From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 19 Mar 2012 03:17:28 +0000 (-0400)
Subject: fix broken exponential asm
X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=commitdiff_plain;h=aa1b4dff45788f8205e32ea01da243fe09568aa8

fix broken exponential asm

infinities were getting converted into nans. the new code simply tests
for infinity and replaces it with a large magnitude value of the same
sign.

also, the fcomi instruction is apparently not part of the i387
instruction set, so avoid using it.
---

diff --git a/src/math/i386/exp.s b/src/math/i386/exp.s
index 18f6cd67..f4769d59 100644
--- a/src/math/i386/exp.s
+++ b/src/math/i386/exp.s
@@ -34,6 +34,15 @@ exp:
 .type exp2,@function
 exp2:
 	fldl 4(%esp)
+1:	fxam
+	fnstsw %ax
+	sahf
+	jnp 1f
+	jnc 1f
+	fstps 4(%esp)
+	mov $0xfe,%al
+	and %al,7(%esp)
+	flds 4(%esp)
 1:	fld %st(0)
 	frndint
 	fxch %st(1)
diff --git a/src/math/i386/expm1.s b/src/math/i386/expm1.s
index d6d511ef..bbb5d12e 100644
--- a/src/math/i386/expm1.s
+++ b/src/math/i386/expm1.s
@@ -14,12 +14,23 @@ expm1l:
 .type expm1,@function
 expm1:
 	fldl 4(%esp)
+1:	fxam
+	fnstsw %ax
+	sahf
+	jnp 1f
+	jnc 1f
+	fstps 4(%esp)
+	mov $0xfe,%al
+	and %al,7(%esp)
+	flds 4(%esp)
 1:	fldl2e
 	fmulp
 	fld %st(0)
 	frndint
 	fldz
-	fcompi
+	fcomp
+	fnstsw %ax
+	sahf
 	jnz 1f
 	fstp %st(0)
 	f2xm1