math: move x86_64 fabs, fabsf to C with inline asm

diff --git a/src/math/x86_64/fabs.c b/src/math/x86_64/fabs.c
new file mode 100644 (file)
index 0000000..1656247
--- /dev/null
+++ b/src/math/x86_64/fabs.c
@@ -0,0 +1,10 @@
+#include <math.h>
+
+double fabs(double x)
+{
+       double t;
+       __asm__ ("pcmpeqd %0, %0" : "=x"(t));          // t = ~0
+       __asm__ ("psrlq   $1, %0" : "+x"(t));          // t >>= 1
+       __asm__ ("andps   %1, %0" : "+x"(x) : "x"(t)); // x &= t
+       return x;
+}

diff --git a/src/math/x86_64/fabs.s b/src/math/x86_64/fabs.s
deleted file mode 100644 (file)
index 5715005..0000000
--- a/src/math/x86_64/fabs.s
+++ /dev/null
@@ -1,9 +0,0 @@
-.global fabs
-.type fabs,@function
-fabs:
-       xor %eax,%eax
-       dec %rax
-       shr %rax
-       movq %rax,%xmm1
-       andpd %xmm1,%xmm0
-       ret

diff --git a/src/math/x86_64/fabsf.c b/src/math/x86_64/fabsf.c
new file mode 100644 (file)
index 0000000..36ea748
--- /dev/null
+++ b/src/math/x86_64/fabsf.c
@@ -0,0 +1,10 @@
+#include <math.h>
+
+float fabsf(float x)
+{
+       float t;
+       __asm__ ("pcmpeqd %0, %0" : "=x"(t));          // t = ~0
+       __asm__ ("psrld   $1, %0" : "+x"(t));          // t >>= 1
+       __asm__ ("andps   %1, %0" : "+x"(x) : "x"(t)); // x &= t
+       return x;
+}

diff --git a/src/math/x86_64/fabsf.s b/src/math/x86_64/fabsf.s
deleted file mode 100644 (file)
index 501a1f1..0000000
--- a/src/math/x86_64/fabsf.s
+++ /dev/null
@@ -1,7 +0,0 @@
-.global fabsf
-.type fabsf,@function
-fabsf:
-       mov $0x7fffffff,%eax
-       movq %rax,%xmm1
-       andps %xmm1,%xmm0
-       ret