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124 lines
4.1 KiB
C
124 lines
4.1 KiB
C
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/*
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(C) Copyright 2001,2006,
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International Business Machines Corporation,
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Sony Computer Entertainment, Incorporated,
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Toshiba Corporation,
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the names of the copyright holders nor the names of their
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contributors may be used to endorse or promote products derived from this
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software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _FLOORF_H_
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#define _FLOORF_H_ 1
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#include <spu_intrinsics.h>
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#include "headers/vec_literal.h"
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/*
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* FUNCTION
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* float _floorf(float value)
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*
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* DESCRIPTION
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* The _floorf routine round the input value "value" downwards to the
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* nearest integer returning the result as a float. Two forms of the
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* floor function are provided - full range and limited (integer)
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* range.
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*
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* The full range form (default) provides floor computation on
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* all IEEE floating point values. The floor of NANs remain NANs.
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* The floor of denorms results in zero.
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*
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* The limited range form (selected by defining FLOOR_INTEGER_RANGE)
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* compute ths floor of all floating-point values in the 32-bit
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* signed integer range. Values outside this range get clamped.
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*/
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static __inline float _floorf(float value)
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{
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#ifdef FLOOR_INTEGER_RANGE
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/* 32-BIT INTEGER DYNAMIC RANGE
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*/
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union {
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float f;
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signed int i;
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unsigned int ui;
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} bias;
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bias.f = value;
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/* If positive, bias the input value to truncate towards
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* positive infinity, instead of zero.
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*/
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bias.ui = (unsigned int)(bias.i >> 31) & 0x3F7FFFFF;
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value -= bias.f;
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/* Remove fraction bits by casting to an integer and back
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* to a floating-point value.
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*/
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return ((float)((int)value));
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#else /* !FLOOR_INTEGER_RANGE */
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/* FULL FLOATING-POINT RANGE
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*/
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vec_int4 exp, shift;
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vec_uint4 mask, frac_mask, addend, insert, pos;
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vec_float4 in, out;
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in = spu_promote(value, 0);
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/* This function generates the following component
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* based upon the inputs.
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*
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* mask = bits of the input that need to be replaced.
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* insert = value of the bits that need to be replaced
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* addend = value to be added to perform function.
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*
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* These are applied as follows:.
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*
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* out = ((in & mask) | insert) + addend
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*/
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pos = spu_cmpgt((vec_int4)in, -1);
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exp = spu_and(spu_rlmask((vec_int4)in, -23), 0xFF);
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shift = spu_sub(127, exp);
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frac_mask = spu_and(spu_rlmask(VEC_SPLAT_U32(0x7FFFFF), shift),
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spu_cmpgt((vec_int4)shift, -31));
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mask = spu_orc(frac_mask, spu_cmpgt(exp, 126));
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addend = spu_andc(spu_andc(spu_add(mask, 1), pos),
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spu_cmpeq(spu_and((vec_uint4)in, mask), 0));
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insert = spu_andc(spu_andc(VEC_SPLAT_U32(0xBF800000), pos),
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spu_cmpgt((vec_uint4)spu_add(exp, -1), 126));
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out = (vec_float4)spu_add(spu_sel((vec_uint4)in, insert, mask), addend);
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return (spu_extract(out, 0));
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#endif /* FLOOR_INTEGER_RANGE */
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}
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#endif /* _FLOORF_H_ */
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