Let's see if we can do without the special checks in double precision.

hrydgard · Oct 10, 2020 · 512dbd3 · 512dbd3
1 parent e92bfcd
commit 512dbd3
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diff --git a/Core/MIPS/MIPSVFPUUtils.h b/Core/MIPS/MIPSVFPUUtils.h
@@ -29,16 +29,21 @@ inline int Xpose(int v) {
 	return v^0x20;
 }
 
+// Half of PI, or 90 degrees.
 #ifndef M_PI_2
 #define M_PI_2     1.57079632679489661923
 #endif
 
+// The VFPU uses weird angles where 4.0 represents a full circle. This makes it possible to return
+// exact 1.0/-1.0 values at certain angles.
+
 // Some games depend on exact values, but sinf() and cosf() aren't always precise.
 // Stepping down to [0, 2pi) helps, but we also check common exact-result values.
 // TODO: cos(1) and sin(2) should be -0.0, but doing that gives wrong results (possibly from floorf.)
 // Messing around with the modulo functions? try https://www.desmos.com/calculator.
 inline float vfpu_sin(float angle_f) {
 	double angle = angle_f;
+	/*
 	angle -= floor(angle * 0.25) * 4.;
 	if (angle == 0.0f || angle == 2.0) {
 		return 0.0f;
@@ -47,12 +52,14 @@ inline float vfpu_sin(float angle_f) {
 	} else if (angle == 3.0f) {
 		return -1.0f;
 	}
+	*/
 	angle *= M_PI_2;
 	return (float)sin(angle);
 }
 
 inline float vfpu_cos(float angle_f) {
 	double angle = angle_f;
+	/*
 	angle -= floor(angle * 0.25) * 4.;
 	if (angle == 1.0 || angle == 3.0) {
 		return 0.0f;
@@ -61,6 +68,7 @@ inline float vfpu_cos(float angle_f) {
 	} else if (angle == 2.0) {
 		return -1.0f;
 	}
+	*/
 	angle *= (float)M_PI_2;
 	return (float)cos(angle);
 }

diff --git a/unittest/UnitTest.cpp b/unittest/UnitTest.cpp
@@ -23,6 +23,9 @@
 //
 // TODO: Make a test of nice unittest asserts and count successes etc.
 // Or just integrate with an existing testing framework.
+//
+// To use, set command line parameter to one or more of the tests below, or "all".
+// Search for "availableTests".
 
 #include <cstdio>
 #include <cstdlib>
@@ -308,10 +311,19 @@ bool TestVFPUSinCos() {
 	EXPECT_APPROX_EQ_FLOAT(sine, 1.0f);
 	EXPECT_APPROX_EQ_FLOAT(cosine, 0.0f);
 
-	for (float angle = -10.0f; angle < 10.0f; angle++) {
+	vfpu_sincos(-1.0f, sine, cosine);
+	EXPECT_EQ_FLOAT(sine, -1.0f);
+	EXPECT_EQ_FLOAT(cosine, 0.0f);
+	vfpu_sincos(-2.0f, sine, cosine);
+	EXPECT_EQ_FLOAT(sine, 0.0f);
+	EXPECT_EQ_FLOAT(cosine, -1.0f);
+
+	for (float angle = -10.0f; angle < 10.0f; angle += 0.1f) {
 		vfpu_sincos(angle, sine, cosine);
 		EXPECT_APPROX_EQ_FLOAT(sine, sinf(angle * M_PI_2));
 		EXPECT_APPROX_EQ_FLOAT(cosine, cosf(angle * M_PI_2));
+
+		printf("sine: %f==%f cosine: %f==%f\n", sine, sinf(angle * M_PI_2), cosine, cosf(angle * M_PI_2));
 	}
 	return true;
 }