From 8a3c96a413e57f9a2474b5241a1e1a5fa584d4ba Mon Sep 17 00:00:00 2001
From: Henrik Rydgard <hrydgard@gmail.com>
Date: Thu, 8 Oct 2015 11:03:08 +0200
Subject: [PATCH] ARM64: Don't need to avoid destroying SCRATCH1 in these
 functions.

---
 Core/MIPS/ARM64/Arm64CompFPU.cpp | 1 +
 Core/MIPS/ARM64/Arm64Jit.cpp     | 9 +++------
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/Core/MIPS/ARM64/Arm64CompFPU.cpp b/Core/MIPS/ARM64/Arm64CompFPU.cpp
index df71b3b3d4..d34f8333c1 100644
--- a/Core/MIPS/ARM64/Arm64CompFPU.cpp
+++ b/Core/MIPS/ARM64/Arm64CompFPU.cpp
@@ -386,6 +386,7 @@ void Arm64Jit::Comp_mxc1(MIPSOpcode op)
 			if (!wasImm) {
 				UBFX(gpr.R(MIPS_REG_FPCOND), gpr.R(rt), 23, 1);
 			}
+			// TODO: We do have the fcr31 value in a register here, could use that in UpdateRoundingMode to avoid reloading it.
 			UpdateRoundingMode();
 			ApplyRoundingMode();
 		} else {
diff --git a/Core/MIPS/ARM64/Arm64Jit.cpp b/Core/MIPS/ARM64/Arm64Jit.cpp
index 71dfa81e78..96b4b51807 100644
--- a/Core/MIPS/ARM64/Arm64Jit.cpp
+++ b/Core/MIPS/ARM64/Arm64Jit.cpp
@@ -524,6 +524,7 @@ void Arm64Jit::WriteDownCountR(ARM64Reg reg, bool updateFlags) {
 	}
 }
 
+// Destroys SCRATCH2
 void Arm64Jit::RestoreRoundingMode(bool force) {
 	// If the game has never set an interesting rounding mode, we can safely skip this.
 	if (force || js.hasSetRounding) {
@@ -537,8 +538,8 @@ void Arm64Jit::RestoreRoundingMode(bool force) {
 	}
 }
 
+// Destroys SCRATCH1 and SCRATCH2
 void Arm64Jit::ApplyRoundingMode(bool force) {
-	// NOTE: Must not destroy SCRATCH1.
 	// If the game has never set an interesting rounding mode, we can safely skip this.
 	if (force || js.hasSetRounding) {
 		LDR(INDEX_UNSIGNED, SCRATCH2, CTXREG, offsetof(MIPSState, fcr31));
@@ -551,7 +552,6 @@ void Arm64Jit::ApplyRoundingMode(bool force) {
 		CMPI2R(SCRATCH2, 4);
 		// At this point, if it was zero, we can skip the rest.
 		FixupBranch skip = B(CC_EQ);
-		PUSH(SCRATCH1);
 
 		// MIPS Rounding Mode:       ARM Rounding Mode
 		//   0: Round nearest        0
@@ -584,13 +584,12 @@ void Arm64Jit::ApplyRoundingMode(bool force) {
 		MOVP2R(SCRATCH1_64, &js.currentRoundingFunc);
 		STR(INDEX_UNSIGNED, SCRATCH2_64, SCRATCH1_64, 0);
 
-		POP(SCRATCH1);
 		SetJumpTarget(skip);
 	}
 }
 
+// Destroys SCRATCH1 and SCRATCH2
 void Arm64Jit::UpdateRoundingMode() {
-	// NOTE: Must not destroy SCRATCH1.
 	LDR(INDEX_UNSIGNED, SCRATCH2, CTXREG, offsetof(MIPSState, fcr31));
 
 	TSTI2R(SCRATCH2, 1 << 24);
@@ -603,11 +602,9 @@ void Arm64Jit::UpdateRoundingMode() {
 	CMPI2R(SCRATCH2, 3);
 
 	FixupBranch skip2 = B(CC_EQ);
-	PUSH(SCRATCH1_64);
 	MOVI2R(SCRATCH2, 1);
 	MOVP2R(SCRATCH1_64, &js.hasSetRounding);
 	STRB(INDEX_UNSIGNED, SCRATCH2, SCRATCH1_64, 0);
-	POP(SCRATCH1_64);
 	SetJumpTarget(skip2);
 }