DOS ain't dead

Datalight ROM-DOS floppy image creation (Emulation)

posted by ecm  , Düsseldorf, Germany, 08.12.2020, 16:29

I just added two options that help initialising the boot sector loader. Before this commit, _BOOTFILE had to point to a 512-bytes file complete with the BPB properly initialised already. If that is not the case, the new options _BOOTJUMPFILE and _BOOTCODEFILE allow specifying loader fragments to initialise, while the script will write the BPB itself. The jump file should be 3 or 11 bytes long, taken from the beginning of the loader file. The code file, for FAT12 or FAT16, should be 450 (or 448 or 446) bytes taken starting from offset 3Eh in the loader file. Here is an example, using dd. Your X could be used instead, too.

bootimg$ dd if=../ldosboot/boot12.bin bs=1 skip=$((0x3E)) of=code.bin
450+0 records in
450+0 records out
450 bytes copied, 0.00307256 s, 146 kB/s
bootimg$ dd if=../ldosboot/boot12.bin bs=1 skip=0 count=11 of=jump.bin
11+0 records in
11+0 records out
11 bytes copied, 0.000261832 s, 42.0 kB/s
bootimg$ nasm -I ../lmacros/ bootimg.asm -D_PAYLOADFILE=::empty -D_BOOTJUMPFILE="'jump.bin'" -D_BOOTCODEFILE="'code.bin'"
bootimg$

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l

Complete thread:

• Datalight ROM-DOS floppy image creation - rr, 02.02.2020, 16:44
  • Datalight ROM-DOS floppy image creation - Rugxulo, 04.02.2020, 05:07
    • Datalight ROM-DOS floppy image creation - rr, 05.02.2020, 15:59
      • FAT image creation - Rugxulo, 08.02.2020, 11:21
        • FAT image creation - marcov, 08.02.2020, 14:54
          • FAT image creation - Rugxulo, 16.02.2020, 18:36
            • FAT image creation - marcov, 17.02.2020, 10:21
              • FAT image creation - Rugxulo, 18.02.2020, 03:39
                • FAT image creation - Rugxulo, 18.02.2020, 21:13
                  • VBox vs. QEMU without VT-X - Rugxulo, 19.02.2020, 10:56
                    • cross-compilation versus emulated (native) compilation - Rugxulo, 04.03.2020, 03:07
                      • cross-compilation versus emulated (native) compilation - Rugxulo, 04.03.2020, 23:11
                • FAT image creation - marcov, 19.02.2020, 10:37
  • Datalight ROM-DOS floppy image creation - rr, 07.12.2020, 23:01
    • Datalight ROM-DOS floppy image creation - ecm, 08.12.2020, 14:06
    • Datalight ROM-DOS floppy image creation - ecm, 08.12.2020, 16:29
      • Datalight ROM-DOS floppy image creation - rr, 08.12.2020, 22:20
        • Datalight ROM-DOS floppy image creation - ecm, 09.12.2020, 10:49
    • Diskette image creation batch files - ecm, 15.12.2020, 22:38
      • Diskette image creation batch files - ecm, 15.12.2020, 22:58
        • Diskette image creation batch files - ecm, 19.12.2020, 18:21