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

diff --git a/src/math/i386/remainder.c b/src/math/i386/remainder.c
new file mode 100644 (file)
index 0000000..c083df9
--- /dev/null
+++ b/src/math/i386/remainder.c
@@ -0,0 +1,12 @@
+#include <math.h>
+
+double remainder(double x, double y)
+{
+       unsigned short fpsr;
+       // fprem1 does not introduce excess precision into x
+       do __asm__ ("fprem1; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+       while (fpsr & 0x400);
+       return x;
+}
+
+weak_alias(remainder, drem);

diff --git a/src/math/i386/remainder.s b/src/math/i386/remainder.s
deleted file mode 100644 (file)
index ab1da95..0000000
--- a/src/math/i386/remainder.s
+++ /dev/null
@@ -1,14 +0,0 @@
-.global remainder
-.type remainder,@function
-remainder:
-.weak drem
-.type drem,@function
-drem:
-       fldl 12(%esp)
-       fldl 4(%esp)
-1:     fprem1
-       fnstsw %ax
-       sahf
-       jp 1b
-       fstp %st(1)
-       ret

diff --git a/src/math/i386/remainderf.c b/src/math/i386/remainderf.c
new file mode 100644 (file)
index 0000000..280207d
--- /dev/null
+++ b/src/math/i386/remainderf.c
@@ -0,0 +1,12 @@
+#include <math.h>
+
+float remainderf(float x, float y)
+{
+       unsigned short fpsr;
+       // fprem1 does not introduce excess precision into x
+       do __asm__ ("fprem1; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+       while (fpsr & 0x400);
+       return x;
+}
+
+weak_alias(remainderf, dremf);

diff --git a/src/math/i386/remainderf.s b/src/math/i386/remainderf.s
deleted file mode 100644 (file)
index 6a7378a..0000000
--- a/src/math/i386/remainderf.s
+++ /dev/null
@@ -1,14 +0,0 @@
-.global remainderf
-.type remainderf,@function
-remainderf:
-.weak dremf
-.type dremf,@function
-dremf:
-       flds 8(%esp)
-       flds 4(%esp)
-1:     fprem1
-       fnstsw %ax
-       sahf
-       jp 1b
-       fstp %st(1)
-       ret

diff --git a/src/math/i386/remainderl.c b/src/math/i386/remainderl.c
new file mode 100644 (file)
index 0000000..8cf7507
--- /dev/null
+++ b/src/math/i386/remainderl.c
@@ -0,0 +1,9 @@
+#include <math.h>
+
+long double remainderl(long double x, long double y)
+{
+       unsigned short fpsr;
+       do __asm__ ("fprem1; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+       while (fpsr & 0x400);
+       return x;
+}

diff --git a/src/math/i386/remainderl.s b/src/math/i386/remainderl.s
deleted file mode 100644 (file)
index b41518e..0000000
--- a/src/math/i386/remainderl.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global remainderl
-.type remainderl,@function
-remainderl:
-       fldt 16(%esp)
-       fldt 4(%esp)
-1:     fprem1
-       fnstsw %ax
-       sahf
-       jp 1b
-       fstp %st(1)
-       ret

diff --git a/src/math/x86_64/remainderl.c b/src/math/x86_64/remainderl.c
new file mode 100644 (file)
index 0000000..8cf7507
--- /dev/null
+++ b/src/math/x86_64/remainderl.c
@@ -0,0 +1,9 @@
+#include <math.h>
+
+long double remainderl(long double x, long double y)
+{
+       unsigned short fpsr;
+       do __asm__ ("fprem1; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
+       while (fpsr & 0x400);
+       return x;
+}

diff --git a/src/math/x86_64/remainderl.s b/src/math/x86_64/remainderl.s
deleted file mode 100644 (file)
index cb3857b..0000000
--- a/src/math/x86_64/remainderl.s
+++ /dev/null
@@ -1,11 +0,0 @@
-.global remainderl
-.type remainderl,@function
-remainderl:
-       fldt 24(%rsp)
-       fldt 8(%rsp)
-1:     fprem1
-       fnstsw %ax
-       testb $4,%ah
-       jnz 1b
-       fstp %st(1)
-       ret