+uint32_t SymTypeAlcToAout(uint32_t alcType)
+{
+ uint32_t type = T_UNDF;
+
+ // Symbol type mappings here are derived from comparing Alcyon and BSD
+ // object files generated by MADMAC using the "size" utility from jag_utils
+ // (https://github.com/cubanismo/jag_utils) and the old PC/DOS Atari SDK.
+ //
+ // In BSD/a.out:
+ //
+ // 1) text | global text == text relocatable symbol in this file
+ // 2) data | global data == data relocatable symbol in this file
+ // 3) BSS | global BSS == bss relocatable symbol in this file
+ // 4) ABS | global ABS == non-relocatable symbol in this file
+ // 4) <none> | global <none> == undefined global symbol (extern)
+ //
+ // In DRI/Alcyon:
+ //
+ // 1) Everything seems to be marked defined.
+ // 2) There is an explicit "external" bit. It appears to be mutually
+ // exclusive with the "global" bit, at least in MADMAC's output.
+ // 3) There are separate "equated" and "equated reg" type bits that
+ // both represent ABS/non-relocatable values.
+ if ((alcType & ALCSYM_EQUATED) ||
+ (alcType & ALCSYM_EQUATED_REG))
+ type |= T_ABS;
+ else if (alcType & ALCSYM_TEXT)
+ type |= T_TEXT;
+ else if (alcType & ALCSYM_DATA)
+ type |= T_DATA;
+ else if (alcType & ALCSYM_BSS)
+ type |= T_BSS;
+
+ if ((alcType & ALCSYM_GLOBAL) ||
+ (alcType & ALCSYM_EXTERN))
+ type |= T_GLBL;
+
+ return type;
+}
+
+int LoadAlcyon(char * fname, int fd)
+{
+ char *ptr, *sptr, *aout, *saout, *traout, *strPtr;
+ char *trelptr, *drelptr, *relend;
+ struct ALCHEADER hdr;
+ struct ALCSYM *alcSyms;
+ long size = FileSize(fd);
+ size_t symStrLen;
+ size_t strOff;
+ uint32_t numSyms, numTRel, numDRel, i, j;
+
+ // Validate the file is at least large enough to contain a valid header
+ if (size < 0x1c)
+ {
+ printf("Alcyon object file %s too small to contain header\n", fname);
+ return 1;
+ }
+
+ // Allocate memory for file data
+ ptr = malloc(size);
+
+ if (ptr == NULL)
+ {
+ printf("Out of memory while processing %s\n", fname);
+ close(fd);
+ return 1;
+ }
+
+ // Read in file data
+ if (read(fd, ptr, size) != size)
+ {
+ printf("File read error on %s\n", fname);
+ close(fd);
+ free(ptr);
+ return 1;
+ }
+
+ close(fd);
+
+ hdr.magic = GetWord(ptr);
+ hdr.tsize = GetLong(ptr + 2);
+ hdr.dsize = GetLong(ptr + 6);
+ hdr.bsize = GetLong(ptr + 10);
+ hdr.ssize = GetLong(ptr + 14);
+
+ // Construct a BSD-style/aout object file in memory from the Alcyon data
+ numSyms = hdr.ssize / 14;
+
+ alcSyms = calloc(numSyms, sizeof(*alcSyms));
+ if (alcSyms == NULL)
+ {
+ printf("Out of memory while processing %s\n", fname);
+ free(ptr);
+ return 1;
+ }
+
+ sptr = ptr + 0x1c + hdr.tsize + hdr.dsize;
+ trelptr = sptr + hdr.ssize;
+ drelptr = trelptr + hdr.tsize;
+ relend = drelptr + hdr.dsize;
+
+ if (relend - ptr > size)
+ {
+ printf("Alcyon object file %s truncated: Header wants %ldB, file is %ldB\n",
+ fname, relend - ptr, size);
+ return 1;
+ }
+
+ for (i = 0, symStrLen = 0; i < numSyms; i++)
+ {
+ memcpy(alcSyms[i].name, sptr, 8);
+ alcSyms[i].type = GetWord(sptr + 8);
+ alcSyms[i].value = GetLong(sptr + 10);
+ symStrLen += strnlen((char *)alcSyms[i].name, 8) + 1;
+ sptr += 14;
+ }
+
+ for (i = 0, numTRel = 0; trelptr + i < drelptr; i += 2)
+ {
+ uint16_t rel = GetWord(trelptr + i);
+ if ((rel != ALCREL_ABS) &&
+ (rel != ALCREL_LONG))
+ numTRel++;
+ }
+
+ for (i = 0, numDRel = 0; drelptr + i < relend; i += 2)
+ {
+ uint16_t rel = GetWord(drelptr + i);
+ if ((rel != ALCREL_ABS) &&
+ (rel != ALCREL_LONG))
+ numDRel++;
+ }
+
+ aout = malloc(32 + /* header */
+ hdr.tsize +
+ hdr.dsize +
+ numTRel * 8 + /* Text section relocations */
+ numDRel * 8 + /* Data section relocations */
+ numSyms * 12 + /* symbol table */
+ 4 + symStrLen + /* string table size + strings */
+ 4 /* NULL-terminator for file */);
+ if (aout == NULL)
+ {
+ printf("Out of memory while processing %s\n", fname);
+ free(alcSyms);
+ free(ptr);
+ return 1;
+ }
+
+ // Construct the BSD/a.out header.
+ PutLong(aout, 0x00000107); // Magic number
+
+ PutLong(aout+4, hdr.tsize); // Text size
+ PutLong(aout+8, hdr.dsize); // Data size
+ PutLong(aout+12, hdr.bsize); // BSS size
+ PutLong(aout+16, numSyms * 12); // Symbol table size
+ PutLong(aout+20, 0L); // Entry point
+
+ PutLong(aout+24, numTRel * 8); // TEXT relocation size
+ PutLong(aout+28, numDRel * 8); // DATA relocation size
+
+ // Copy the raw text and data segments
+ memcpy(aout + 32, ptr + 0x1c, hdr.tsize);
+ memcpy(aout + 32 + hdr.tsize, ptr + 0x1c + hdr.tsize, hdr.dsize);
+
+ // Set traout to the start of the relocation tables
+ traout = aout + 32 + hdr.tsize + hdr.dsize;
+
+ // Set saout to symbol table location
+ saout = traout + numTRel * 8 + numDRel * 8 ;
+
+ // Convert the text and data relocations to a.out format
+ for (i = 0; trelptr + i < relend; i += 2)
+ {
+ uint16_t rel = GetWord(trelptr + i);
+ uint16_t relFlags = rel & 7;
+ uint32_t aoutflags = BSDREL_ABS;
+ uint32_t valoffset = 0;
+ char *const valaddr = aout + 32 + i;
+ const uint32_t reladdr = (trelptr + i >= drelptr) ? i - hdr.tsize : i;
+
+ if (relFlags == ALCREL_LONG)
+ {
+ i += 2;
+ rel = GetWord(trelptr + i);
+ relFlags = rel & 7;
+ }
+ else
+ {
+ aoutflags |= BSDREL_WORD;
+ }
+
+ if (relFlags == ALCREL_ABS)
+ continue;
+
+ switch (relFlags) {
+ case ALCREL_EXTPCREL:
+ aoutflags &= ~BSDREL_ABS;
+ aoutflags |= BSDREL_PCREL;
+ /* Fall through */
+ case ALCREL_EXTABS:
+ aoutflags |= BSDREL_GLOBAL;
+ aoutflags |= (ALCREL_SYMIDX(rel) << BSDREL_SYMIDX_SHIFT);
+ break;
+ case ALCREL_TEXT:
+ aoutflags |= BSDREL_SEG_TEXT;
+ break;
+ case ALCREL_DATA:
+ aoutflags |= BSDREL_SEG_DATA;
+ valoffset = hdr.tsize;
+ break;
+ case ALCREL_BSS:
+ aoutflags |= BSDREL_SEG_BSS;
+ valoffset = hdr.tsize + hdr.dsize;
+ break;
+
+ default:
+ printf("Invalid Alcyon relocation flags: 0x%02x\n", relFlags);
+ free(alcSyms);
+ free(ptr);
+ free(aout);
+ return 1;
+ }
+
+ if (valoffset != 0)
+ {
+ if (aoutflags & BSDREL_WORD)
+ {
+ valoffset += GetWord(valaddr);
+ PutWord(valaddr, (uint16_t)valoffset);
+ }
+ else
+ {
+ valoffset += GetLong(valaddr);
+ PutLong(valaddr, valoffset);
+ }
+ }
+
+ PutLong(traout, reladdr);
+ PutLong(traout+4, aoutflags);
+ traout += 8;
+ }
+
+ // Done with the Alcyon data.
+ free(ptr);
+ ptr = NULL;
+ sptr = NULL;
+
+ // Set strPtr to string table location and write string table size
+ strPtr = saout + numSyms * 12;
+ PutLong(strPtr, 4 + symStrLen);
+
+ for (i = 0, strOff = 4; i < numSyms; i++)
+ {
+ PutLong(saout, strOff); // String offset of symbol
+ PutLong(saout+4, SymTypeAlcToAout(alcSyms[i].type)); // Symbol type
+ PutLong(saout+8, alcSyms[i].value); // Symbol value
+ saout += 12;
+
+ for (j = 0; j < 8 && alcSyms[i].name[j] != '\0'; j++)
+ *(strPtr + strOff + j) = alcSyms[i].name[j];
+ strOff += j; // Step past string
+ *(strPtr + strOff) = '\0'; // Terminate symbol string
+ strOff++; // Step past termination
+ }
+
+ PutLong(strPtr + strOff, 0L); // Terminating long for object file
+
+ // Done with the Alcyon symbol table.
+ free(alcSyms);
+
+ // Now add this image to the list of pending ofiles (plist)
+ return AddToProcessingList(aout, fname, nullStr, 0, hdr.tsize, hdr.dsize, hdr.bsize);
+}
+
+//
+// What it says on the tin: check for a .o suffix on the passed in string
+//
+uint8_t HasDotOSuffix(char * s)
+{
+ char * temp = strrchr(s, '.');
+
+ if ((temp == NULL) || (strncmp(temp, ".o", 2) != 0))
+ return 0;
+
+ return 1;