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1 "{ Package: 'stx:libbasic2' }" |
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2 |
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3 "{ NameSpace: Smalltalk }" |
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4 |
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5 LimitedPrecisionReal variableByteSubclass:#QuadFloat |
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6 instanceVariableNames:'' |
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7 classVariableNames:'QuadFloatZero QuadFloatOne Pi E Epsilon NaN PositiveInfinity |
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8 NegativeInfinity Halfpi HalfpiNegative' |
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9 poolDictionaries:'' |
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10 category:'Magnitude-Numbers' |
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11 ! |
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12 |
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13 !QuadFloat class methodsFor:'documentation'! |
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14 |
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15 documentation |
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16 " |
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17 QuadFloats represent rational numbers with limited precision |
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18 and are mapped to IEEE quadruple precision format (128bit). |
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19 If the underlying cpu supports them natively, the machine format (long double) is |
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20 used. Otherwise, a software emulation is done, which is much slower. |
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21 Thus only use them, if you really need the additional precision; |
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22 if not, use Float (which are doubles) or LongFloats which usually have IEEE extended precision (80bit). |
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23 |
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24 QuadFloats give you definite 128 bit quadruple floats, |
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25 thus, code using quadFloats is guaranteed to be portable from one architecture to another. |
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26 |
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27 Representation: |
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28 gcc-sparc: |
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29 128bit quadruple IEEE floats (16bytes); |
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30 112 bit mantissa, |
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31 16 bit exponent, |
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32 34 decimal digits (approx.) |
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33 |
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34 Mixed mode arithmetic: |
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35 quadFloat op anyFloat -> longFloat |
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36 longFloat op complex -> complex |
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37 |
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38 Range and precision of storage formats: see LimitedPrecisionReal >> documentation |
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39 |
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40 [author:] |
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41 Claus Gittinger |
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42 |
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43 [see also:] |
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44 Number |
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45 Float ShortFloat LongFloat Fraction FixedPoint Integer Complex |
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46 FloatArray DoubleArray |
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47 https://en.wikipedia.org/wiki/Extended_precision |
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48 " |
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49 ! ! |
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50 |
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51 !QuadFloat class methodsFor:'instance creation'! |
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52 |
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53 basicNew |
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54 "return a new quadFloat - here we return 0.0 |
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55 - QuadFloats are usually NOT created this way ... |
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56 Its implemented here to allow things like binary store & load |
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57 of quadFloats. |
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58 (but it is not a good idea to store the bits of a float - the reader might have a |
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59 totally different representation - so floats should be |
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60 binary stored in a device independent format)." |
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61 |
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62 %{ /* NOCONTEXT */ |
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63 #ifndef __SCHTEAM__ |
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64 OBJ newFloat; |
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65 if (sizeof(long double) == sizeof(quadfloat)) { |
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66 __qMKLFLOAT(newFloat, 0.0); /* OBJECT ALLOCATION */ |
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67 } else { |
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68 __qMKQFLOAT(newFloat, 0.0); /* OBJECT ALLOCATION */ |
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69 } |
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70 RETURN (newFloat); |
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71 #endif /* not SCHTEAM */ |
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72 %} |
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73 |
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74 "Created: / 06-06-2019 / 17:18:58 / Claus Gittinger" |
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75 ! |
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76 |
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77 fromFloat:aFloat |
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78 "return a new quadFloat, given a float value" |
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79 |
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80 %{ /* NOCONTEXT */ |
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81 #ifndef __SCHTEAM__ |
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82 OBJ newFloat; |
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83 float128 f; |
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84 |
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85 if (__isFloatLike(aFloat)) { |
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86 float f = __floatVal(aFloat); |
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87 float128 qf = (LONGFLOAT)f; |
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88 __qMKQFLOAT(newFloat, lf); /* OBJECT ALLOCATION */ |
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89 RETURN (newFloat); |
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90 } |
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91 #endif |
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92 %}. |
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93 self error:'invalid argument' |
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94 |
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95 " |
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96 QuadFloat fromFloat:123.0 |
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97 123.0 asQuadFloat |
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98 123 asQuadFloat |
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99 " |
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100 |
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101 "Created: / 06-06-2019 / 18:01:03 / Claus Gittinger" |
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102 ! ! |
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103 |
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104 !QuadFloat class methodsFor:'coercing & converting'! |
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105 |
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106 coerce:aNumber |
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107 "convert the argument aNumber into an instance of the receiver's class and return it." |
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108 |
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109 ^ aNumber asQuadFloat. |
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110 |
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111 "Created: / 06-06-2019 / 16:51:01 / Claus Gittinger" |
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112 ! ! |
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113 |
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114 !QuadFloat class methodsFor:'constants'! |
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115 |
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116 NaN |
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117 "return a shortFloat which represents not-a-Number (i.e. an invalid number)" |
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118 |
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119 NaN isNil ifTrue:[ |
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120 NaN := super NaN |
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121 ]. |
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122 ^ NaN |
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123 |
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124 " |
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125 self NaN |
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126 " |
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127 |
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128 "Created: / 06-06-2019 / 16:56:09 / Claus Gittinger" |
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129 ! |
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130 |
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131 e |
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132 "return the constant e as quadFloat" |
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133 |
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134 E isNil ifTrue:[ |
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135 "/ eDigits has enough digits for 128bit IEEE quads |
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136 "/ do not use as a literal constant here - we cannot depend on the underlying C-compiler here... |
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137 E := self readFrom:(Number eDigits) |
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138 ]. |
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139 ^ E |
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140 |
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141 "Created: / 06-06-2019 / 17:01:54 / Claus Gittinger" |
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142 ! |
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143 |
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144 pi |
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145 "return the constant pi as quadFloat" |
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146 |
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147 Pi isNil ifTrue:[ |
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148 "/ piDigits has enough digits for 128bit IEEE quads |
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149 "/ do not use as a literal constant here - we cannot depend on the underlying C-compiler here... |
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150 Pi := self readFrom:(Number piDigits) |
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151 ]. |
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152 ^ Pi |
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153 |
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154 "Created: / 06-06-2019 / 17:09:51 / Claus Gittinger" |
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155 ! ! |
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156 |
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157 !QuadFloat class methodsFor:'documentation'! |
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158 |
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159 version_CVS |
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160 ^ '$Header$' |
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161 ! ! |
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162 |