newlib-cygwin/winsup/cygwin/math/exp2.S

95 lines
1.9 KiB
ArmAsm

/**
* This file has no copyright assigned and is placed in the Public Domain.
* This file is part of the mingw-w64 runtime package.
* No warranty is given; refer to the file DISCLAIMER.PD within this package.
*/
#include <_mingw_mac.h>
.file "exp2.S"
.text
#ifdef __x86_64__
.align 8
#else
.align 4
#endif
.globl __MINGW_USYMBOL(exp2)
.def __MINGW_USYMBOL(exp2); .scl 2; .type 32; .endef
__MINGW_USYMBOL(exp2):
#ifdef __x86_64__
subq $24, %rsp
movsd %xmm0,(%rsp)
fldl (%rsp)
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
fld %st
subq $8, %rsp /* int(x) */
fnstcw 4(%rsp)
movzwl 4(%rsp), %eax
orb $12, %ah
movw %ax, (%rsp)
fldcw (%rsp)
frndint
fldcw 4(%rsp)
addq $8, %rsp
fsubr %st,%st(1) /* fract(x) */
fxch
f2xm1 /* 2^(fract(x)) - 1 */
fld1
faddp /* 2^(fract(x)) */
fscale /* e^x */
fstp %st(1)
fstpl (%rsp)
movsd (%rsp),%xmm0
addq $24, %rsp
ret
1: testl $0x200, %eax /* Test sign. */
jz 2f /* If positive, jump. */
fstp %st
fldz /* Set result to 0. */
2: fstpl (%rsp)
movsd (%rsp),%xmm0
addq $24,%rsp
ret
#else
fldl 4(%esp)
/* I added the following ugly construct because exp(+-Inf) resulted
in NaN. The ugliness results from the bright minds at Intel.
For the i686 the code can be written better.
-- drepper@cygnus.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
fld %st
subl $8, %esp /* int(x) */
fnstcw 4(%esp)
movzwl 4(%esp), %eax
orb $12, %ah
movw %ax, (%esp)
fldcw (%esp)
frndint
fldcw 4(%esp)
addl $8, %esp
fsubr %st,%st(1) /* fract(x) */
fxch
f2xm1 /* 2^(fract(x)) - 1 */
fld1
faddp /* 2^(fract(x)) */
fscale /* e^x */
fstp %st(1)
ret
1: testl $0x200, %eax /* Test sign. */
jz 2f /* If positive, jump. */
fstp %st
fldz /* Set result to 0. */
2: ret
#endif