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5222 | serge | 1 | /* atof_ieee.c - turn a Flonum into an IEEE floating point number |
6324 | serge | 2 | Copyright (C) 1987-2015 Free Software Foundation, Inc. |
5222 | serge | 3 | |
4 | This file is part of GAS, the GNU Assembler. |
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5 | |||
6 | GAS is free software; you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation; either version 3, or (at your option) |
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9 | any later version. |
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10 | |||
11 | GAS is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License for more details. |
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15 | |||
16 | You should have received a copy of the GNU General Public License |
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17 | along with GAS; see the file COPYING. If not, write to the Free |
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18 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
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19 | 02110-1301, USA. */ |
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20 | |||
21 | #include "as.h" |
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22 | |||
23 | /* Flonums returned here. */ |
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24 | extern FLONUM_TYPE generic_floating_point_number; |
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25 | |||
26 | extern const char EXP_CHARS[]; |
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27 | /* Precision in LittleNums. */ |
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28 | /* Don't count the gap in the m68k extended precision format. */ |
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29 | #define MAX_PRECISION 5 |
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30 | #define F_PRECISION 2 |
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31 | #define D_PRECISION 4 |
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32 | #define X_PRECISION 5 |
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33 | #define P_PRECISION 5 |
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34 | |||
35 | /* Length in LittleNums of guard bits. */ |
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36 | #define GUARD 2 |
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37 | |||
38 | #ifndef TC_LARGEST_EXPONENT_IS_NORMAL |
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39 | #define TC_LARGEST_EXPONENT_IS_NORMAL(PRECISION) 0 |
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40 | #endif |
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41 | |||
42 | static const unsigned long mask[] = |
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43 | { |
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44 | 0x00000000, |
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45 | 0x00000001, |
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46 | 0x00000003, |
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47 | 0x00000007, |
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48 | 0x0000000f, |
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49 | 0x0000001f, |
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50 | 0x0000003f, |
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51 | 0x0000007f, |
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52 | 0x000000ff, |
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53 | 0x000001ff, |
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54 | 0x000003ff, |
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55 | 0x000007ff, |
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56 | 0x00000fff, |
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57 | 0x00001fff, |
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58 | 0x00003fff, |
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59 | 0x00007fff, |
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60 | 0x0000ffff, |
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61 | 0x0001ffff, |
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62 | 0x0003ffff, |
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63 | 0x0007ffff, |
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64 | 0x000fffff, |
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65 | 0x001fffff, |
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66 | 0x003fffff, |
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67 | 0x007fffff, |
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68 | 0x00ffffff, |
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69 | 0x01ffffff, |
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70 | 0x03ffffff, |
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71 | 0x07ffffff, |
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72 | 0x0fffffff, |
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73 | 0x1fffffff, |
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74 | 0x3fffffff, |
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75 | 0x7fffffff, |
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76 | 0xffffffff, |
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77 | }; |
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78 | |||
79 | static int bits_left_in_littlenum; |
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80 | static int littlenums_left; |
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81 | static LITTLENUM_TYPE *littlenum_pointer; |
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82 | |||
83 | static int |
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84 | next_bits (int number_of_bits) |
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85 | { |
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86 | int return_value; |
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87 | |||
88 | if (!littlenums_left) |
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89 | return 0; |
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90 | |||
91 | if (number_of_bits >= bits_left_in_littlenum) |
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92 | { |
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93 | return_value = mask[bits_left_in_littlenum] & *littlenum_pointer; |
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94 | number_of_bits -= bits_left_in_littlenum; |
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95 | return_value <<= number_of_bits; |
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96 | |||
97 | if (--littlenums_left) |
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98 | { |
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99 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; |
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100 | --littlenum_pointer; |
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101 | return_value |= |
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102 | (*littlenum_pointer >> bits_left_in_littlenum) |
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103 | & mask[number_of_bits]; |
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104 | } |
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105 | } |
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106 | else |
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107 | { |
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108 | bits_left_in_littlenum -= number_of_bits; |
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109 | return_value = |
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110 | mask[number_of_bits] & (*littlenum_pointer >> bits_left_in_littlenum); |
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111 | } |
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112 | return return_value; |
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113 | } |
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114 | |||
115 | /* Num had better be less than LITTLENUM_NUMBER_OF_BITS. */ |
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116 | |||
117 | static void |
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118 | unget_bits (int num) |
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119 | { |
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120 | if (!littlenums_left) |
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121 | { |
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122 | ++littlenum_pointer; |
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123 | ++littlenums_left; |
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124 | bits_left_in_littlenum = num; |
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125 | } |
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126 | else if (bits_left_in_littlenum + num > LITTLENUM_NUMBER_OF_BITS) |
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127 | { |
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128 | bits_left_in_littlenum = |
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129 | num - (LITTLENUM_NUMBER_OF_BITS - bits_left_in_littlenum); |
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130 | ++littlenum_pointer; |
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131 | ++littlenums_left; |
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132 | } |
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133 | else |
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134 | bits_left_in_littlenum += num; |
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135 | } |
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136 | |||
137 | static void |
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138 | make_invalid_floating_point_number (LITTLENUM_TYPE *words) |
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139 | { |
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140 | as_bad (_("cannot create floating-point number")); |
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141 | /* Zero the leftmost bit. */ |
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142 | words[0] = (LITTLENUM_TYPE) ((unsigned) -1) >> 1; |
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143 | words[1] = (LITTLENUM_TYPE) -1; |
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144 | words[2] = (LITTLENUM_TYPE) -1; |
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145 | words[3] = (LITTLENUM_TYPE) -1; |
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146 | words[4] = (LITTLENUM_TYPE) -1; |
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147 | words[5] = (LITTLENUM_TYPE) -1; |
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148 | } |
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149 | |||
150 | /* Warning: This returns 16-bit LITTLENUMs. It is up to the caller to |
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151 | figure out any alignment problems and to conspire for the |
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152 | bytes/word to be emitted in the right order. Bigendians beware! */ |
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153 | |||
154 | /* Note that atof-ieee always has X and P precisions enabled. it is up |
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155 | to md_atof to filter them out if the target machine does not support |
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156 | them. */ |
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157 | |||
158 | /* Returns pointer past text consumed. */ |
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159 | |||
160 | char * |
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161 | atof_ieee (char *str, /* Text to convert to binary. */ |
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162 | int what_kind, /* 'd', 'f', 'x', 'p'. */ |
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163 | LITTLENUM_TYPE *words) /* Build the binary here. */ |
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164 | { |
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165 | /* Extra bits for zeroed low-order bits. |
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166 | The 1st MAX_PRECISION are zeroed, the last contain flonum bits. */ |
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167 | static LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD]; |
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168 | char *return_value; |
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169 | /* Number of 16-bit words in the format. */ |
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170 | int precision; |
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171 | long exponent_bits; |
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172 | FLONUM_TYPE save_gen_flonum; |
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173 | |||
174 | /* We have to save the generic_floating_point_number because it |
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175 | contains storage allocation about the array of LITTLENUMs where |
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176 | the value is actually stored. We will allocate our own array of |
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177 | littlenums below, but have to restore the global one on exit. */ |
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178 | save_gen_flonum = generic_floating_point_number; |
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179 | |||
180 | return_value = str; |
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181 | generic_floating_point_number.low = bits + MAX_PRECISION; |
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182 | generic_floating_point_number.high = NULL; |
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183 | generic_floating_point_number.leader = NULL; |
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184 | generic_floating_point_number.exponent = 0; |
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185 | generic_floating_point_number.sign = '\0'; |
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186 | |||
187 | /* Use more LittleNums than seems necessary: the highest flonum may |
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188 | have 15 leading 0 bits, so could be useless. */ |
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189 | |||
190 | memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION); |
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191 | |||
192 | switch (what_kind) |
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193 | { |
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194 | case 'f': |
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195 | case 'F': |
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196 | case 's': |
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197 | case 'S': |
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198 | precision = F_PRECISION; |
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199 | exponent_bits = 8; |
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200 | break; |
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201 | |||
202 | case 'd': |
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203 | case 'D': |
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204 | case 'r': |
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205 | case 'R': |
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206 | precision = D_PRECISION; |
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207 | exponent_bits = 11; |
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208 | break; |
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209 | |||
210 | case 'x': |
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211 | case 'X': |
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212 | case 'e': |
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213 | case 'E': |
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214 | precision = X_PRECISION; |
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215 | exponent_bits = 15; |
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216 | break; |
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217 | |||
218 | case 'p': |
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219 | case 'P': |
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220 | precision = P_PRECISION; |
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221 | exponent_bits = -1; |
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222 | break; |
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223 | |||
224 | default: |
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225 | make_invalid_floating_point_number (words); |
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226 | return (NULL); |
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227 | } |
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228 | |||
229 | generic_floating_point_number.high |
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230 | = generic_floating_point_number.low + precision - 1 + GUARD; |
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231 | |||
232 | if (atof_generic (&return_value, ".", EXP_CHARS, |
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233 | &generic_floating_point_number)) |
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234 | { |
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235 | make_invalid_floating_point_number (words); |
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236 | return NULL; |
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237 | } |
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238 | gen_to_words (words, precision, exponent_bits); |
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239 | |||
240 | /* Restore the generic_floating_point_number's storage alloc (and |
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241 | everything else). */ |
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242 | generic_floating_point_number = save_gen_flonum; |
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243 | |||
244 | return return_value; |
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245 | } |
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246 | |||
247 | /* Turn generic_floating_point_number into a real float/double/extended. */ |
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248 | |||
249 | int |
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250 | gen_to_words (LITTLENUM_TYPE *words, int precision, long exponent_bits) |
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251 | { |
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252 | int return_value = 0; |
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253 | |||
254 | long exponent_1; |
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255 | long exponent_2; |
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256 | long exponent_3; |
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257 | long exponent_4; |
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258 | int exponent_skippage; |
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259 | LITTLENUM_TYPE word1; |
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260 | LITTLENUM_TYPE *lp; |
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261 | LITTLENUM_TYPE *words_end; |
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262 | |||
263 | words_end = words + precision; |
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264 | #ifdef TC_M68K |
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265 | if (precision == X_PRECISION) |
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266 | /* On the m68k the extended precision format has a gap of 16 bits |
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267 | between the exponent and the mantissa. */ |
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268 | words_end++; |
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269 | #endif |
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270 | |||
271 | if (generic_floating_point_number.low > generic_floating_point_number.leader) |
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272 | { |
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273 | /* 0.0e0 seen. */ |
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274 | if (generic_floating_point_number.sign == '+') |
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275 | words[0] = 0x0000; |
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276 | else |
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277 | words[0] = 0x8000; |
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278 | memset (&words[1], '\0', |
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279 | (words_end - words - 1) * sizeof (LITTLENUM_TYPE)); |
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280 | return return_value; |
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281 | } |
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282 | |||
283 | /* NaN: Do the right thing. */ |
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284 | if (generic_floating_point_number.sign == 0) |
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285 | { |
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286 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
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287 | as_warn (_("NaNs are not supported by this target\n")); |
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288 | if (precision == F_PRECISION) |
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289 | { |
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290 | words[0] = 0x7fff; |
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291 | words[1] = 0xffff; |
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292 | } |
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293 | else if (precision == X_PRECISION) |
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294 | { |
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295 | #ifdef TC_M68K |
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296 | words[0] = 0x7fff; |
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297 | words[1] = 0; |
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298 | words[2] = 0xffff; |
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299 | words[3] = 0xffff; |
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300 | words[4] = 0xffff; |
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301 | words[5] = 0xffff; |
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302 | #else /* ! TC_M68K */ |
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303 | #ifdef TC_I386 |
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304 | words[0] = 0xffff; |
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305 | words[1] = 0xc000; |
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306 | words[2] = 0; |
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307 | words[3] = 0; |
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308 | words[4] = 0; |
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309 | #else /* ! TC_I386 */ |
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310 | abort (); |
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311 | #endif /* ! TC_I386 */ |
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312 | #endif /* ! TC_M68K */ |
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313 | } |
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314 | else |
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315 | { |
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316 | words[0] = 0x7fff; |
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317 | words[1] = 0xffff; |
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318 | words[2] = 0xffff; |
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319 | words[3] = 0xffff; |
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320 | } |
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321 | return return_value; |
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322 | } |
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323 | else if (generic_floating_point_number.sign == 'P') |
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324 | { |
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325 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
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326 | as_warn (_("Infinities are not supported by this target\n")); |
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327 | |||
328 | /* +INF: Do the right thing. */ |
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329 | if (precision == F_PRECISION) |
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330 | { |
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331 | words[0] = 0x7f80; |
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332 | words[1] = 0; |
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333 | } |
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334 | else if (precision == X_PRECISION) |
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335 | { |
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336 | #ifdef TC_M68K |
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337 | words[0] = 0x7fff; |
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338 | words[1] = 0; |
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339 | words[2] = 0; |
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340 | words[3] = 0; |
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341 | words[4] = 0; |
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342 | words[5] = 0; |
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343 | #else /* ! TC_M68K */ |
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344 | #ifdef TC_I386 |
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345 | words[0] = 0x7fff; |
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346 | words[1] = 0x8000; |
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347 | words[2] = 0; |
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348 | words[3] = 0; |
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349 | words[4] = 0; |
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350 | #else /* ! TC_I386 */ |
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351 | abort (); |
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352 | #endif /* ! TC_I386 */ |
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353 | #endif /* ! TC_M68K */ |
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354 | } |
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355 | else |
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356 | { |
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357 | words[0] = 0x7ff0; |
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358 | words[1] = 0; |
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359 | words[2] = 0; |
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360 | words[3] = 0; |
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361 | } |
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362 | return return_value; |
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363 | } |
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364 | else if (generic_floating_point_number.sign == 'N') |
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365 | { |
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366 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
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367 | as_warn (_("Infinities are not supported by this target\n")); |
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368 | |||
369 | /* Negative INF. */ |
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370 | if (precision == F_PRECISION) |
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371 | { |
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372 | words[0] = 0xff80; |
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373 | words[1] = 0x0; |
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374 | } |
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375 | else if (precision == X_PRECISION) |
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376 | { |
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377 | #ifdef TC_M68K |
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378 | words[0] = 0xffff; |
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379 | words[1] = 0; |
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380 | words[2] = 0; |
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381 | words[3] = 0; |
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382 | words[4] = 0; |
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383 | words[5] = 0; |
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384 | #else /* ! TC_M68K */ |
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385 | #ifdef TC_I386 |
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386 | words[0] = 0xffff; |
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387 | words[1] = 0x8000; |
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388 | words[2] = 0; |
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389 | words[3] = 0; |
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390 | words[4] = 0; |
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391 | #else /* ! TC_I386 */ |
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392 | abort (); |
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393 | #endif /* ! TC_I386 */ |
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394 | #endif /* ! TC_M68K */ |
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395 | } |
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396 | else |
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397 | { |
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398 | words[0] = 0xfff0; |
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399 | words[1] = 0x0; |
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400 | words[2] = 0x0; |
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401 | words[3] = 0x0; |
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402 | } |
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403 | return return_value; |
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404 | } |
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405 | |||
406 | /* The floating point formats we support have: |
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407 | Bit 15 is sign bit. |
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408 | Bits 14:n are excess-whatever exponent. |
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409 | Bits n-1:0 (if any) are most significant bits of fraction. |
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410 | Bits 15:0 of the next word(s) are the next most significant bits. |
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411 | |||
412 | So we need: number of bits of exponent, number of bits of |
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413 | mantissa. */ |
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414 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; |
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415 | littlenum_pointer = generic_floating_point_number.leader; |
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416 | littlenums_left = (1 |
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417 | + generic_floating_point_number.leader |
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418 | - generic_floating_point_number.low); |
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419 | |||
420 | /* Seek (and forget) 1st significant bit. */ |
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421 | for (exponent_skippage = 0; !next_bits (1); ++exponent_skippage); |
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422 | exponent_1 = (generic_floating_point_number.exponent |
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423 | + generic_floating_point_number.leader |
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424 | + 1 |
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425 | - generic_floating_point_number.low); |
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426 | |||
427 | /* Radix LITTLENUM_RADIX, point just higher than |
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428 | generic_floating_point_number.leader. */ |
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429 | exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS; |
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430 | |||
431 | /* Radix 2. */ |
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432 | exponent_3 = exponent_2 - exponent_skippage; |
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433 | |||
434 | /* Forget leading zeros, forget 1st bit. */ |
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435 | exponent_4 = exponent_3 + ((1 << (exponent_bits - 1)) - 2); |
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436 | |||
437 | /* Offset exponent. */ |
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438 | lp = words; |
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439 | |||
440 | /* Word 1. Sign, exponent and perhaps high bits. */ |
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441 | word1 = ((generic_floating_point_number.sign == '+') |
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442 | ? 0 |
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443 | : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); |
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444 | |||
445 | /* Assume 2's complement integers. */ |
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446 | if (exponent_4 <= 0) |
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447 | { |
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448 | int prec_bits; |
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449 | int num_bits; |
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450 | |||
451 | unget_bits (1); |
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452 | num_bits = -exponent_4; |
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453 | prec_bits = |
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454 | LITTLENUM_NUMBER_OF_BITS * precision - (exponent_bits + 1 + num_bits); |
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455 | #ifdef TC_I386 |
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456 | if (precision == X_PRECISION && exponent_bits == 15) |
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457 | { |
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458 | /* On the i386 a denormalized extended precision float is |
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459 | shifted down by one, effectively decreasing the exponent |
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460 | bias by one. */ |
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461 | prec_bits -= 1; |
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462 | num_bits += 1; |
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463 | } |
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464 | #endif |
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465 | |||
466 | if (num_bits >= LITTLENUM_NUMBER_OF_BITS - exponent_bits) |
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467 | { |
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468 | /* Bigger than one littlenum. */ |
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469 | num_bits -= (LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits; |
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470 | *lp++ = word1; |
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471 | if (num_bits + exponent_bits + 1 |
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472 | > precision * LITTLENUM_NUMBER_OF_BITS) |
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473 | { |
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474 | /* Exponent overflow. */ |
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475 | make_invalid_floating_point_number (words); |
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476 | return return_value; |
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477 | } |
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478 | #ifdef TC_M68K |
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479 | if (precision == X_PRECISION && exponent_bits == 15) |
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480 | *lp++ = 0; |
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481 | #endif |
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482 | while (num_bits >= LITTLENUM_NUMBER_OF_BITS) |
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483 | { |
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484 | num_bits -= LITTLENUM_NUMBER_OF_BITS; |
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485 | *lp++ = 0; |
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486 | } |
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487 | if (num_bits) |
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488 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - (num_bits)); |
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489 | } |
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490 | else |
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491 | { |
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492 | if (precision == X_PRECISION && exponent_bits == 15) |
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493 | { |
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494 | *lp++ = word1; |
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495 | #ifdef TC_M68K |
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496 | *lp++ = 0; |
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497 | #endif |
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498 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - num_bits); |
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499 | } |
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500 | else |
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501 | { |
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502 | word1 |= next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) |
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503 | - (exponent_bits + num_bits)); |
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504 | *lp++ = word1; |
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505 | } |
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506 | } |
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507 | while (lp < words_end) |
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508 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); |
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509 | |||
510 | /* Round the mantissa up, but don't change the number. */ |
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511 | if (next_bits (1)) |
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512 | { |
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513 | --lp; |
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514 | if (prec_bits >= LITTLENUM_NUMBER_OF_BITS) |
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515 | { |
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516 | int n = 0; |
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517 | int tmp_bits; |
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518 | |||
519 | n = 0; |
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520 | tmp_bits = prec_bits; |
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521 | while (tmp_bits > LITTLENUM_NUMBER_OF_BITS) |
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522 | { |
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523 | if (lp[n] != (LITTLENUM_TYPE) - 1) |
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524 | break; |
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525 | --n; |
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526 | tmp_bits -= LITTLENUM_NUMBER_OF_BITS; |
||
527 | } |
||
528 | if (tmp_bits > LITTLENUM_NUMBER_OF_BITS |
||
529 | || (lp[n] & mask[tmp_bits]) != mask[tmp_bits] |
||
530 | || (prec_bits != (precision * LITTLENUM_NUMBER_OF_BITS |
||
531 | - exponent_bits - 1) |
||
532 | #ifdef TC_I386 |
||
533 | /* An extended precision float with only the integer |
||
534 | bit set would be invalid. That must be converted |
||
535 | to the smallest normalized number. */ |
||
536 | && !(precision == X_PRECISION |
||
537 | && prec_bits == (precision * LITTLENUM_NUMBER_OF_BITS |
||
538 | - exponent_bits - 2)) |
||
539 | #endif |
||
540 | )) |
||
541 | { |
||
542 | unsigned long carry; |
||
543 | |||
544 | for (carry = 1; carry && (lp >= words); lp--) |
||
545 | { |
||
546 | carry = *lp + carry; |
||
547 | *lp = carry; |
||
548 | carry >>= LITTLENUM_NUMBER_OF_BITS; |
||
549 | } |
||
550 | } |
||
551 | else |
||
552 | { |
||
553 | /* This is an overflow of the denormal numbers. We |
||
554 | need to forget what we have produced, and instead |
||
555 | generate the smallest normalized number. */ |
||
556 | lp = words; |
||
557 | word1 = ((generic_floating_point_number.sign == '+') |
||
558 | ? 0 |
||
559 | : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); |
||
560 | word1 |= (1 |
||
561 | << ((LITTLENUM_NUMBER_OF_BITS - 1) |
||
562 | - exponent_bits)); |
||
563 | *lp++ = word1; |
||
564 | #ifdef TC_I386 |
||
565 | /* Set the integer bit in the extended precision format. |
||
566 | This cannot happen on the m68k where the mantissa |
||
567 | just overflows into the integer bit above. */ |
||
568 | if (precision == X_PRECISION) |
||
569 | *lp++ = 1 << (LITTLENUM_NUMBER_OF_BITS - 1); |
||
570 | #endif |
||
571 | while (lp < words_end) |
||
572 | *lp++ = 0; |
||
573 | } |
||
574 | } |
||
575 | else |
||
576 | *lp += 1; |
||
577 | } |
||
578 | |||
579 | return return_value; |
||
580 | } |
||
581 | else if ((unsigned long) exponent_4 > mask[exponent_bits] |
||
582 | || (! TC_LARGEST_EXPONENT_IS_NORMAL (precision) |
||
583 | && (unsigned long) exponent_4 == mask[exponent_bits])) |
||
584 | { |
||
585 | /* Exponent overflow. Lose immediately. */ |
||
586 | |||
587 | /* We leave return_value alone: admit we read the |
||
588 | number, but return a floating exception |
||
589 | because we can't encode the number. */ |
||
590 | make_invalid_floating_point_number (words); |
||
591 | return return_value; |
||
592 | } |
||
593 | else |
||
594 | { |
||
595 | word1 |= (exponent_4 << ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits)) |
||
596 | | next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits); |
||
597 | } |
||
598 | |||
599 | *lp++ = word1; |
||
600 | |||
601 | /* X_PRECISION is special: on the 68k, it has 16 bits of zero in the |
||
602 | middle. Either way, it is then followed by a 1 bit. */ |
||
603 | if (exponent_bits == 15 && precision == X_PRECISION) |
||
604 | { |
||
605 | #ifdef TC_M68K |
||
606 | *lp++ = 0; |
||
607 | #endif |
||
608 | *lp++ = (1 << (LITTLENUM_NUMBER_OF_BITS - 1) |
||
609 | | next_bits (LITTLENUM_NUMBER_OF_BITS - 1)); |
||
610 | } |
||
611 | |||
612 | /* The rest of the words are just mantissa bits. */ |
||
613 | while (lp < words_end) |
||
614 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); |
||
615 | |||
616 | if (next_bits (1)) |
||
617 | { |
||
618 | unsigned long carry; |
||
619 | /* Since the NEXT bit is a 1, round UP the mantissa. |
||
620 | The cunning design of these hidden-1 floats permits |
||
621 | us to let the mantissa overflow into the exponent, and |
||
622 | it 'does the right thing'. However, we lose if the |
||
623 | highest-order bit of the lowest-order word flips. |
||
624 | Is that clear? */ |
||
625 | |||
626 | /* #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2) |
||
627 | Please allow at least 1 more bit in carry than is in a LITTLENUM. |
||
628 | We need that extra bit to hold a carry during a LITTLENUM carry |
||
629 | propagation. Another extra bit (kept 0) will assure us that we |
||
630 | don't get a sticky sign bit after shifting right, and that |
||
631 | permits us to propagate the carry without any masking of bits. |
||
632 | #endif */ |
||
633 | for (carry = 1, lp--; carry; lp--) |
||
634 | { |
||
635 | carry = *lp + carry; |
||
636 | *lp = carry; |
||
637 | carry >>= LITTLENUM_NUMBER_OF_BITS; |
||
638 | if (lp == words) |
||
639 | break; |
||
640 | } |
||
641 | if (precision == X_PRECISION && exponent_bits == 15) |
||
642 | { |
||
643 | /* Extended precision numbers have an explicit integer bit |
||
644 | that we may have to restore. */ |
||
645 | if (lp == words) |
||
646 | { |
||
647 | #ifdef TC_M68K |
||
648 | /* On the m68k there is a gap of 16 bits. We must |
||
649 | explicitly propagate the carry into the exponent. */ |
||
650 | words[0] += words[1]; |
||
651 | words[1] = 0; |
||
652 | lp++; |
||
653 | #endif |
||
654 | /* Put back the integer bit. */ |
||
655 | lp[1] |= 1 << (LITTLENUM_NUMBER_OF_BITS - 1); |
||
656 | } |
||
657 | } |
||
658 | if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1))) |
||
659 | { |
||
660 | /* We leave return_value alone: admit we read the number, |
||
661 | but return a floating exception because we can't encode |
||
662 | the number. */ |
||
663 | *words &= ~(1 << (LITTLENUM_NUMBER_OF_BITS - 1)); |
||
664 | } |
||
665 | } |
||
666 | return return_value; |
||
667 | } |
||
668 | |||
669 | #ifdef TEST |
||
670 | char * |
||
671 | print_gen (gen) |
||
672 | FLONUM_TYPE *gen; |
||
673 | { |
||
674 | FLONUM_TYPE f; |
||
675 | LITTLENUM_TYPE arr[10]; |
||
676 | double dv; |
||
677 | float fv; |
||
678 | static char sbuf[40]; |
||
679 | |||
680 | if (gen) |
||
681 | { |
||
682 | f = generic_floating_point_number; |
||
683 | generic_floating_point_number = *gen; |
||
684 | } |
||
685 | gen_to_words (&arr[0], 4, 11); |
||
686 | memcpy (&dv, &arr[0], sizeof (double)); |
||
687 | sprintf (sbuf, "%x %x %x %x %.14G ", arr[0], arr[1], arr[2], arr[3], dv); |
||
688 | gen_to_words (&arr[0], 2, 8); |
||
689 | memcpy (&fv, &arr[0], sizeof (float)); |
||
690 | sprintf (sbuf + strlen (sbuf), "%x %x %.12g\n", arr[0], arr[1], fv); |
||
691 | |||
692 | if (gen) |
||
693 | generic_floating_point_number = f; |
||
694 | |||
695 | return (sbuf); |
||
696 | } |
||
697 | #endif |
||
698 | |||
699 | extern const char FLT_CHARS[]; |
||
700 | #define MAX_LITTLENUMS 6 |
||
701 | |||
702 | /* This is a utility function called from various tc-*.c files. It |
||
703 | is here in order to reduce code duplication. |
||
6324 | serge | 704 | |
5222 | serge | 705 | Turn a string at input_line_pointer into a floating point constant |
706 | of type TYPE (a character found in the FLT_CHARS macro), and store |
||
707 | it as LITTLENUMS in the bytes buffer LITP. The number of chars |
||
708 | emitted is stored in *SIZEP. BIG_WORDIAN is TRUE if the littlenums |
||
709 | should be emitted most significant littlenum first. |
||
710 | |||
711 | An error message is returned, or a NULL pointer if everything went OK. */ |
||
712 | |||
713 | char * |
||
714 | ieee_md_atof (int type, |
||
715 | char *litP, |
||
716 | int *sizeP, |
||
717 | bfd_boolean big_wordian) |
||
718 | { |
||
719 | LITTLENUM_TYPE words[MAX_LITTLENUMS]; |
||
720 | LITTLENUM_TYPE *wordP; |
||
721 | char *t; |
||
722 | int prec = 0; |
||
723 | |||
724 | if (strchr (FLT_CHARS, type) != NULL) |
||
725 | { |
||
726 | switch (type) |
||
727 | { |
||
728 | case 'f': |
||
729 | case 'F': |
||
730 | case 's': |
||
731 | case 'S': |
||
732 | prec = F_PRECISION; |
||
733 | break; |
||
734 | |||
735 | case 'd': |
||
736 | case 'D': |
||
737 | case 'r': |
||
738 | case 'R': |
||
739 | prec = D_PRECISION; |
||
740 | break; |
||
741 | |||
742 | case 't': |
||
743 | case 'T': |
||
744 | prec = X_PRECISION; |
||
745 | type = 'x'; /* This is what atof_ieee() understands. */ |
||
746 | break; |
||
747 | |||
748 | case 'x': |
||
749 | case 'X': |
||
750 | case 'p': |
||
751 | case 'P': |
||
752 | #ifdef TC_M68K |
||
753 | /* Note: on the m68k there is a gap of 16 bits (one littlenum) |
||
754 | between the exponent and mantissa. Hence the precision is |
||
755 | 6 and not 5. */ |
||
756 | prec = P_PRECISION + 1; |
||
757 | #else |
||
758 | prec = P_PRECISION; |
||
759 | #endif |
||
760 | break; |
||
761 | |||
762 | default: |
||
763 | break; |
||
764 | } |
||
765 | } |
||
766 | /* The 'f' and 'd' types are always recognised, even if the target has |
||
767 | not put them into the FLT_CHARS macro. This is because the 'f' type |
||
768 | can come from the .dc.s, .dcb.s, .float or .single pseudo-ops and the |
||
769 | 'd' type from the .dc.d, .dbc.d or .double pseudo-ops. |
||
770 | |||
771 | The 'x' type is not implicitly recongised however, even though it can |
||
772 | be generated by the .dc.x and .dbc.x pseudo-ops because not all targets |
||
773 | can support floating point values that big. ie the target has to |
||
774 | explicitly allow them by putting them into FLT_CHARS. */ |
||
775 | else if (type == 'f') |
||
776 | prec = F_PRECISION; |
||
777 | else if (type == 'd') |
||
778 | prec = D_PRECISION; |
||
779 | |||
780 | if (prec == 0) |
||
781 | { |
||
782 | *sizeP = 0; |
||
783 | return _("Unrecognized or unsupported floating point constant"); |
||
784 | } |
||
785 | |||
786 | gas_assert (prec <= MAX_LITTLENUMS); |
||
787 | |||
788 | t = atof_ieee (input_line_pointer, type, words); |
||
789 | if (t) |
||
790 | input_line_pointer = t; |
||
791 | |||
792 | *sizeP = prec * sizeof (LITTLENUM_TYPE); |
||
793 | |||
794 | if (big_wordian) |
||
795 | { |
||
796 | for (wordP = words; prec --;) |
||
797 | { |
||
798 | md_number_to_chars (litP, (valueT) (* wordP ++), sizeof (LITTLENUM_TYPE)); |
||
799 | litP += sizeof (LITTLENUM_TYPE); |
||
800 | } |
||
801 | } |
||
802 | else |
||
803 | { |
||
804 | for (wordP = words + prec; prec --;) |
||
805 | { |
||
806 | md_number_to_chars (litP, (valueT) (* -- wordP), sizeof (LITTLENUM_TYPE)); |
||
807 | litP += sizeof (LITTLENUM_TYPE); |
||
808 | } |
||
809 | } |
||
810 | |||
811 | return NULL; |
||
812 | }=>><>><>><>>>><>><>>><>><>><>>=>><>><>=><=> |