56 lines
1010 B
ArmAsm
56 lines
1010 B
ArmAsm
/*
|
|
* Written by J.T. Conklin <jtc@netbsd.org>.
|
|
* Public domain.
|
|
*/
|
|
|
|
#include <machine/asm.h>
|
|
|
|
#include "abi.h"
|
|
|
|
RCSID("$NetBSD: e_exp.S,v 1.11 2001/06/19 17:49:36 fvdl Exp $")
|
|
|
|
/* e^x = 2^(x * log2(e)) */
|
|
ENTRY(__ieee754_exp)
|
|
#ifdef __i386__
|
|
pushl %ebp
|
|
movl %esp,%ebp
|
|
subl $8,%esp
|
|
|
|
fstcw -12(%ebp) /* store fpu control word */
|
|
movw -12(%ebp),%dx
|
|
orw $0x0180,%dx
|
|
movw %dx,-16(%ebp)
|
|
fldcw -16(%ebp) /* load modfied control word */
|
|
fldl 8(%ebp)
|
|
#else
|
|
fstcw -12(%rsp)
|
|
movw -12(%rsp),%dx
|
|
orw $0x0180,%dx
|
|
movw %dx,-16(%rsp)
|
|
fldcw -16(%rsp)
|
|
movsd %xmm0,-8(%rsp)
|
|
fldl -8(%rsp)
|
|
#endif
|
|
|
|
fldl2e
|
|
fmulp /* x * log2(e) */
|
|
fld %st(0)
|
|
frndint /* int(x * log2(e)) */
|
|
fxch %st(1)
|
|
fsub %st(1),%st /* fract(x * log2(e)) */
|
|
f2xm1 /* 2^(fract(x * log2(e))) - 1 */
|
|
fld1
|
|
faddp /* 2^(fract(x * log2(e))) */
|
|
fscale /* e^x */
|
|
fstp %st(1)
|
|
|
|
#ifdef __i386__
|
|
fldcw -12(%ebp) /* restore original control word */
|
|
leave
|
|
#else
|
|
fstpl -8(%rsp)
|
|
movsd -8(%rsp),%xmm0
|
|
fldcw -12(%rsp)
|
|
#endif
|
|
ret
|