1231855Sbz/*
2231855Sbz * Written by J.T. Conklin <jtc@NetBSD.org>.
3281974Sngie * Public domain.
4281974Sngie */
5231855Sbz
6276486Sngie#include <machine/asm.h>
7231855Sbz
8231855Sbz#include "abi.h"
9281974Sngie
10281974Sngie
11281974SngieRCSID("$NetBSD: e_expf.S,v 1.5 2003/07/26 19:24:58 salo Exp $")
12281974Sngie
13231855Sbz/* e^x = 2^(x * log2(e)) */
14231855SbzENTRY(__ieee754_expf)
15231855Sbz	XMM_ONE_ARG_FLOAT_PROLOGUE
16231855Sbz
17	/*
18	 * catch +/-Inf and NaN arguments
19	 */
20	movl	ARG_FLOAT_ONE,%eax
21	andl	$0x7fffffff,%eax
22	cmpl	$0x7f800000,%eax
23	jae	x_Inf_or_NaN
24
25	flds	ARG_FLOAT_ONE
26	fldl2e
27	fmulp				/* x * log2(e) */
28	fld	%st(0)
29	frndint				/* int(x * log2(e)) */
30	fsubr	%st(0),%st(1)		/* fract(x * log2(e)) */
31	fxch
32	f2xm1				/* 2^(fract(x * log2(e))) - 1 */
33	fld1
34	faddp				/* 2^(fract(x * log2(e))) */
35	fscale				/* e^x */
36	fstp	%st(1)
37	XMM_FLOAT_EPILOGUE
38	ret
39
40x_Inf_or_NaN:
41	/*
42	 * Return 0 if x is -Inf.  Otherwise just return x, although the
43	 * C version would return (x + x) (Real Indefinite) if x is a NaN.
44	 */
45	movl	ARG_FLOAT_ONE,%eax
46	cmpl	$0xff800000,%eax
47	jne	x_not_minus_Inf
48	fldz
49	XMM_FLOAT_EPILOGUE
50	ret
51
52x_not_minus_Inf:
53	flds	ARG_FLOAT_ONE
54	XMM_FLOAT_EPILOGUE
55	ret
56