatile type v##res = [&]() -> type { return operation; }();                                                        \
+  volatile type v##res = [&]() __attribute__((noinline)) -> type { return operation; }();                                                        \
   if (TestExceptions<convert>())                                                                                       \
     return;                                                                                                            \
   const type res = v##res;
@@ -641,8 +639,7 @@ void Cop1::cvtsw(const Instruction instr) {
     return;
   const auto fs = FGR_S<s32>(regs.cop0.status, instr.fs());
   CHECK_FPE(float, fd, fs)
-  if (!CheckResult(fd))
-    return;
+  if (!CheckResult(fd)) return;
   FGR_D<float>(regs.cop0.status, instr.fd()) = fd;
 }