1 | /* -------------------------------------------------------------- */ |
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2 | /* (C)Copyright 2001,2008, */ |
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3 | /* International Business Machines Corporation, */ |
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4 | /* Sony Computer Entertainment, Incorporated, */ |
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5 | /* Toshiba Corporation, */ |
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6 | /* */ |
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7 | /* All Rights Reserved. */ |
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8 | /* */ |
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9 | /* Redistribution and use in source and binary forms, with or */ |
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10 | /* without modification, are permitted provided that the */ |
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11 | /* following conditions are met: */ |
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12 | /* */ |
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13 | /* - Redistributions of source code must retain the above copyright*/ |
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14 | /* notice, this list of conditions and the following disclaimer. */ |
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15 | /* */ |
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16 | /* - Redistributions in binary form must reproduce the above */ |
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17 | /* copyright notice, this list of conditions and the following */ |
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18 | /* disclaimer in the documentation and/or other materials */ |
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19 | /* provided with the distribution. */ |
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20 | /* */ |
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21 | /* - Neither the name of IBM Corporation nor the names of its */ |
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22 | /* contributors may be used to endorse or promote products */ |
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23 | /* derived from this software without specific prior written */ |
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24 | /* permission. */ |
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25 | /* */ |
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26 | /* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */ |
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27 | /* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */ |
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28 | /* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */ |
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29 | /* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */ |
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30 | /* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */ |
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31 | /* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */ |
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32 | /* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */ |
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33 | /* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */ |
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34 | /* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */ |
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35 | /* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */ |
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36 | /* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */ |
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37 | /* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */ |
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38 | /* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ |
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39 | /* -------------------------------------------------------------- */ |
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40 | /* PROLOG END TAG zYx */ |
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41 | #ifdef __SPU__ |
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42 | #ifndef _POWF4_H_ |
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43 | #define _POWF4_H_ 1 |
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44 | |
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45 | #include <spu_intrinsics.h> |
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46 | #include <vec_types.h> |
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47 | |
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48 | #include "exp2f4.h" |
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49 | #include "log2f4.h" |
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50 | |
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51 | /* |
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52 | * FUNCTION |
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53 | * vector float _powf4(vector float x, vector float y) |
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54 | * |
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55 | * DESCRIPTION |
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56 | * The _powf4 function computes x raised to the power y for the set of |
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57 | * vectors. The powf4 function is computed as by decomposing |
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58 | * the problem into: |
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59 | * |
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60 | * x^y = 2^(y*log2(x)) |
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61 | * |
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62 | */ |
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63 | static __inline vector float _powf4(vector float x, vector float y) |
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64 | { |
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65 | vec_uint4 y_exp; |
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66 | vec_uint4 y_mantissa; |
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67 | vec_uint4 mant_shift; |
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68 | vec_uint4 y_is_int; |
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69 | vec_uint4 y_is_odd; |
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70 | vec_uint4 x_sign_bit; |
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71 | vec_uint4 zero = (vec_uint4)spu_splats(0); |
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72 | vec_uint4 bit0 = (vec_uint4)spu_splats(0x80000000); |
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73 | vec_int4 error = spu_splats(-1); |
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74 | vec_float4 out; |
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75 | |
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76 | y_exp = spu_and(spu_rlmask((vec_uint4)y, -23), 0x000000FF); |
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77 | |
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78 | /* Need the implied bit in the mantissa to catch |
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79 | * y = 1 case later |
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80 | */ |
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81 | y_mantissa = spu_or(spu_sl((vec_uint4)y, (unsigned int)8), bit0); |
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82 | |
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83 | x_sign_bit = spu_and((vec_uint4)x, bit0); |
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84 | |
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85 | /* We are going to shift the mantissa over enough to |
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86 | * determine if we have an integer. |
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87 | */ |
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88 | mant_shift = spu_add(y_exp, -127); |
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89 | |
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90 | |
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91 | /* Leave the lowest-order integer bit of mantissa on the |
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92 | * high end so we can see if the integer is odd. |
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93 | */ |
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94 | y_mantissa = spu_sl(y_mantissa, mant_shift); |
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95 | |
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96 | y_is_int = spu_cmpeq(spu_andc(y_mantissa, bit0), 0); |
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97 | y_is_int = spu_and(y_is_int, spu_cmpgt(y_exp, 126)); |
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98 | |
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99 | y_is_odd = spu_and(spu_cmpeq(y_mantissa, bit0), y_is_int); |
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100 | |
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101 | out = _exp2f4(spu_mul(y, _log2f4(spu_andc(x, (vec_float4)bit0)))); |
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102 | |
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103 | /* x < 0 is only ok when y integer |
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104 | */ |
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105 | out = spu_sel(out, (vec_float4)error, |
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106 | spu_andc(spu_cmpeq(x_sign_bit, bit0), y_is_int)); |
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107 | |
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108 | /* Preserve the sign of x if y is an odd integer |
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109 | */ |
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110 | out = spu_sel(out, spu_or(out, (vec_float4)x_sign_bit), y_is_odd); |
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111 | |
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112 | /* x = anything, y = +/- 0, returns 1 |
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113 | */ |
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114 | out = spu_sel(out, spu_splats(1.0f), spu_cmpabseq(y, (vec_float4)zero)); |
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115 | |
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116 | return(out); |
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117 | } |
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118 | |
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119 | #endif /* _POWF4_H_ */ |
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120 | #endif /* __SPU__ */ |
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