projects / dragonfly.git / blame
| Commit | Line | Data |
|---|---|---|
| b34b60bc JS |
1 | /* |
| 2 | * Written by J.T. Conklin <jtc@NetBSD.org>. | |
| 3 | * Public domain. | |
| 4 | * | |
| 74dfd0cf | 5 | * $NetBSD: e_expf.S,v 1.6 2008/06/24 17:27:56 drochner Exp $ $ |
| b34b60bc JS |
6 | */ |
| 7 | ||
| 8 | #include <machine/asm.h> | |
| 9 | ||
| 10 | #include "abi.h" | |
| 11 | ||
| 12 | /* e^x = 2^(x * log2(e)) */ | |
| 13 | ENTRY(expf) | |
| 14 | XMM_ONE_ARG_FLOAT_PROLOGUE | |
| 74dfd0cf JM |
15 | |
| 16 | /* | |
| 17 | * catch +/-Inf and NaN arguments | |
| 18 | */ | |
| 19 | movl ARG_FLOAT_ONE,%eax | |
| 20 | andl $0x7fffffff,%eax | |
| 21 | cmpl $0x7f800000,%eax | |
| 22 | jae x_Inf_or_NaN | |
| 23 | ||
| b34b60bc JS |
24 | flds ARG_FLOAT_ONE |
| 25 | fldl2e | |
| 26 | fmulp /* x * log2(e) */ | |
| 27 | fld %st(0) | |
| 28 | frndint /* int(x * log2(e)) */ | |
| 29 | fsubr %st(0),%st(1) /* fract(x * log2(e)) */ | |
| 30 | fxch | |
| 31 | f2xm1 /* 2^(fract(x * log2(e))) - 1 */ | |
| 32 | fld1 | |
| 33 | faddp /* 2^(fract(x * log2(e))) */ | |
| 34 | fscale /* e^x */ | |
| 35 | fstp %st(1) | |
| 36 | XMM_FLOAT_EPILOGUE | |
| 37 | ret | |
| 74dfd0cf JM |
38 | |
| 39 | x_Inf_or_NaN: | |
| 40 | /* | |
| 41 | * Return 0 if x is -Inf. Otherwise just return x, although the | |
| 42 | * C version would return (x + x) (Real Indefinite) if x is a NaN. | |
| 43 | */ | |
| 44 | movl ARG_FLOAT_ONE,%eax | |
| 45 | cmpl $0xff800000,%eax | |
| 46 | jne x_not_minus_Inf | |
| 47 | fldz | |
| 48 | XMM_FLOAT_EPILOGUE | |
| 49 | ret | |
| 50 | ||
| 51 | x_not_minus_Inf: | |
| 52 | flds ARG_FLOAT_ONE | |
| 53 | XMM_FLOAT_EPILOGUE | |
| 54 | ret | |
| d04e8698 | 55 | END(expf) |
| 70e34eb2 JM |
56 | |
| 57 | .section .note.GNU-stack,"",%progbits |