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1 /*
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2 * insn_gen.c
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3 *
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4 * parsing general addressing modes (IMM+DIR+EXT+IND)
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5 */
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6
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7 #include <ctype.h>
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8 #include "lwasm.h"
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9 #include "instab.h"
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10
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11 extern void insn_indexed_aux(asmstate_t *as, sourceline_t *cl, char **optr, int *b1, int *b2, int *b3);
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12
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13 void insn_gen_aux(asmstate_t *as, sourceline_t *cl, char **optr, int *b1, int *b2, int *b3, int *op)
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14 {
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15 *b1 = *b2 = *b3 = -1;
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16 char *optr2;
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17 int v1, tv, rval;
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18
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19 optr2 = *optr;
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20 while (*optr2 && !isspace(*optr2) && *optr2 != ',') optr2++
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21 ;
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22 if (*optr2 != ',' && **optr != '[')
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23 {
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24 // not indexed
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25 if (**optr == '<')
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26 {
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27 (*optr)++;
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28 rval = eval_expr(as, cl, optr, &v1);
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29 v1 = v1 & 0xffff;
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30 tv = v1 - ((cl -> dpval) << 8);
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31 if (tv < 0 || tv > 0xff)
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32 {
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33 errorp2(ERR_OVERFLOW);
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34 }
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35 v1 = v1 & 0xff;
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36 goto ins_gen_dir;
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37 }
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38 else if (**optr == '>')
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39 {
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40 // extended mode
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41 (*optr)++;
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42 rval = eval_expr(as, cl, optr, &v1);
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43 goto ins_gen_ext;
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44 }
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45 else
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46 {
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47 // eval expr and see how big it is
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48 rval = eval_expr(as, cl, optr, &v1);
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49 v1 = v1 & 0xFFFF;
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50
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51 if (cl -> undef && as -> passnum == 1)
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52 {
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53 cl -> p1f16 = 1;
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54 goto ins_gen_ext;
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55 }
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56
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57 tv = v1 - (cl -> dpval << 8);
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58
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59 if (tv < 0 || tv > 0xff || cl -> p1f16)
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60 goto ins_gen_ext;
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61 else
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62 {
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63 v1 = v1 & 0xff;
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64 goto ins_gen_dir;
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65 }
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66 }
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67 return;
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68 }
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69
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70 *op = instab[cl -> opcode].ops[1];
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71 insn_indexed_aux(as, cl, optr, b1, b2, b3);
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72 return;
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73
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74 ins_gen_dir:
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75 *op = instab[cl -> opcode].ops[0];
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76 // cl -> code_operlen = 1;
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77 cl -> addrmode = OPER_DIR;
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78 if ((v1 & 0xFFFF) > 0xff)
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79 errorp2(ERR_OVERFLOW);
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80 *b1 = (v1);
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81 return;
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82
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83 ins_gen_ext:
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84 *op = instab[cl -> opcode].ops[2];
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85 // cl -> code_operlen = 2;
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86 cl -> addrmode = OPER_EXT;
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87 *b1 = (v1 >> 8);
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88 *b2 = (v1 & 0xff);
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89 return;
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90 }
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91
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92 void insn_gen(asmstate_t *as, sourceline_t *cl, char **optr)
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93 {
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94 int rval;
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95 int v1;
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96 int b1, b2, b3, op;
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97
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98 if (**optr == '#')
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99 {
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100 // immediate mode has perterbations on instruction size
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101 (*optr)++;
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102 emitop(instab[cl -> opcode].ops[3]);
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103 rval = eval_expr(as, cl, optr, &v1);
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104
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105 switch (instab[cl -> opcode].instype)
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106 {
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107 case INSTYPE_GEN8:
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108 case INSTYPE_IMM8:
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109 cl -> addrmode = OPER_IMM8;
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110 // cl -> code_operlen = 1;
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111 emit(v1 & 0xff);
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112 if (v1 < -128 || v1 > 255)
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113 errorp2(ERR_OVERFLOW);
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114 return;
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115
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116 case INSTYPE_GEN:
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117 cl -> addrmode = OPER_IMM16;
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118 // cl -> code_operlen = 2;
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119 emit(v1 >> 8);
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120 emit(v1 & 0xff);
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121 return;
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122
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123 case INSTYPE_GEN32:
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124 cl -> addrmode = OPER_IMM32;
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125 // cl -> code_operlen = 4;
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126 emit(v1 >> 24);
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127 emit((v1 >> 16) & 0xff);
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128 emit((v1 >> 8) & 0xff);
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129 emit(v1 & 0xff);
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130 return;
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131
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132 default:
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133 errorp1(ERR_BADOPER);
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134 return;
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135
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136 }
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137
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138 return;
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139 }
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140 if (instab[cl -> opcode].instype == INSTYPE_IMM8)
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141 {
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142 errorp1(ERR_BADOPER);
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143 return;
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144 }
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145
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146 insn_gen_aux(as, cl, optr, &b1, &b2, &b3, &op);
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147 emitop(op);
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148 if (b1 != -1)
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149 emit(b1);
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150 if (b2 != -1)
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151 emit(b2);
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152 if (b3 != -1)
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153 emit(b3);
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154 }
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