From 65750586b6c22c32736f2718281f7bc6f647ad42 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Thu, 21 Mar 2024 15:19:44 +0200
Subject: [PATCH] LibC: Use GCC builtins for math functions

---
 libc/CMakeLists.txt |  2 +-
 libc/math.S         | 26 -------------------
 libc/math.cpp       | 63 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 27 deletions(-)
 delete mode 100644 libc/math.S
 create mode 100644 libc/math.cpp

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 84a6e388..1eceb640 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -28,7 +28,7 @@ set(LIBC_SOURCES
 	termios.cpp
 	time.cpp
 	unistd.cpp
-	math.S
+	math.cpp
 	icxxabi.cpp
 
 	../BAN/BAN/Assert.cpp
diff --git a/libc/math.S b/libc/math.S
deleted file mode 100644
index 2e6f8fdc..00000000
--- a/libc/math.S
+++ /dev/null
@@ -1,26 +0,0 @@
-
-.global floorl;
-floorl:
-	fldt	8(%rsp)
-
-	fnstenv	-28(%rsp)		/* store fpu environment */
-
-	/* We use here %edx although only the low 1 bits are defined.
-	  But none of the operations should care and they are faster
-	  than the 16 bit operations.  */
-	movl	$0x400,%edx		/* round towards -oo */
-	orl	-28(%rsp),%edx
-	andl	$0xf7ff,%edx
-	movl	%edx,-32(%rsp)
-	fldcw	-32(%rsp)		/* load modified control word */
-
-	frndint				/* round */
-
-	/* Preserve "invalid" exceptions from sNaN input.  */
-	fnstsw
-	andl	$0x1, %eax
-	orl	%eax, -24(%rsp)
-
-	fldenv	-28(%rsp)		/* restore original environment */
-
-	ret
diff --git a/libc/math.cpp b/libc/math.cpp
new file mode 100644
index 00000000..53764dcf
--- /dev/null
+++ b/libc/math.cpp
@@ -0,0 +1,63 @@
+#include <math.h>
+
+#define BUILTINS1(func) \
+	float func##f(float a) { return __builtin_##func##f(a); } \
+	double func(double a) { return __builtin_##func(a); } \
+	long double func##l(long double a) { return __builtin_##func##l(a); }
+
+#define BUILTINS2(func) \
+	float func##f(float a, float b) { return __builtin_##func##f(a, b); } \
+	double func(double a, double b) { return __builtin_##func(a, b); } \
+	long double func##l(long double a, long double b) { return __builtin_##func##l(a, b); } \
+
+__BEGIN_DECLS
+
+BUILTINS1(acos)
+BUILTINS1(acosh)
+BUILTINS1(asin)
+BUILTINS1(asinh)
+BUILTINS1(atan)
+BUILTINS2(atan2)
+BUILTINS1(atanh)
+BUILTINS1(cbrt)
+BUILTINS1(ceil)
+BUILTINS2(copysign)
+BUILTINS1(cos)
+BUILTINS1(cosh)
+BUILTINS1(erf)
+BUILTINS1(erfc)
+BUILTINS1(exp)
+BUILTINS1(exp2)
+BUILTINS1(expm1)
+BUILTINS1(fabs)
+BUILTINS2(fdim)
+BUILTINS1(floor)
+BUILTINS2(fmax)
+BUILTINS2(fmin)
+BUILTINS2(fmod)
+BUILTINS2(hypot)
+BUILTINS1(j0)
+BUILTINS1(j1)
+BUILTINS1(lgamma)
+BUILTINS1(log)
+BUILTINS1(log10)
+BUILTINS1(log1p)
+BUILTINS1(log2)
+BUILTINS1(logb)
+BUILTINS1(nearbyint)
+BUILTINS2(nextafter)
+BUILTINS2(pow)
+BUILTINS2(remainder)
+BUILTINS1(rint)
+BUILTINS1(round)
+BUILTINS1(sin)
+BUILTINS1(sinh)
+BUILTINS1(sqrt)
+BUILTINS1(tan)
+BUILTINS1(tanh)
+BUILTINS1(tgamma)
+BUILTINS1(trunc)
+BUILTINS1(y0)
+BUILTINS1(y1)
+
+__END_DECLS