From: Alexander Monakov <amonakov@ispras.ru>
Date: Wed, 15 Jan 2020 15:42:46 +0000 (+0300)
Subject: math: move x87-family fmod functions to C with inline asm
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=bc87299ce72a52f4debf9fc19d859abe34dbdf43;p=oweals%2Fmusl.git

math: move x87-family fmod functions to C with inline asm
---

diff --git a/src/math/i386/fmod.c b/src/math/i386/fmod.c
new file mode 100644
index 00000000..ea0c58d9
--- /dev/null
+++ b/src/math/i386/fmod.c
@@ -0,0 +1,10 @@
+#include <math.h>
+
+double fmod(double x, double y)
+{
+	unsigned short fpsr;
+	// fprem does not introduce excess precision into x
+	do __asm__ ("fprem; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+	while (fpsr & 0x400);
+	return x;
+}
diff --git a/src/math/i386/fmod.s b/src/math/i386/fmod.s
deleted file mode 100644
index 2113b3c5..00000000
--- a/src/math/i386/fmod.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global fmod
-.type fmod,@function
-fmod:
-	fldl 12(%esp)
-	fldl 4(%esp)
-1:	fprem
-	fnstsw %ax
-	sahf
-	jp 1b
-	fstp %st(1)
-	ret
diff --git a/src/math/i386/fmodf.c b/src/math/i386/fmodf.c
new file mode 100644
index 00000000..90b56ab0
--- /dev/null
+++ b/src/math/i386/fmodf.c
@@ -0,0 +1,10 @@
+#include <math.h>
+
+float fmodf(float x, float y)
+{
+	unsigned short fpsr;
+	// fprem does not introduce excess precision into x
+	do __asm__ ("fprem; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+	while (fpsr & 0x400);
+	return x;
+}
diff --git a/src/math/i386/fmodf.s b/src/math/i386/fmodf.s
deleted file mode 100644
index e04e2a56..00000000
--- a/src/math/i386/fmodf.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global fmodf
-.type fmodf,@function
-fmodf:
-	flds 8(%esp)
-	flds 4(%esp)
-1:	fprem
-	fnstsw %ax
-	sahf
-	jp 1b
-	fstp %st(1)
-	ret
diff --git a/src/math/i386/fmodl.c b/src/math/i386/fmodl.c
new file mode 100644
index 00000000..3daeab06
--- /dev/null
+++ b/src/math/i386/fmodl.c
@@ -0,0 +1,9 @@
+#include <math.h>
+
+long double fmodl(long double x, long double y)
+{
+	unsigned short fpsr;
+	do __asm__ ("fprem; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+	while (fpsr & 0x400);
+	return x;
+}
diff --git a/src/math/i386/fmodl.s b/src/math/i386/fmodl.s
deleted file mode 100644
index 0cb3fe9b..00000000
--- a/src/math/i386/fmodl.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global fmodl
-.type fmodl,@function
-fmodl:
-	fldt 16(%esp)
-	fldt 4(%esp)
-1:	fprem
-	fnstsw %ax
-	sahf
-	jp 1b
-	fstp %st(1)
-	ret
diff --git a/src/math/x86_64/fmodl.c b/src/math/x86_64/fmodl.c
new file mode 100644
index 00000000..3daeab06
--- /dev/null
+++ b/src/math/x86_64/fmodl.c
@@ -0,0 +1,9 @@
+#include <math.h>
+
+long double fmodl(long double x, long double y)
+{
+	unsigned short fpsr;
+	do __asm__ ("fprem; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+	while (fpsr & 0x400);
+	return x;
+}
diff --git a/src/math/x86_64/fmodl.s b/src/math/x86_64/fmodl.s
deleted file mode 100644
index ea07b402..00000000
--- a/src/math/x86_64/fmodl.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global fmodl
-.type fmodl,@function
-fmodl:
-	fldt 24(%rsp)
-	fldt 8(%rsp)
-1:	fprem
-	fnstsw %ax
-	testb $4,%ah
-	jnz 1b
-	fstp %st(1)
-	ret