Some rights reserved! Vintage technology preserved.
| Previous | Index | Next |
|---|
Recalling 198x: Boulder dash II had better levels, more challenging compared to the initial version. We usually select the 5th level, which is the strongest. However the PC version - with the same ugly CGA 2bit/pixel pinky palette - is above 32kB, so some tweaks were necessary in order to fit it in a 32kB option rom image. The conversion steps were:
- convert .EXE file to flat binary .COM file
- test it in DOSBox
- write a custom COM-packer that only needs a 64kB segment
- test it in DOSBox again :-)
- convert packed .COM file to a 32kB rom bios image
- waste cca. 6-8 hours in weekend to find that DS init is missing from your code
- fix it
- test it with qemu
Remark: loading segment is 2000h, could be lower and also some .EXE header fuzzing might allow to start it on machines with less than 512kB RAM.
Feel free to disassemble it p.ex. with nasm's ndisasm:
- rom image boulderII.rom
TO obtain a working FreeDOS .COM file, just extract it like this:
$ dd status=none if=boulderII.rom bs=1c skip=42 count=27482 of=BOULDER2.COM
| Previous | Index | Next |
|---|