math: rewrite modf.c and clean up modff.c

[musl] / src / math / i386 / modff.s

diff --git a/src/math/i386/modff.s b/src/math/i386/modff.s
index d29b4b6..35a08ca 100644 (file)
--- a/src/math/i386/modff.s
+++ b/src/math/i386/modff.s
@@ -1,15 +1,28 @@
 .global modff
 .type modff,@function
 modff:
-       mov 8(%esp),%eax
+       mov 8(%esp),%ecx
        flds 4(%esp)
-       fld1
-       fld %st(1)
-1:     fprem
-       fstsw %ax
+       fxam
+       fnstsw %ax
        sahf
-       jp 1b
-       fstp %st(1)
-       fsubr %st(1)
-       fstps (%eax)
+        jnp 1f
+        jc 2f
+1:      fld1
+        fld %st(1)
+1:      fprem
+        fnstsw %ax
+        sahf
+        jp 1b
+        fstp %st(1)
+        fsubr %st(0),%st(1)
+        fxch %st(1)
+        fstps (%ecx)
+        ret
+
+2:     fstps (%ecx)
+       mov (%ecx),%eax
+       and $0x80000000,%eax
+       mov %eax,4(%esp)
+       flds 4(%esp)
        ret