diff options
Diffstat (limited to 'newlib/libc/machine/i386/f_expf.c')
-rw-r--r-- | newlib/libc/machine/i386/f_expf.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/newlib/libc/machine/i386/f_expf.c b/newlib/libc/machine/i386/f_expf.c new file mode 100644 index 00000000000..43877276459 --- /dev/null +++ b/newlib/libc/machine/i386/f_expf.c @@ -0,0 +1,45 @@ +/* + * ==================================================== + * Copyright (C) 1998 by Cygnus Solutions. All rights reserved. + * + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +/* +Fast version of exp using Intel float instructions. + + float _f_expf (float x); + +Function computes e ** x. The following special cases exist: + 1. if x is 0.0 ==> return 1.0 + 2. if x is infinity ==> return infinity + 3. if x is -infinity ==> return 0.0 + 4. if x is NaN ==> return x +There is no error checking or setting of errno. +*/ + + +#include <math.h> +#include <ieeefp.h> +#include "f_math.h" + +float _f_expf (float x) +{ + if (check_finitef(x)) + { + float result; + asm ("fldl2e; fmulp; fld %%st; frndint; fsub %%st,%%st(1); fxch;" \ + "fchs; f2xm1; fld1; faddp; fxch; fld1; fscale; fstp %%st(1); fmulp" : + "=t"(result) : "0"(x)); + return result; + } + else if (x == -infinityf()) + return 0.0; + + return x; +} + + |