From: Szabolcs Nagy <nsz@port70.net>
Date: Thu, 15 Aug 2013 14:18:32 +0000 (+0000)
Subject: math: fix i386 atan2.s to raise underflow for subnormal results
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=411efb3bc61298b81456d0fdab39518d983a9681;p=musl

math: fix i386 atan2.s to raise underflow for subnormal results
---

diff --git a/src/math/i386/atan2.s b/src/math/i386/atan2.s
index 5c795aff..a7d2979b 100644
--- a/src/math/i386/atan2.s
+++ b/src/math/i386/atan2.s
@@ -4,4 +4,14 @@ atan2:
 	fldl 4(%esp)
 	fldl 12(%esp)
 	fpatan
-	ret
+	fstl 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 1f
+	fsts 4(%esp)
+1:	ret
diff --git a/src/math/i386/atan2f.s b/src/math/i386/atan2f.s
index 08627e63..14b88ce5 100644
--- a/src/math/i386/atan2f.s
+++ b/src/math/i386/atan2f.s
@@ -4,4 +4,16 @@ atan2f:
 	flds 4(%esp)
 	flds 8(%esp)
 	fpatan
-	ret
+	fsts 4(%esp)
+	mov 4(%esp),%eax
+	add %eax,%eax
+	cmp $0x01000000,%eax
+	jae 1f
+		# subnormal x, return x with underflow
+	fnstsw %ax
+	and $16,%ax
+	jnz 1f
+	fld %st(0)
+	fmul %st(1)
+	fstps 4(%esp)
+1:	ret