Mercurial > hg-old > index.cgi
annotate src/output.c @ 87:41ff4686b46b
Checkpoint: object format output
| author | lost |
|---|---|
| date | Sat, 17 Jan 2009 02:59:24 +0000 |
| parents | 033a328a10ae |
| children | 6460a1fb5f1f |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 output.c |
| 46 | 3 Copyright © 2009 William Astle |
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4 |
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5 This file is part of LWASM. |
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6 |
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7 LWASM is free software: you can redistribute it and/or modify it under the |
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8 terms of the GNU General Public License as published by the Free Software |
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9 Foundation, either version 3 of the License, or (at your option) any later |
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10 version. |
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11 |
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12 This program is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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15 more details. |
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16 |
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17 You should have received a copy of the GNU General Public License along with |
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18 this program. If not, see <http://www.gnu.org/licenses/>. |
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19 |
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20 |
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21 Contains the code for actually outputting the assembled code |
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22 */ |
| 0 | 23 |
| 24 //#include <ctype.h> | |
| 25 #include <errno.h> | |
| 26 #include <stdio.h> | |
| 27 //#include <stdlib.h> | |
| 28 #include <string.h> | |
| 29 #include <unistd.h> | |
| 30 #define __output_c_seen__ | |
| 31 //#include "instab.h" | |
| 32 #include "lwasm.h" | |
| 85 | 33 #include "util.h" |
| 0 | 34 |
| 35 void write_code_raw(asmstate_t *as, FILE *of); | |
| 36 void write_code_decb(asmstate_t *as, FILE *of); | |
| 37 void write_code_rawrel(asmstate_t *as, FILE *of); | |
| 85 | 38 void write_code_obj(asmstate_t *as, FILE *of); |
| 0 | 39 |
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40 // this prevents warnings about not using the return value of fwrite() |
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41 #define writebytes(s, l, c, f) do { int r; r = fwrite((s), (l), (c), (f)); } while (0) |
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42 |
| 46 | 43 void lwasm_output(asmstate_t *as) |
| 0 | 44 { |
| 45 FILE *of; | |
| 46 | |
| 47 if (as -> errorcount > 0) | |
| 48 { | |
| 49 fprintf(stderr, "Not doing output due to assembly errors.\n"); | |
| 50 return; | |
| 51 } | |
| 52 | |
| 53 of = fopen(as -> outfile, "wb"); | |
| 54 if (!of) | |
| 55 { | |
| 56 fprintf(stderr, "Cannot open '%s' for output", as -> outfile); | |
| 57 perror(""); | |
| 58 return; | |
| 59 } | |
| 60 | |
| 61 switch (as -> outformat) | |
| 62 { | |
| 63 case OUTPUT_RAW: | |
| 64 write_code_raw(as, of); | |
| 65 break; | |
| 66 | |
| 67 case OUTPUT_DECB: | |
| 68 write_code_decb(as, of); | |
| 69 break; | |
| 70 | |
| 71 case OUTPUT_RAWREL: | |
| 72 write_code_rawrel(as, of); | |
| 73 break; | |
| 85 | 74 |
| 75 case OUTPUT_OBJ: | |
| 76 write_code_obj(as, of); | |
| 77 break; | |
| 78 | |
| 0 | 79 default: |
| 80 fprintf(stderr, "BUG: unrecognized output format when generating output file\n"); | |
| 81 fclose(of); | |
| 82 unlink(as -> outfile); | |
| 83 return; | |
| 84 } | |
| 85 | |
| 86 fclose(of); | |
| 87 } | |
| 88 | |
| 89 /* | |
| 90 rawrel output treats an ORG directive as an offset from the start of the | |
| 91 file. Undefined results will occur if an ORG directive moves the output | |
| 92 pointer backward. This particular implementation uses "fseek" to handle | |
| 93 ORG requests and to skip over RMBs. | |
| 94 | |
| 95 This simple brain damanged method simply does an fseek before outputting | |
| 96 each instruction. | |
| 97 */ | |
| 98 void write_code_rawrel(asmstate_t *as, FILE *of) | |
| 99 { | |
| 46 | 100 lwasm_line_t *cl; |
| 0 | 101 |
| 46 | 102 for (cl = as -> lineshead; cl; cl = cl -> next) |
| 0 | 103 { |
| 46 | 104 if (cl -> codelen == 0) |
| 0 | 105 continue; |
| 106 | |
| 46 | 107 fseek(of, cl -> codeaddr, SEEK_SET); |
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108 writebytes(cl -> bytes, cl -> codelen, 1, of); |
| 0 | 109 } |
| 110 } | |
| 111 | |
| 112 /* | |
| 113 raw merely writes all the bytes directly to the file as is. ORG is just a | |
| 114 reference for the assembler to handle absolute references. Multiple ORG | |
| 115 statements will produce mostly useless results | |
| 116 */ | |
| 117 void write_code_raw(asmstate_t *as, FILE *of) | |
| 118 { | |
| 46 | 119 lwasm_line_t *cl; |
| 0 | 120 |
| 46 | 121 for (cl = as -> lineshead; cl; cl = cl -> next) |
| 0 | 122 { |
| 46 | 123 if (cl -> nocodelen) |
| 0 | 124 { |
| 125 int i; | |
| 46 | 126 for (i = 0; i < cl -> nocodelen; i++) |
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127 writebytes("\0", 1, 1, of); |
| 0 | 128 continue; |
| 129 } | |
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130 writebytes(cl -> bytes, cl -> codelen, 1, of); |
| 0 | 131 } |
| 132 } | |
| 133 | |
| 134 void write_code_decb(asmstate_t *as, FILE *of) | |
| 135 { | |
| 136 long preambloc; | |
| 46 | 137 lwasm_line_t *cl; |
| 0 | 138 int blocklen = -1; |
| 139 int nextcalc = -1; | |
| 140 unsigned char outbuf[5]; | |
| 141 | |
| 46 | 142 for (cl = as -> lineshead; cl; cl = cl -> next) |
| 0 | 143 { |
| 46 | 144 if (cl -> nocodelen) |
| 0 | 145 continue; |
| 46 | 146 if (cl -> codeaddr != nextcalc && cl -> codelen > 0) |
| 0 | 147 { |
| 148 // need preamble here | |
| 149 if (blocklen > 0) | |
| 150 { | |
| 46 | 151 // update previous preamble if needed |
| 0 | 152 fseek(of, preambloc, SEEK_SET); |
| 153 outbuf[0] = (blocklen >> 8) & 0xFF; | |
| 154 outbuf[1] = blocklen & 0xFF; | |
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155 writebytes(outbuf, 2, 1, of); |
| 0 | 156 fseek(of, 0, SEEK_END); |
| 157 } | |
| 158 blocklen = 0; | |
| 46 | 159 nextcalc = cl -> codeaddr; |
| 0 | 160 outbuf[0] = 0x00; |
| 161 outbuf[1] = 0x00; | |
| 162 outbuf[2] = 0x00; | |
| 163 outbuf[3] = (nextcalc >> 8) & 0xFF; | |
| 164 outbuf[4] = nextcalc & 0xFF; | |
| 165 preambloc = ftell(of) + 1; | |
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166 writebytes(outbuf, 5, 1, of); |
| 0 | 167 } |
| 46 | 168 nextcalc += cl -> codelen; |
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169 writebytes(cl -> bytes, cl -> codelen, 1, of); |
| 46 | 170 blocklen += cl -> codelen; |
| 0 | 171 } |
| 172 if (blocklen > 0) | |
| 173 { | |
| 174 fseek(of, preambloc, SEEK_SET); | |
| 175 outbuf[0] = (blocklen >> 8) & 0xFF; | |
| 176 outbuf[1] = blocklen & 0xFF; | |
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177 writebytes(outbuf, 2, 1, of); |
| 0 | 178 fseek(of, 0, SEEK_END); |
| 179 } | |
| 180 | |
| 181 // now write postamble | |
| 182 outbuf[0] = 0xFF; | |
| 183 outbuf[1] = 0x00; | |
| 184 outbuf[2] = 0x00; | |
| 185 outbuf[3] = (as -> execaddr >> 8) & 0xFF; | |
| 186 outbuf[4] = (as -> execaddr) & 0xFF; | |
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187 writebytes(outbuf, 5, 1, of); |
| 0 | 188 } |
| 85 | 189 |
| 190 void write_code_obj_sbadd(sectiontab_t *s, unsigned char b) | |
| 191 { | |
| 192 if (s -> oblen >= s -> obsize) | |
| 193 { | |
| 194 s -> obytes = lwasm_realloc(s -> obytes, s -> obsize + 128); | |
| 195 s -> obsize += 128; | |
| 196 } | |
| 197 s -> obytes[s -> oblen] = b; | |
| 198 s -> oblen += 1; | |
| 199 } | |
| 200 | |
| 201 void write_code_obj(asmstate_t *as, FILE *of) | |
| 202 { | |
| 203 lwasm_line_t *l; | |
| 87 | 204 sectiontab_t *s; |
| 85 | 205 int i; |
| 87 | 206 unsigned char buf[16]; |
| 85 | 207 |
| 208 // output the magic number and file header | |
| 87 | 209 // the 8 is NOT an error |
| 210 writebytes("LWOBJ16", 8, 1, of); | |
| 85 | 211 |
| 212 // run through the entire system and build the byte streams for each | |
| 213 // section; at the same time, generate a list of "local" symbols to | |
| 214 // output for each section | |
| 215 // NOTE: for "local" symbols, we will append \x01 and the ascii string | |
| 216 // of the context identifier (so sym in context 1 would be "sym\x011" | |
| 217 // we can do this because the linker can handle symbols with any | |
| 218 // character other than NUL. | |
| 219 // also we will generate a list of incomplete references for each | |
| 220 // section along with the actual definition that will be output | |
| 221 | |
| 222 // once all this information is generated, we will output each section | |
| 223 // to the file | |
| 224 | |
| 225 // NOTE: we build everything in memory then output it because the | |
| 226 // assembler accepts multiple instances of the same section but the | |
| 227 // linker expects only one instance of each section in the object file | |
| 228 // so we need to collect all the various pieces of a section together | |
| 229 // (also, the assembler treated multiple instances of the same section | |
| 230 // as continuations of previous sections so we would need to collect | |
| 231 // them together anyway. | |
| 232 | |
| 233 for (l = as -> lineshead; l; l = l -> next) | |
| 234 { | |
| 235 if (l -> sect) | |
| 236 { | |
| 237 // we're in a section - need to output some bytes | |
| 238 for (i = 0; i < l -> codelen; i++) | |
| 239 write_code_obj_sbadd(l -> sect, l -> bytes[i]); | |
| 240 for (i = 0; i < l -> nocodelen; i++) | |
| 241 write_code_obj_sbadd(l -> sect, 0); | |
| 242 | |
| 243 // do we have a "relocation"? If so, add a reference to the | |
| 244 // relocation table | |
| 245 if (l -> relocoff >= 0) | |
| 246 { | |
| 86 | 247 section_reloc_list_t *re; |
| 248 | |
| 249 // build the relocation reference for the linker | |
| 250 re = lwasm_alloc(sizeof(section_reloc_list_t)); | |
| 251 re -> next = l -> sect -> rl; | |
| 252 l -> sect -> rl = re; | |
| 253 | |
| 254 re -> offset = l -> codeaddr + l -> relocoff; | |
| 255 re -> expr = l -> exprs[0]; | |
| 85 | 256 } |
| 257 } | |
| 258 } | |
| 87 | 259 |
| 260 // run through the sections | |
| 261 for (s = as -> sections; s; s = s -> next) | |
| 262 { | |
| 263 // write the name | |
| 264 writebytes(s -> name, strlen(s -> name) + 1, 1, of); | |
| 265 | |
| 266 // write the flags | |
| 267 if (s -> flags & SECTION_BSS) | |
| 268 writebytes("\x01", 1, 1, of); | |
| 269 | |
| 270 // indicate end of flags - the "" is NOT an error | |
| 271 writebytes("", 1, 1, of); | |
| 272 | |
| 273 | |
| 274 // now blast out the code | |
| 275 | |
| 276 // length | |
| 277 buf[0] = s -> oblen >> 8 & 0xff; | |
| 278 buf[1] = s -> oblen & 0xff; | |
| 279 writebytes(buf, 2, 1, of); | |
| 280 | |
| 281 if (!(s -> flags & SECTION_BSS)) | |
| 282 { | |
| 283 writebytes(s -> obytes, s -> oblen, 1, of); | |
| 284 } | |
| 285 } | |
| 286 | |
| 287 // flag no more sections | |
| 288 // the "" is NOT an error | |
| 289 writebytes("", 1, 1, of); | |
| 85 | 290 } |