From d52d383c224aa60d0d4541276e80e114486eaab3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Mon, 10 Oct 2022 10:46:51 +0200
Subject: [PATCH] Delete some misguided FPU control code, that we definitely
 don't want

---
 Common/Math/math_util.cpp | 43 ++-------------------------------------
 Common/Math/math_util.h   |  9 --------
 Qt/QtMain.cpp             |  1 -
 SDL/SDLMain.cpp           |  1 -
 ios/ViewController.mm     |  3 ---
 5 files changed, 2 insertions(+), 55 deletions(-)

diff --git a/Common/Math/math_util.cpp b/Common/Math/math_util.cpp
index 9b1a59a755..6e72791f87 100644
--- a/Common/Math/math_util.cpp
+++ b/Common/Math/math_util.cpp
@@ -1,44 +1,5 @@
 #include "Common/Math/math_util.h"
-#include <stdlib.h>
 
-// QNX can only use RunFast mode and it is already the default.
-#if defined(__ARM_ARCH_7A__)
-// Enables 'RunFast' VFP mode.
-void EnableFZ() {
-	int x;
-	asm(
-		"fmrx %[result],FPSCR \r\n"
-		"orr %[result],%[result],#16777216 \r\n"
-		"fmxr FPSCR,%[result]"
-		:[result] "=r" (x) : :
-	);
-	//printf("ARM FPSCR: %08x\n",x);
-}
+#include <cstdlib>
 
-// New fastmode code from: http://pandorawiki.org/Floating_Point_Optimization
-// These settings turbocharge the slow VFP unit on Cortex-A8 based chips by setting
-// restrictions that permit running VFP instructions on the NEON unit.
-// Denormal flush-to-zero, for example.
-void FPU_SetFastMode() {
-	static const unsigned int x = 0x04086060;
-	static const unsigned int y = 0x03000000;
-	int r;
-	asm volatile (
-		"fmrx	%0, fpscr			\n\t"	//r0 = FPSCR
-		"and	%0, %0, %1			\n\t"	//r0 = r0 & 0x04086060
-		"orr	%0, %0, %2			\n\t"	//r0 = r0 | 0x03000000
-		"fmxr	fpscr, %0			\n\t"	//FPSCR = r0
-		: "=r"(r)
-		: "r"(x), "r"(y)
-		);
-}
-
-#else
-
-void EnableFZ() {
-	// TODO
-}
-
-void FPU_SetFastMode() {}
-
-#endif
+// Could delete this file, but might find use again.
diff --git a/Common/Math/math_util.h b/Common/Math/math_util.h
index fd47662b54..8f8962cab4 100644
--- a/Common/Math/math_util.h
+++ b/Common/Math/math_util.h
@@ -189,12 +189,3 @@ inline uint16_t ShrinkToHalf(float full) {
 	FP16 fp = float_to_half_fast3(fp32);
 	return fp.u;
 }
-
-// FPU control.
-void EnableFZ();
-
-// Enable both FZ and Default-NaN. Is documented to flip some ARM implementation into a "run-fast" mode
-// where they can schedule VFP instructions on the NEON unit (these implementations have
-// very slow VFP units).
-// http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0274h/Babffifj.html
-void FPU_SetFastMode();
diff --git a/Qt/QtMain.cpp b/Qt/QtMain.cpp
index bba1f1ae2b..c6381a112d 100644
--- a/Qt/QtMain.cpp
+++ b/Qt/QtMain.cpp
@@ -316,7 +316,6 @@ static int mainInternal(QApplication &a) {
 	emugl->resize(pixel_xres, pixel_yres);
 	emugl->showFullScreen();
 #endif
-	EnableFZ();
 	// Disable screensaver
 #if defined(QT_HAS_SYSTEMINFO)
 	QScreenSaver ssObject(emugl);
diff --git a/SDL/SDLMain.cpp b/SDL/SDLMain.cpp
index da966cabae..0a6daa5361 100644
--- a/SDL/SDLMain.cpp
+++ b/SDL/SDLMain.cpp
@@ -807,7 +807,6 @@ int main(int argc, char *argv[]) {
 	} else {
 		joystick = nullptr;
 	}
-	EnableFZ();
 
 	int framecount = 0;
 	bool mouseDown = false;
diff --git a/ios/ViewController.mm b/ios/ViewController.mm
index c90c30a22a..63d241cf46 100644
--- a/ios/ViewController.mm
+++ b/ios/ViewController.mm
@@ -807,6 +807,3 @@ void bindDefaultFBO()
 {
 	[sharedViewController bindDefaultFBO];
 }
-
-void EnableFZ(){};
-void DisableFZ(){};