X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fmath%2Fi386%2Fexp.s;h=e3b42af5ae244fde2e2e30b048d9877d9d1a1177;hp=ca0de1d4f2ac5b7a5db23de24777fb75bd0c7002;hb=a8f73bb1a685dd7d67669c6f6ceb255cfa967790;hpb=0b0735af457e599a26a5f82f9e4615c60deac161

diff --git a/src/math/i386/exp.s b/src/math/i386/exp.s
index ca0de1d4..e3b42af5 100644
--- a/src/math/i386/exp.s
+++ b/src/math/i386/exp.s
@@ -50,12 +50,6 @@ expf:
 	flds 4(%esp)
 	jmp 2f
 
-.global expl
-.type expl,@function
-expl:
-	fldt 4(%esp)
-	jmp 2f
-
 .global exp
 .type exp,@function
 exp:
@@ -69,18 +63,18 @@ exp:
 exp2:
 	fldl 4(%esp)
 1:	pushl $0x467ff000
-	flds (%esp)
+	flds (%esp)       # 16380
 	xorl %eax,%eax
 	pushl $0x80000000
 	push %eax
 	fld %st(1)
 	fabs
-	fucom %st(1)
+	fucomp %st(1)
 	fnstsw
 	fstp %st(0)
-	fstp %st(0)
 	sahf
-	ja 2f
+	ja 3f             # |x| > 16380
+	jp 2f             # x is nan (avoid invalid except in fistp)
 	fld %st(0)
 	fistpl 8(%esp)
 	fildl 8(%esp)
@@ -90,30 +84,27 @@ 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:	fld %st(0)
+3:	fld %st(0)
 	fstpt (%esp)
-	mov 9(%esp),%ah
-	and $0x7f,%ah
-	cmp $0x7f,%ah
-	jne 1f
-	decb 9(%esp)
-	fstp %st(0)
-	fldt (%esp)
-1:	fld %st(0)
+	fld1
+	mov 8(%esp),%ax
+	and $0x7fff,%ax
+	cmp $0x7fff,%ax
+	je 1f             # x = +-inf
+	fld %st(1)
 	frndint
-	fxch %st(1)
-	fsub %st(1)
+	fxch %st(2)
+	fsub %st(2)       # st(0)=x-rint(x), st(1)=1, st(2)=rint(x)
 	f2xm1
-	fld1
-	faddp
-	fscale
+	faddp             # 2^(x-rint(x))
+1:	fscale
 	fstp %st(1)
 	add $12,%esp
 	ret