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Diffstat (limited to 'newlib/libm/machine/spu/headers/ldexp.h')
-rw-r--r-- | newlib/libm/machine/spu/headers/ldexp.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/ldexp.h b/newlib/libm/machine/spu/headers/ldexp.h new file mode 100644 index 000000000..811059c1d --- /dev/null +++ b/newlib/libm/machine/spu/headers/ldexp.h @@ -0,0 +1,83 @@ +/* + (C) Copyright 2001,2006, + International Business Machines Corporation, + Sony Computer Entertainment, Incorporated, + Toshiba Corporation, + + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright notice, + this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + * Neither the names of the copyright holders nor the names of their + contributors may be used to endorse or promote products derived from this + software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER + OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ +#ifndef _LDEXP_H_ +#define _LDEXP_H_ 1 + +#include <spu_intrinsics.h> +#include "headers/vec_literal.h" + +/* ldexp computes x * 2^exp. This function variant computes the result + * and handles overflow, underflow, and denorms by breaking the problem + * into: + * exp = MAX(exp, -2044) + * exp = MIN(exp, 2046) + * e1 = exp / 2 + * e2 = exp - e1; + * x * 2^e1 * 2^e2 + */ +static __inline double _ldexp(double x, int exp) +{ + vec_int4 e, e1, e2; + vec_int4 min = VEC_SPLAT_S32(-2044); + vec_int4 max = VEC_SPLAT_S32(2046); + vec_uint4 cmp_min, cmp_max; + vec_uint4 shift = VEC_LITERAL(vec_uint4, 20, 32, 20, 32); + vec_double2 f1, f2; + vec_double2 in, out; + + in = spu_promote(x, 0); + e = spu_promote(exp, 0); + + /* Clamp the specified exponent to the range -2044 to 2046. + */ + cmp_min = spu_cmpgt(e, min); + cmp_max = spu_cmpgt(e, max); + e = spu_sel(min, e, cmp_min); + e = spu_sel(e, max, cmp_max); + + /* Generate the factors f1 = 2^e1 and f2 = 2^e2 + */ + e1 = spu_rlmaska(e, -1); + e2 = spu_sub(e, e1); + + f1 = (vec_double2)spu_sl(spu_add(e1, 1023), shift); + f2 = (vec_double2)spu_sl(spu_add(e2, 1023), shift); + + /* Compute the product x * 2^e1 * 2^e2 + */ + out = spu_mul(spu_mul(in, f1), f2); + + return (spu_extract(out, 0)); +} + +#endif /* _LDEXP_H_ */ |