1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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4 | */
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5 |
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6 | #include "libbb.h"
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7 | #include "common_bufsiz.h"
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8 | #include <math.h>
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9 |
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10 | //usage:#define dc_trivial_usage
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11 | //usage: "EXPRESSION..."
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12 | //usage:
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13 | //usage:#define dc_full_usage "\n\n"
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14 | //usage: "Tiny RPN calculator. Operations:\n"
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15 | //usage: "+, add, -, sub, *, mul, /, div, %, mod, "IF_FEATURE_DC_LIBM("**, exp, ")"and, or, not, xor,\n"
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16 | //usage: "p - print top of the stack (without popping),\n"
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17 | //usage: "f - print entire stack,\n"
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18 | //usage: "o - pop the value and set output radix (must be 10, 16, 8 or 2).\n"
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19 | //usage: "Examples: 'dc 2 2 add p' -> 4, 'dc 8 8 mul 2 2 + / p' -> 16"
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20 | //usage:
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21 | //usage:#define dc_example_usage
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22 | //usage: "$ dc 2 2 + p\n"
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23 | //usage: "4\n"
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24 | //usage: "$ dc 8 8 \\* 2 2 + / p\n"
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25 | //usage: "16\n"
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26 | //usage: "$ dc 0 1 and p\n"
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27 | //usage: "0\n"
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28 | //usage: "$ dc 0 1 or p\n"
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29 | //usage: "1\n"
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30 | //usage: "$ echo 72 9 div 8 mul p | dc\n"
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31 | //usage: "64\n"
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32 |
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33 | #if 0
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34 | typedef unsigned data_t;
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35 | #define DATA_FMT ""
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36 | #elif 0
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37 | typedef unsigned long data_t;
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38 | #define DATA_FMT "l"
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39 | #else
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40 | typedef unsigned long long data_t;
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41 | #define DATA_FMT "ll"
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42 | #endif
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43 |
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44 |
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45 | struct globals {
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46 | unsigned pointer;
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47 | unsigned base;
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48 | double stack[1];
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49 | } FIX_ALIASING;
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50 | enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(double) };
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51 | #define G (*(struct globals*)bb_common_bufsiz1)
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52 | #define pointer (G.pointer )
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53 | #define base (G.base )
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54 | #define stack (G.stack )
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55 | #define INIT_G() do { \
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56 | setup_common_bufsiz(); \
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57 | base = 10; \
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58 | } while (0)
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59 |
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60 |
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61 | static void check_under(void)
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62 | {
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63 | if (pointer == 0)
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64 | bb_error_msg_and_die("stack underflow");
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65 | }
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66 |
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67 | static void push(double a)
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68 | {
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69 | if (pointer >= STACK_SIZE)
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70 | bb_error_msg_and_die("stack overflow");
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71 | stack[pointer++] = a;
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72 | }
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73 |
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74 | static double pop(void)
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75 | {
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76 | check_under();
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77 | return stack[--pointer];
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78 | }
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79 |
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80 | static void add(void)
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81 | {
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82 | push(pop() + pop());
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83 | }
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84 |
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85 | static void sub(void)
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86 | {
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87 | double subtrahend = pop();
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88 |
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89 | push(pop() - subtrahend);
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90 | }
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91 |
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92 | static void mul(void)
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93 | {
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94 | push(pop() * pop());
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95 | }
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96 |
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97 | #if ENABLE_FEATURE_DC_LIBM
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98 | static void power(void)
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99 | {
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100 | double topower = pop();
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101 |
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102 | push(pow(pop(), topower));
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103 | }
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104 | #endif
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105 |
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106 | static void divide(void)
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107 | {
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108 | double divisor = pop();
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109 |
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110 | push(pop() / divisor);
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111 | }
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112 |
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113 | static void mod(void)
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114 | {
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115 | data_t d = pop();
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116 |
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117 | push((data_t) pop() % d);
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118 | }
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119 |
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120 | static void and(void)
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121 | {
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122 | push((data_t) pop() & (data_t) pop());
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123 | }
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124 |
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125 | static void or(void)
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126 | {
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127 | push((data_t) pop() | (data_t) pop());
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128 | }
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129 |
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130 | static void eor(void)
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131 | {
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132 | push((data_t) pop() ^ (data_t) pop());
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133 | }
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134 |
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135 | static void not(void)
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136 | {
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137 | push(~(data_t) pop());
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138 | }
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139 |
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140 | static void set_output_base(void)
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141 | {
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142 | static const char bases[] ALIGN1 = { 2, 8, 10, 16, 0 };
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143 | unsigned b = (unsigned)pop();
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144 |
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145 | base = *strchrnul(bases, b);
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146 | if (base == 0) {
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147 | bb_error_msg("error, base %u is not supported", b);
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148 | base = 10;
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149 | }
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150 | }
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151 |
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152 | static void print_base(double print)
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153 | {
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154 | data_t x, i;
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155 |
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156 | x = (data_t) print;
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157 | if (base == 10) {
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158 | if (x == print) /* exactly representable as unsigned integer */
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159 | printf("%"DATA_FMT"u\n", x);
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160 | else
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161 | printf("%g\n", print);
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162 | return;
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163 | }
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164 |
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165 | switch (base) {
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166 | case 16:
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167 | printf("%"DATA_FMT"x\n", x);
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168 | break;
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169 | case 8:
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170 | printf("%"DATA_FMT"o\n", x);
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171 | break;
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172 | default: /* base 2 */
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173 | i = MAXINT(data_t) - (MAXINT(data_t) >> 1);
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174 | /* i is 100000...00000 */
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175 | do {
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176 | if (x & i)
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177 | break;
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178 | i >>= 1;
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179 | } while (i > 1);
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180 | do {
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181 | bb_putchar('1' - !(x & i));
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182 | i >>= 1;
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183 | } while (i);
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184 | bb_putchar('\n');
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185 | }
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186 | }
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187 |
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188 | static void print_stack_no_pop(void)
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189 | {
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190 | unsigned i = pointer;
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191 | while (i)
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192 | print_base(stack[--i]);
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193 | }
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194 |
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195 | static void print_no_pop(void)
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196 | {
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197 | check_under();
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198 | print_base(stack[pointer-1]);
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199 | }
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200 |
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201 | struct op {
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202 | const char name[4];
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203 | void (*function) (void);
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204 | };
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205 |
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206 | static const struct op operators[] = {
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207 | #if ENABLE_FEATURE_DC_LIBM
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208 | {"**", power},
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209 | {"exp", power},
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210 | {"pow", power},
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211 | #endif
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212 | {"%", mod},
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213 | {"mod", mod},
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214 | {"and", and},
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215 | {"or", or},
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216 | {"not", not},
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217 | {"eor", eor},
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218 | {"xor", eor},
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219 | {"+", add},
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220 | {"add", add},
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221 | {"-", sub},
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222 | {"sub", sub},
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223 | {"*", mul},
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224 | {"mul", mul},
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225 | {"/", divide},
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226 | {"div", divide},
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227 | {"p", print_no_pop},
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228 | {"f", print_stack_no_pop},
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229 | {"o", set_output_base},
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230 | };
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231 |
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232 | /* Feed the stack machine */
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233 | static void stack_machine(const char *argument)
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234 | {
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235 | char *end;
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236 | double number;
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237 | const struct op *o;
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238 |
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239 | next:
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240 | number = strtod(argument, &end);
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241 | if (end != argument) {
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242 | argument = end;
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243 | push(number);
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244 | goto next;
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245 | }
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246 |
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247 | /* We might have matched a digit, eventually advance the argument */
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248 | argument = skip_whitespace(argument);
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249 |
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250 | if (*argument == '\0')
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251 | return;
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252 |
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253 | o = operators;
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254 | do {
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255 | char *after_name = is_prefixed_with(argument, o->name);
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256 | if (after_name) {
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257 | argument = after_name;
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258 | o->function();
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259 | goto next;
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260 | }
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261 | o++;
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262 | } while (o != operators + ARRAY_SIZE(operators));
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263 |
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264 | bb_error_msg_and_die("syntax error at '%s'", argument);
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265 | }
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266 |
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267 | int dc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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268 | int dc_main(int argc UNUSED_PARAM, char **argv)
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269 | {
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270 | INIT_G();
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271 |
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272 | argv++;
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273 | if (!argv[0]) {
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274 | /* take stuff from stdin if no args are given */
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275 | char *line;
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276 | while ((line = xmalloc_fgetline(stdin)) != NULL) {
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277 | stack_machine(line);
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278 | free(line);
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279 | }
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280 | } else {
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281 | do {
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282 | stack_machine(*argv);
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283 | } while (*++argv);
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284 | }
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285 | return EXIT_SUCCESS;
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286 | }
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