| /* | |
| * Written by J.T. Conklin <jtc@netbsd.org>. | |
| * Adapted for exp2 by Ulrich Drepper <drepper@cygnus.com>. | |
| * Public domain. | |
| */ | |
| .file "exp2f.S" | |
| .text | |
| .align 4 | |
| .globl _exp2f | |
| .def _exp2f; .scl 2; .type 32; .endef | |
| _exp2f: | |
| flds 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 | |
| frndint /* int(x) */ | |
| 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 |