math: fix x86 asin, atan, exp, log1p to raise underflow

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

diff --git a/src/math/i386/asin.s b/src/math/i386/asin.s
index 932c754..a9f691b 100644 (file)
--- a/src/math/i386/asin.s
+++ b/src/math/i386/asin.s
@@ -2,7 +2,18 @@
 .type asinf,@function
 asinf:
        flds 4(%esp)
-       jmp 1f
+       mov 4(%esp),%eax
+       add %eax,%eax
+       cmp $0x01000000,%eax
+       jae 1f
+               # subnormal x, return x with underflow
+       fnstsw %ax
+       and $16,%ax
+       jnz 2f
+       fld %st(0)
+       fmul %st(1)
+       fstps 4(%esp)
+2:     ret
 
 .global asinl
 .type asinl,@function
@@ -14,6 +25,16 @@ asinl:
 .type asin,@function
 asin:
        fldl 4(%esp)
+       mov 8(%esp),%eax
+       add %eax,%eax
+       cmp $0x00200000,%eax
+       jae 1f
+               # subnormal x, return x with underflow
+       fnstsw %ax
+       and $16,%ax
+       jnz 2f
+       fsts 4(%esp)
+2:     ret
 1:     fld %st(0)
        fld1
        fsub %st(0),%st(1)