Post by Tom Maneiro on Jul 24, 2004 11:10:19 GMT -5
i was doing some wacky experiments with some Genesis ROMs, and i managed to extract a Magical intro from a Doraemon game. While doing this, i've discovered that &H05 24-bit value can define ROM entrypoint (may be not new for some users there....), and i even added that intro in one of my demo games coded with BasiEgaXorz. Talking about this, i tried to add a custom program applying the same trick for get it working as an intro, and surprise! some programs crashes the ROM, and some others (like BasiEgaXorz programs) jumps to a location near from &H0200 (normal ROM entrypoint), before reaching main program code (i suppose that is the initialization stuff). I want to use something like this:
Yes, i am not an assembler guru, but at least know what does the instruction "jmp", and what it does. I made an small demo using these code, and it works, but when attaching it to a ROM, there's a point while demo jumps to &H0224 or something near (due it was hardcoded in the ROM). Is there a way to change ROM base address (at least in BasiEgaXorz) without wasting hours recoding bit by bit? For example to change from 0x0200 to something like 0xF000, and appplying this for the rest of ROM. I don't know how the Magical intros work, but if somebody are interested, i can post these intro here.
intro:
print "Hacked by Tom"
sleep 120
asm "jmp $0200"
Yes, i am not an assembler guru, but at least know what does the instruction "jmp", and what it does. I made an small demo using these code, and it works, but when attaching it to a ROM, there's a point while demo jumps to &H0224 or something near (due it was hardcoded in the ROM). Is there a way to change ROM base address (at least in BasiEgaXorz) without wasting hours recoding bit by bit? For example to change from 0x0200 to something like 0xF000, and appplying this for the rest of ROM. I don't know how the Magical intros work, but if somebody are interested, i can post these intro here.
