newlib-cygwin/newlib/libm/machine/spu/headers/logbf4.h

99 lines
4.4 KiB
C

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/* (C)Copyright 2006,2008, */
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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _LOGBF4_H_
#define _LOGBF4_H_ 1
#include <spu_intrinsics.h>
#include <vec_types.h>
/*
* FUNCTION
* vector float _logbf4(vector float x)
*
* DESCRIPTION
* The _logbf4 function returns a vector float that contains the exponent
* of the corresponding elements of the input vector x. The exponent is
* defined by:
* x = frac * FLT_RADIX^exp, with frac in [1, FLT_RADIX).
*
* Special Cases:
* x = 0, result is undefined.
* x = NaN, result is NaN.
* x = infinity, +infinity is returned.
*
*/
static __inline vector float _logbf4(vector float x)
{
vec_uint4 lzero = (vector unsigned int) {0, 0, 0, 0};
vec_uint4 exp_mask = (vector unsigned int) {0xFF, 0xFF, 0xFF, 0xFF};
vec_int4 exp_shift = (vector signed int) { -23, -23, -23, -23};
vec_int4 exp_bias = (vector signed int) {-127, -127, -127, -127};
vec_uint4 sign_mask = (vector unsigned int) {0x80000000, 0x80000000,
0x80000000, 0x80000000};
vec_uint4 linf = (vector unsigned int) {0x7F800000, 0x7F800000,
0x7F800000, 0x7F800000};
vec_uint4 lminf = (vector unsigned int) {0xFF800000, 0xFF800000,
0xFF800000, 0xFF800000};
vec_uint4 exp;
vec_uint4 xabs;
vec_float4 exp_unbias;
xabs = spu_andc((vec_uint4)x, sign_mask);
exp = spu_and(spu_rlmask((vec_uint4)x, exp_shift), exp_mask);
exp_unbias = spu_convtf(spu_add((vec_int4)exp, exp_bias), 0);
/* Zero */
exp_unbias = spu_sel(exp_unbias, (vec_float4)lminf, (vec_uint4)spu_cmpeq(xabs, lzero));
/* NaN */
exp_unbias = spu_sel(exp_unbias, x, (vec_uint4)spu_cmpgt(xabs, linf));
/* Infinite */
exp_unbias = spu_sel(exp_unbias, (vec_float4)linf, (vec_uint4)spu_cmpeq(xabs, linf));
return (exp_unbias);
}
#endif /* _LOGBF4_H_ */
#endif /* __SPU__ */