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annotate src/insn_indexed.c @ 33:74a3fef7c8d0
Added general addressing modes (immediate, base page, extended, indexed)
| author | lost |
|---|---|
| date | Fri, 02 Jan 2009 05:02:47 +0000 |
| parents | 9bd0fbfe7405 |
| children | 538e15927776 |
| rev | line source |
|---|---|
| 32 | 1 /* |
| 2 insn_indexed.c | |
|
33
74a3fef7c8d0
Added general addressing modes (immediate, base page, extended, indexed)
lost
parents:
32
diff
changeset
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3 Copyright © 2009 William Astle |
| 32 | 4 |
| 5 This file is part of LWASM. | |
| 6 | |
| 7 LWASM is free software: you can redistribute it and/or modify it under the | |
| 8 terms of the GNU General Public License as published by the Free Software | |
| 9 Foundation, either version 3 of the License, or (at your option) any later | |
| 10 version. | |
| 11 | |
| 12 This program is distributed in the hope that it will be useful, but WITHOUT | |
| 13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 15 more details. | |
| 16 | |
| 17 You should have received a copy of the GNU General Public License along with | |
| 18 this program. If not, see <http://www.gnu.org/licenses/>. | |
| 19 */ | |
| 20 | |
| 21 /* | |
| 22 for handling indexed mode instructions | |
| 23 */ | |
| 24 | |
| 25 #define __insn_indexed_c_seen__ | |
| 26 | |
| 27 #include <ctype.h> | |
| 28 #include <string.h> | |
| 29 | |
| 30 #include "lwasm.h" | |
| 31 #include "instab.h" | |
| 32 #include "expr.h" | |
| 33 | |
| 34 void insn_indexed_aux(asmstate_t *as, lwasm_line_t *l, const char **p, int *b1, int *b2, int *b3) | |
| 35 { | |
| 36 static const char *regs = "X Y U S W PCRPC "; | |
| 37 static const struct { char *opstr; int pb; } simpleindex[] = | |
| 38 { | |
| 39 {",x", 0x84}, {",y", 0xa4}, {",u", 0xc4}, {",s", 0xe4}, | |
| 40 {",x+", 0x80}, {",y+", 0xa0}, {",u+", 0xc0}, {",s+", 0xe0}, | |
| 41 {",x++", 0x81}, {",y++", 0xa1}, {",u++", 0xc1}, {",s++", 0xe1}, | |
| 42 {",-x", 0x82}, {",-y", 0xa2}, {",-u", 0xc2}, {",-s", 0xe2}, | |
| 43 {",--x", 0x83}, {",--y", 0xa3}, {",--u", 0xc3}, {",--s", 0xe3}, | |
| 44 {"a,x", 0x86}, {"a,y", 0xa6}, {"a,u", 0xc6}, {"a,s", 0xe6}, | |
| 45 {"b,x", 0x85}, {"b,y", 0xa5}, {"b,u", 0xc5}, {"b,s", 0xe5}, | |
| 46 {"e,x", 0x87}, {"e,y", 0xa7}, {"e,u", 0xc7}, {"e,s", 0xe7}, | |
| 47 {"f,x", 0x8a}, {"f,y", 0xaa}, {"f,u", 0xca}, {"f,s", 0xea}, | |
| 48 {"d,x", 0x8b}, {"d,y", 0xab}, {"d,u", 0xcb}, {"d,s", 0xed}, | |
| 49 {"w,x", 0x8e}, {"w,y", 0xae}, {"w,u", 0xce}, {"w,s", 0xee}, | |
| 50 {",w", 0x8f}, {",w++", 0xcf}, {",--w", 0xef}, | |
| 51 | |
| 52 {"[,x]", 0x94}, {"[,y]", 0xb4}, {"[,u", 0xd4}, {"[,s]", 0xf4}, | |
| 53 {"[,x++]", 0x91}, {"[,y++]", 0xb1}, {"[,u++]", 0xd1}, {"[,s++]", 0xf1}, | |
| 54 {"[,--x]", 0x93}, {"[,--y]", 0xb3}, {"[,--u]", 0xd3}, {"[,--s]", 0xf3}, | |
| 55 {"[a,x]", 0x96}, {"[a,y]", 0xb6}, {"[a,u]", 0xd6}, {"[a,s]", 0xf6}, | |
| 56 {"[b,x]", 0x95}, {"[b,y]", 0xb5}, {"[b,u]", 0xd5}, {"[b,s]", 0xf5}, | |
| 57 {"[e,x]", 0x97}, {"[e,y]", 0xb7}, {"[e,u]", 0xd7}, {"[e,s]", 0xf7}, | |
| 58 {"[f,x]", 0x9a}, {"[f,y]", 0xba}, {"[f,u]", 0xda}, {"[f,s]", 0xfa}, | |
| 59 {"[d,x]", 0x9b}, {"[d,y]", 0xbb}, {"[d,u]", 0xdb}, {"[d,s]", 0xfd}, | |
| 60 {"[w,x]", 0x9e}, {"[w,y]", 0xbe}, {"[w,u]", 0xde}, {"[w,s]", 0xfe}, | |
| 61 {"[,w]", 0x90}, {"[,w++]", 0xd0}, {"[,--w]", 0xf0}, | |
| 62 | |
| 63 { "", -1 } | |
| 64 }; | |
| 65 char stbuf[25]; | |
| 66 int i; | |
| 67 int f8 = 0, f16 = 0; | |
| 68 int rn; | |
| 69 int indir = 0; | |
| 70 int rval; | |
| 71 int f0 = 0; | |
| 72 const char *p2; | |
| 73 lwasm_expr_stack_t *s; | |
| 74 | |
| 75 *b1 = *b2 = *b3 = -1; | |
| 76 | |
| 77 for (i = 0; i < 24; i++) | |
| 78 { | |
| 79 if (*((*p) + i) && !isspace(*((*p) + i))) | |
| 80 stbuf[i] = *((*p) + i); | |
| 81 else | |
| 82 break; | |
| 83 } | |
| 84 stbuf[i] = '\0'; | |
| 85 if (!*((*p) + i) || isspace(*((*p) + i))) | |
| 86 { | |
| 87 int j; | |
| 88 // do simple lookup | |
| 89 for (j = 0; simpleindex[j].opstr[0]; j++) | |
| 90 { | |
| 91 if (!strcasecmp(stbuf, simpleindex[j].opstr)) | |
| 92 break; | |
| 93 } | |
| 94 if (simpleindex[j].opstr[0]) | |
| 95 { | |
| 96 *b1 = simpleindex[j].pb; | |
| 97 (*p) += i; | |
| 98 return; | |
| 99 } | |
| 100 } | |
| 101 | |
| 102 // now we have the hard ones to work out here | |
| 103 | |
| 104 // if we've previously forced the sizes, make a note of it | |
| 105 if (l -> fsize == 1) | |
| 106 f8 = 1; | |
| 107 else if (l -> fsize == 2) | |
| 108 f16 = 1; | |
| 109 | |
| 110 if (**p == '[') | |
| 111 { | |
| 112 indir = 1; | |
| 113 (*p)++; | |
| 114 } | |
| 115 | |
| 116 rn = 0; | |
| 117 for (i = 0; (*p)[i] && !isspace((*p)[i]); i++) | |
| 118 { | |
| 119 if ((*p)[i] == ',') | |
| 120 { | |
| 121 rn = 1; | |
| 122 break; | |
| 123 } | |
| 124 } | |
| 125 | |
| 126 if (!rn && indir) | |
| 127 { | |
| 128 // extended indir | |
| 129 *b1 = 0x9f; | |
| 130 *b2 = 0; | |
| 131 *b3 = 0; | |
| 132 s = lwasm_expr_eval(*p, &p2); | |
| 133 if (!s) | |
| 134 { | |
| 135 register_error(as, l, 1, "Bad expression"); | |
| 136 return; | |
| 137 } | |
| 138 *p = p2; | |
| 139 if (**p != ']') | |
| 140 { | |
| 141 register_error(as, l, 1, "Bad operand"); | |
| 142 return; | |
| 143 } | |
| 144 (*p)++; | |
| 145 if (!lwasm_expr_is_constant(s)) | |
| 146 { | |
| 147 register_error(as, l, 2, "Incomplete reference"); | |
| 148 } | |
| 149 rn = lwasm_expr_get_value(s); | |
| 150 lwasm_expr_stack_free(s); | |
| 151 *b2 = (rn >> 8) & 0xff; | |
| 152 *b3 = rn & 0xff; | |
| 153 return; | |
| 154 } | |
| 155 | |
| 156 if (**p == '<') | |
| 157 { | |
| 158 f8 = 1; | |
| 159 (*p)++; | |
| 160 } | |
| 161 else if (**p == '>') | |
| 162 { | |
| 163 f16 = 1; | |
| 164 (*p)++; | |
| 165 } | |
| 166 | |
| 167 if (**p == '0' && *(*p+1) == ',') | |
| 168 { | |
| 169 f0 = 1; | |
| 170 } | |
| 171 | |
| 172 // now we have to evaluate the expression | |
| 173 s = lwasm_expr_eval(*p, &p2); | |
| 174 *p = p2; | |
| 175 if (!s) | |
| 176 { | |
| 177 register_error(as, l, 1, "Bad expression"); | |
| 178 return; | |
| 179 } | |
| 180 if (!lwasm_expr_is_constant(s)) | |
| 181 { | |
| 182 register_error(as, l, 2, "Incomplete reference"); | |
| 183 if (!f8 && !f0) | |
| 184 { | |
| 185 f16 = 1; | |
| 186 l -> fsize = 2; | |
| 187 } | |
| 188 } | |
| 189 rval = lwasm_expr_get_value(s); | |
| 190 lwasm_expr_stack_free(s); | |
| 191 | |
| 192 // now look for a comma; if not present, explode | |
| 193 if (*(*p)++ != ',') | |
| 194 { | |
| 195 // syntax error; force 0 bit | |
| 196 *b1 = 00; | |
| 197 return; | |
| 198 } | |
| 199 | |
| 200 // now get the register | |
| 201 rn = lwasm_lookupreg3(regs, p); | |
| 202 if (rn < 0) | |
| 203 goto reterr; | |
| 204 | |
| 205 if (indir) | |
| 206 { | |
| 207 if (**p != ']') | |
| 208 goto reterr; | |
| 209 else | |
| 210 (*p)++; | |
| 211 } | |
| 212 | |
| 213 // nnnn,W is only 16 bit | |
| 214 if (rn == 4) | |
| 215 { | |
| 216 if (f8) | |
| 217 goto reterr; | |
| 218 if (!f16 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE) && rval == 0) | |
| 219 { | |
| 220 if (indir) | |
| 221 *b1 = 0x90; | |
| 222 else | |
| 223 *b1 = 0x8f; | |
| 224 return; | |
| 225 } | |
| 226 if (indir) | |
| 227 *b1 = 0xb0; | |
| 228 else | |
| 229 *b1 = 0xcf; | |
| 230 *b2 = (rval >> 8) & 0xff; | |
| 231 *b3 = rval & 0xff; | |
| 232 return; | |
| 233 } | |
| 234 | |
| 235 if (indir) indir = 0x10; | |
| 236 | |
| 237 // PCR? redo v1, v2 relative to current address | |
| 238 if (rn == 5) | |
| 239 { | |
| 240 rval -= as -> addr; | |
| 241 | |
| 242 // we have a slight problem here | |
| 243 // PCR based on current insn loc is really | |
| 244 // -125 <= offset <= +130 (8 bit offset) | |
| 245 // NOTE: when we are called, we already have the opcode emitted | |
| 246 // so we only need to worry about the size of the operand | |
| 247 // hence the 2 and 3 magic numbers below instead of 3 and 4 | |
| 248 // (and that also avoids errors with two byte opcodes, etc) | |
| 249 if (f8 || (!f16 && rval >= -125 && rval <= 130)) | |
| 250 { | |
| 251 *b1 = indir | 0x8C; | |
| 252 rval -= 2; | |
| 253 if (rval < -128 || rval > 127) | |
| 254 register_error(as, l, 2, "Byte overflow"); | |
| 255 *b2 = rval & 0xff; | |
| 256 return; | |
| 257 } | |
| 258 | |
| 259 // anything else is 16 bit offset | |
| 260 // need 16 bit | |
| 261 *b1 = indir | 0x8D; | |
| 262 rval -= 3; | |
| 263 *b2 = (rval >> 8) & 0xff; | |
| 264 *b3 = rval & 0xff; | |
| 265 return; | |
| 266 } | |
| 267 | |
| 268 // constant offset from PC | |
| 269 if (rn == 6) | |
| 270 { | |
| 271 if (f8 || (!f16 && rval >= -128 && rval <= 127)) | |
| 272 { | |
| 273 *b1 = indir | 0x8C; | |
| 274 if (rval < -128 || rval > 127) | |
| 275 register_error(as, l, 2, "Byte overflow"); | |
| 276 *b2 = rval & 0xff; | |
| 277 return; | |
| 278 } | |
| 279 | |
| 280 // everything else must be 16 bit | |
| 281 // need 16 bit | |
| 282 *b1 = indir | 0x8D; | |
| 283 *b2 = (rval >> 8) & 0xff; | |
| 284 *b3 = rval & 0xff; | |
| 285 return; | |
| 286 } | |
| 287 | |
| 288 // we only have to deal with x,y,u,s here | |
| 289 if (!f8 && !f16 && rval >= -16 && rval <= 15) | |
| 290 { | |
| 291 if (rval == 0 && !f0 && !(as -> pragmas & PRAGMA_NOINDEX0TONONE)) | |
| 292 { | |
| 293 *b1 = rn << 5 | indir | 0x80 | 0x04; | |
| 294 return; | |
| 295 } | |
| 296 // we pick the smallest value here | |
| 297 if (indir) | |
| 298 { | |
| 299 f8 = 1; | |
| 300 goto no5bit; | |
| 301 } | |
| 302 *b1 = rn << 5 | (rval & 0x1F); | |
| 303 return; | |
| 304 } | |
| 305 no5bit: | |
| 306 if (f16 || (!f8 && (rval < -128 || rval > 127))) | |
| 307 { | |
| 308 // must be a 16 bit offset here | |
| 309 *b1 = rn << 5 | indir | 0x80 | 0x09; | |
| 310 *b2 = (rval >> 8) & 0xff; | |
| 311 *b3 = rval & 0xff; | |
| 312 return; | |
| 313 } | |
| 314 | |
| 315 // if we're here, we have an 8 bit offset | |
| 316 *b1 = rn << 5 | indir | 0x80 | 0x08; | |
| 317 if (rval < -128 || rval > 127) | |
| 318 register_error(as, l, 2, "Byte overflow"); | |
| 319 *b2 = rval & 0xff; | |
| 320 return; | |
| 321 reterr: | |
| 322 *b1 = 0; | |
| 323 return; | |
| 324 } | |
| 325 | |
| 326 OPFUNC(insn_indexed) | |
| 327 { | |
| 328 int b1, b2, b3; | |
| 329 | |
| 330 lwasm_emitop(as, l, instab[opnum].ops[0]); | |
| 331 | |
| 332 insn_indexed_aux(as, l, (const char **)p, &b1, &b2, &b3); | |
| 333 if (b1 != -1) | |
| 334 lwasm_emit(as, l, b1); | |
| 335 if (b2 != -1) | |
| 336 lwasm_emit(as, l, b2); | |
| 337 if (b3 != -1) | |
| 338 lwasm_emit(as, l, b3); | |
| 339 } |