X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Fi386%2Fexp.s;h=c7f5ad0fc0cc3cdc458db86a0fd6d3219a778583;hp=76ab4d6465e298c408f64876ba8cb293a6e2d986;hb=1fb01691547e85be253a4f1543be3920de651e27;hpb=02db27d9deaee71b244c91e720ec819c74dab150

diff --git a/src/math/i386/exp.s b/src/math/i386/exp.s
index 76ab4d64..c7f5ad0f 100644
--- a/src/math/i386/exp.s
+++ b/src/math/i386/exp.s
@@ -68,21 +68,19 @@ exp:
 .type exp2,@function
 exp2:
 	fldl 4(%esp)
-1:	mov $0x47000000,%eax
-	push %eax
-	flds (%esp)
-	shl $7,%eax
-	push %eax
-	add %eax,%eax
+1:	pushl $0x467ff000
+	flds (%esp)       # 16380
+	xorl %eax,%eax
+	pushl $0x80000000
 	push %eax
 	fld %st(1)
 	fabs
-	fucom %st(1)
+	fucomp %st(1)
 	fnstsw
-	sahf
-	ja 2f
-	fstp %st(0)
 	fstp %st(0)
+	sahf
+	ja 3f             # |x| > 16380
+	jp 2f             # x is nan (avoid invalid except in fistp)
 	fld %st(0)
 	fistpl 8(%esp)
 	fildl 8(%esp)
@@ -92,29 +90,27 @@ exp2:
 	add %eax,8(%esp)
 	f2xm1
 	fld1
-	faddp
-	fldt (%esp)
+	faddp             # 2^(x-rint(x))
+	fldt (%esp)       # 2^rint(x)
 	fmulp
 	fstp %st(1)
-	add $12,%esp
+2:	add $12,%esp
 	ret
 
-2:	fstp %st(0)
-	fstp %st(0)
-	fsts 8(%esp)
-	mov 8(%esp),%eax
-	lea (%eax,%eax),%ecx
-	cmp $0xff000000,%ecx
-	ja 2f
-	fstp %st(0)
-	xor %ecx,%ecx
-	inc %ecx
-	add %eax,%eax
-	jc 1f
-	mov $0x7ffe,%ecx
-1:	mov %ecx,8(%esp)
-	fldt (%esp)
-	fld %st(0)
-	fmulp
-2:	add $12,%esp
+3:	fld %st(0)
+	fstpt (%esp)
+	fld1
+	mov 8(%esp),%ax
+	and $0x7fff,%ax
+	cmp $0x7fff,%ax
+	je 1f             # x = +-inf
+	fld %st(1)
+	frndint
+	fxch %st(2)
+	fsub %st(2)       # st(0)=x-rint(x), st(1)=1, st(2)=rint(x)
+	f2xm1
+	faddp             # 2^(x-rint(x))
+1:	fscale
+	fstp %st(1)
+	add $12,%esp
 	ret