1 | /* This is a stripped down version of floatlib.c. It supplies only those |
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2 | functions which exist in libgcc, but for which there is not assembly |
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3 | language versions in m68k/lb1sf68.asm. |
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4 | |
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5 | It also includes simplistic support for extended floats (by working in |
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6 | double precision). You must compile this file again with -DEXTFLOAT |
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7 | to get this support. */ |
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8 | |
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9 | /* |
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10 | ** gnulib support for software floating point. |
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11 | ** Copyright (C) 1991 by Pipeline Associates, Inc. All rights reserved. |
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12 | ** Permission is granted to do *anything* you want with this file, |
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13 | ** commercial or otherwise, provided this message remains intact. So there! |
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14 | ** I would appreciate receiving any updates/patches/changes that anyone |
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15 | ** makes, and am willing to be the repository for said changes (am I |
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16 | ** making a big mistake?). |
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17 | ** |
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18 | ** Pat Wood |
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19 | ** Pipeline Associates, Inc. |
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20 | ** pipeline!phw@motown.com or |
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21 | ** sun!pipeline!phw or |
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22 | ** uunet!motown!pipeline!phw |
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23 | ** |
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24 | ** 05/01/91 -- V1.0 -- first release to gcc mailing lists |
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25 | ** 05/04/91 -- V1.1 -- added float and double prototypes and return values |
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26 | ** -- fixed problems with adding and subtracting zero |
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27 | ** -- fixed rounding in truncdfsf2 |
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28 | ** -- fixed SWAP define and tested on 386 |
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29 | */ |
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30 | |
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31 | /* |
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32 | ** The following are routines that replace the gnulib soft floating point |
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33 | ** routines that are called automatically when -msoft-float is selected. |
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34 | ** The support single and double precision IEEE format, with provisions |
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35 | ** for byte-swapped machines (tested on 386). Some of the double-precision |
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36 | ** routines work at full precision, but most of the hard ones simply punt |
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37 | ** and call the single precision routines, producing a loss of accuracy. |
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38 | ** long long support is not assumed or included. |
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39 | ** Overall accuracy is close to IEEE (actually 68882) for single-precision |
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40 | ** arithmetic. I think there may still be a 1 in 1000 chance of a bit |
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41 | ** being rounded the wrong way during a multiply. I'm not fussy enough to |
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42 | ** bother with it, but if anyone is, knock yourself out. |
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43 | ** |
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44 | ** Efficiency has only been addressed where it was obvious that something |
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45 | ** would make a big difference. Anyone who wants to do this right for |
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46 | ** best speed should go in and rewrite in assembler. |
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47 | ** |
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48 | ** I have tested this only on a 68030 workstation and 386/ix integrated |
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49 | ** in with -msoft-float. |
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50 | */ |
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51 | |
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52 | /* the following deal with IEEE single-precision numbers */ |
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53 | #define EXCESS 126L |
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54 | #define SIGNBIT 0x80000000L |
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55 | #define HIDDEN (1L << 23L) |
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56 | #define SIGN(fp) ((fp) & SIGNBIT) |
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57 | #define EXP(fp) (((fp) >> 23L) & 0xFF) |
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58 | #define MANT(fp) (((fp) & 0x7FFFFFL) | HIDDEN) |
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59 | #define PACK(s,e,m) ((s) | ((e) << 23L) | (m)) |
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60 | |
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61 | /* the following deal with IEEE double-precision numbers */ |
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62 | #define EXCESSD 1022 |
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63 | #define HIDDEND (1L << 20L) |
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64 | #define EXPDBITS 11 |
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65 | #define EXPDMASK 0x7FF |
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66 | #define EXPD(fp) (((fp.l.upper) >> 20L) & 0x7FFL) |
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67 | #define SIGND(fp) ((fp.l.upper) & SIGNBIT) |
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68 | #define MANTD(fp) (((((fp.l.upper) & 0xFFFFF) | HIDDEND) << 10) | \ |
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69 | (fp.l.lower >> 22)) |
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70 | #define MANTDMASK 0xFFFFF /* mask of upper part */ |
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71 | |
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72 | /* the following deal with IEEE extended-precision numbers */ |
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73 | #define EXCESSX 16382 |
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74 | #define HIDDENX (1L << 31L) |
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75 | #define EXPXBITS 15 |
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76 | #define EXPXMASK 0x7FFF |
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77 | #define EXPX(fp) (((fp.l.upper) >> 16) & EXPXMASK) |
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78 | #define SIGNX(fp) ((fp.l.upper) & SIGNBIT) |
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79 | #define MANTXMASK 0x7FFFFFFF /* mask of upper part */ |
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80 | |
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81 | union double_long |
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82 | { |
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83 | double d; |
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84 | struct { |
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85 | long upper; |
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86 | unsigned long lower; |
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87 | } l; |
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88 | }; |
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89 | |
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90 | union float_long { |
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91 | float f; |
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92 | long l; |
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93 | }; |
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94 | |
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95 | union long_double_long |
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96 | { |
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97 | long double ld; |
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98 | struct |
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99 | { |
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100 | long upper; |
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101 | unsigned long middle; |
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102 | unsigned long lower; |
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103 | } l; |
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104 | }; |
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105 | |
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106 | #ifndef EXTFLOAT |
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107 | |
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108 | /* convert int to double */ |
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109 | double |
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110 | __floatsidf (int a1) |
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111 | { |
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112 | long sign = 0, exp = 31 + EXCESSD; |
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113 | union double_long dl; |
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114 | |
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115 | if (!a1) |
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116 | { |
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117 | dl.l.upper = dl.l.lower = 0; |
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118 | return dl.d; |
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119 | } |
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120 | |
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121 | if (a1 < 0) |
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122 | { |
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123 | sign = SIGNBIT; |
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124 | a1 = -a1; |
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125 | if (a1 < 0) |
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126 | { |
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127 | dl.l.upper = SIGNBIT | ((32 + EXCESSD) << 20L); |
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128 | dl.l.lower = 0; |
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129 | return dl.d; |
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130 | } |
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131 | } |
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132 | |
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133 | while (a1 < 0x1000000) |
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134 | { |
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135 | a1 <<= 4; |
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136 | exp -= 4; |
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137 | } |
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138 | |
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139 | while (a1 < 0x40000000) |
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140 | { |
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141 | a1 <<= 1; |
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142 | exp--; |
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143 | } |
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144 | |
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145 | /* pack up and go home */ |
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146 | dl.l.upper = sign; |
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147 | dl.l.upper |= exp << 20L; |
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148 | dl.l.upper |= (a1 >> 10L) & ~HIDDEND; |
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149 | dl.l.lower = a1 << 22L; |
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150 | |
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151 | return dl.d; |
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152 | } |
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153 | |
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154 | /* convert int to float */ |
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155 | float |
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156 | __floatsisf (int l) |
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157 | { |
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158 | double foo = __floatsidf (l); |
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159 | return foo; |
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160 | } |
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161 | |
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162 | /* convert float to double */ |
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163 | double |
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164 | __extendsfdf2 (float a1) |
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165 | { |
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166 | register union float_long fl1; |
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167 | register union double_long dl; |
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168 | register long exp; |
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169 | |
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170 | fl1.f = a1; |
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171 | |
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172 | if (!fl1.l) |
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173 | { |
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174 | dl.l.upper = dl.l.lower = 0; |
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175 | return dl.d; |
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176 | } |
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177 | |
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178 | dl.l.upper = SIGN (fl1.l); |
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179 | exp = EXP (fl1.l) - EXCESS + EXCESSD; |
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180 | dl.l.upper |= exp << 20; |
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181 | dl.l.upper |= (MANT (fl1.l) & ~HIDDEN) >> 3; |
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182 | dl.l.lower = MANT (fl1.l) << 29; |
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183 | |
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184 | return dl.d; |
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185 | } |
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186 | |
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187 | /* convert double to float */ |
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188 | float |
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189 | __truncdfsf2 (double a1) |
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190 | { |
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191 | register long exp; |
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192 | register long mant; |
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193 | register union float_long fl; |
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194 | register union double_long dl1; |
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195 | |
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196 | dl1.d = a1; |
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197 | |
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198 | if (!dl1.l.upper && !dl1.l.lower) |
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199 | return 0; |
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200 | |
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201 | exp = EXPD (dl1) - EXCESSD + EXCESS; |
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202 | |
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203 | /* shift double mantissa 6 bits so we can round */ |
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204 | mant = MANTD (dl1) >> 6; |
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205 | |
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206 | /* now round and shift down */ |
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207 | mant += 1; |
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208 | mant >>= 1; |
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209 | |
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210 | /* did the round overflow? */ |
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211 | if (mant & 0xFF000000) |
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212 | { |
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213 | mant >>= 1; |
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214 | exp++; |
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215 | } |
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216 | |
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217 | mant &= ~HIDDEN; |
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218 | |
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219 | /* pack up and go home */ |
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220 | fl.l = PACK (SIGND (dl1), exp, mant); |
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221 | return (fl.f); |
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222 | } |
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223 | |
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224 | /* convert double to int */ |
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225 | int |
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226 | __fixdfsi (double a1) |
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227 | { |
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228 | register union double_long dl1; |
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229 | register long exp; |
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230 | register long l; |
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231 | |
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232 | dl1.d = a1; |
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233 | |
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234 | if (!dl1.l.upper && !dl1.l.lower) |
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235 | return 0; |
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236 | |
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237 | exp = EXPD (dl1) - EXCESSD - 31; |
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238 | l = MANTD (dl1); |
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239 | |
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240 | if (exp > 0) |
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241 | { |
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242 | /* Return largest integer. */ |
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243 | return SIGND (dl1) ? 0x80000000 : 0x7fffffff; |
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244 | } |
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245 | |
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246 | if (exp <= -32) |
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247 | return 0; |
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248 | |
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249 | /* shift down until exp = 0 */ |
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250 | if (exp < 0) |
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251 | l >>= -exp; |
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252 | |
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253 | return (SIGND (dl1) ? -l : l); |
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254 | } |
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255 | |
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256 | /* convert float to int */ |
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257 | int |
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258 | __fixsfsi (float a1) |
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259 | { |
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260 | double foo = a1; |
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261 | return __fixdfsi (foo); |
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262 | } |
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263 | |
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264 | #else /* EXTFLOAT */ |
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265 | |
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266 | /* Primitive extended precision floating point support. |
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267 | |
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268 | We assume all numbers are normalized, don't do any rounding, etc. */ |
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269 | |
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270 | /* Prototypes for the above in case we use them. */ |
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271 | double __floatsidf (int); |
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272 | float __floatsisf (int); |
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273 | double __extendsfdf2 (float); |
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274 | float __truncdfsf2 (double); |
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275 | int __fixdfsi (double); |
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276 | int __fixsfsi (float); |
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277 | |
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278 | /* convert double to long double */ |
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279 | long double |
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280 | __extenddfxf2 (double d) |
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281 | { |
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282 | register union double_long dl; |
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283 | register union long_double_long ldl; |
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284 | register long exp; |
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285 | |
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286 | dl.d = d; |
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287 | /*printf ("dfxf in: %g\n", d);*/ |
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288 | |
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289 | if (!dl.l.upper && !dl.l.lower) |
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290 | return 0; |
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291 | |
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292 | ldl.l.upper = SIGND (dl); |
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293 | exp = EXPD (dl) - EXCESSD + EXCESSX; |
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294 | ldl.l.upper |= exp << 16; |
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295 | ldl.l.middle = HIDDENX; |
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296 | /* 31-20: # mantissa bits in ldl.l.middle - # mantissa bits in dl.l.upper */ |
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297 | ldl.l.middle |= (dl.l.upper & MANTDMASK) << (31 - 20); |
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298 | /* 1+20: explicit-integer-bit + # mantissa bits in dl.l.upper */ |
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299 | ldl.l.middle |= dl.l.lower >> (1 + 20); |
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300 | /* 32 - 21: # bits of dl.l.lower in ldl.l.middle */ |
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301 | ldl.l.lower = dl.l.lower << (32 - 21); |
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302 | |
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303 | /*printf ("dfxf out: %s\n", dumpxf (ldl.ld));*/ |
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304 | return ldl.ld; |
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305 | } |
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306 | |
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307 | /* convert long double to double */ |
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308 | double |
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309 | __truncxfdf2 (long double ld) |
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310 | { |
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311 | register long exp; |
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312 | register union double_long dl; |
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313 | register union long_double_long ldl; |
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314 | |
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315 | ldl.ld = ld; |
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316 | /*printf ("xfdf in: %s\n", dumpxf (ld));*/ |
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317 | |
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318 | if (!ldl.l.upper && !ldl.l.middle && !ldl.l.lower) |
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319 | return 0; |
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320 | |
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321 | exp = EXPX (ldl) - EXCESSX + EXCESSD; |
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322 | /* ??? quick and dirty: keep `exp' sane */ |
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323 | if (exp >= EXPDMASK) |
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324 | exp = EXPDMASK - 1; |
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325 | dl.l.upper = SIGNX (ldl); |
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326 | dl.l.upper |= exp << (32 - (EXPDBITS + 1)); |
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327 | /* +1-1: add one for sign bit, but take one off for explicit-integer-bit */ |
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328 | dl.l.upper |= (ldl.l.middle & MANTXMASK) >> (EXPDBITS + 1 - 1); |
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329 | dl.l.lower = (ldl.l.middle & MANTXMASK) << (32 - (EXPDBITS + 1 - 1)); |
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330 | dl.l.lower |= ldl.l.lower >> (EXPDBITS + 1 - 1); |
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331 | |
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332 | /*printf ("xfdf out: %g\n", dl.d);*/ |
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333 | return dl.d; |
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334 | } |
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335 | |
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336 | /* convert a float to a long double */ |
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337 | long double |
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338 | __extendsfxf2 (float f) |
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339 | { |
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340 | long double foo = __extenddfxf2 (__extendsfdf2 (f)); |
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341 | return foo; |
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342 | } |
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343 | |
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344 | /* convert a long double to a float */ |
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345 | float |
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346 | __truncxfsf2 (long double ld) |
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347 | { |
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348 | float foo = __truncdfsf2 (__truncxfdf2 (ld)); |
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349 | return foo; |
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350 | } |
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351 | |
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352 | /* convert an int to a long double */ |
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353 | long double |
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354 | __floatsixf (int l) |
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355 | { |
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356 | double foo = __floatsidf (l); |
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357 | return foo; |
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358 | } |
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359 | |
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360 | /* convert a long double to an int */ |
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361 | int |
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362 | __fixxfsi (long double ld) |
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363 | { |
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364 | int foo = __fixdfsi ((double) ld); |
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365 | return foo; |
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366 | } |
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367 | |
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368 | /* The remaining provide crude math support by working in double precision. */ |
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369 | |
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370 | long double |
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371 | __addxf3 (long double x1, long double x2) |
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372 | { |
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373 | return (double) x1 + (double) x2; |
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374 | } |
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375 | |
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376 | long double |
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377 | __subxf3 (long double x1, long double x2) |
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378 | { |
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379 | return (double) x1 - (double) x2; |
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380 | } |
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381 | |
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382 | long double |
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383 | __mulxf3 (long double x1, long double x2) |
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384 | { |
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385 | return (double) x1 * (double) x2; |
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386 | } |
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387 | |
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388 | long double |
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389 | __divxf3 (long double x1, long double x2) |
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390 | { |
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391 | return (double) x1 / (double) x2; |
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392 | } |
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393 | |
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394 | long double |
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395 | __negxf2 (long double x1) |
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396 | { |
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397 | return - (double) x1; |
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398 | } |
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399 | |
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400 | long |
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401 | __cmpxf2 (long double x1, long double x2) |
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402 | { |
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403 | return __cmpdf2 ((double) x1, (double) x2); |
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404 | } |
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405 | |
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406 | long |
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407 | __eqxf2 (long double x1, long double x2) |
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408 | { |
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409 | return __cmpdf2 ((double) x1, (double) x2); |
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410 | } |
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411 | |
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412 | long |
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413 | __nexf2 (long double x1, long double x2) |
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414 | { |
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415 | return __cmpdf2 ((double) x1, (double) x2); |
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416 | } |
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417 | |
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418 | long |
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419 | __ltxf2 (long double x1, long double x2) |
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420 | { |
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421 | return __cmpdf2 ((double) x1, (double) x2); |
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422 | } |
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423 | |
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424 | long |
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425 | __lexf2 (long double x1, long double x2) |
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426 | { |
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427 | return __cmpdf2 ((double) x1, (double) x2); |
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428 | } |
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429 | |
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430 | long |
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431 | __gtxf2 (long double x1, long double x2) |
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432 | { |
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433 | return __cmpdf2 ((double) x1, (double) x2); |
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434 | } |
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435 | |
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436 | long |
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437 | __gexf2 (long double x1, long double x2) |
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438 | { |
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439 | return __cmpdf2 ((double) x1, (double) x2); |
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440 | } |
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441 | |
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442 | #endif /* EXTFLOAT */ |
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