[SMD]How to hack Gens to use 2megabytes as RAM?? (or: how NOT to hack)

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Main - Display Case - [SMD]How to hack Gens to use 2megabytes as RAM?? (or: how NOT to hack)

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TI_

Posted on 10-13-09 09:15 PM

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Somebody knows how to increase RAM for SMD?
to use all 0xE00000 - 0xFFFFFF for read/write .

We tried to change:

Mem_M68k.h

extern unsigned char Ram_68k[2 * 1024 * 1024];

Mem_M68k.asm

DECL Ram_68k
resb 2 * 1024 * 1024

ALIGN32

M68K_Read_Byte_Ram0:
and ebx, 0x7FFFF
xor ebx, 1
mov al, [Ram_68k + ebx]
pop ebx
ret

ALIGN32

M68K_Read_Byte_Ram1:
and ebx, 0x7FFFF
xor ebx, 0x80001
mov al, [Ram_68k + ebx]
pop ebx
ret

e.t.c.

M68K_Write_Word_Ram1:
and ebx, 0x7FFFF
mov [Ram_68k + ebx + 0x100000], ax
; pop ecx
; pop ebx
ret

it doesn't help.
test:

10:0074 23 FC MOVE.L #$12345678,($00F10002)
10:007E 0C B9 CMPI.L #$12345678,($00F10002) ; - ok
10:0088 66 00 BNE #$0012 [10:009C]
10:008C 0C B9 CMPI.L #$12345678,($00FF0002) ; F10002=FF0002
10:0096 66 00 BNE #$0004 [10:009C]
10:009A 4E 75 RTS

as result , FFxxxx=F0xxxx=F1xxxx=F2xxxx и т.д.

Kiokuffiib11

Posted on 10-14-09 03:00 AM

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Wish I could help. Couldn't using something like Hexecute to expand the rom, then having it jump to a specific spot work?

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TI_

Posted on 10-14-09 12:29 PM

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Posted by Kiokuffiib11
Wish I could help. Couldn't using something like Hexecute to expand the rom, then having it jump to a specific spot work?

expand the rom? for what ? I ask how to increase RAM, not ROM.

It's easy to change Gens memmap to make support up to 13mb roms (such as Kabal umk hack)

Mem_M68k.h
extern unsigned char Rom_Data[13 * 1024 * 1024];

Mem_M68k.asm

replace
dd M68K_Read_Byte_Bad, ; 0x800000 - 0x87FFFF
with
dd M68K_Read_Byte_RomG, ; 0x800000 - 0x87FFFF
and all other _bad

also:
DECL Rom_Data
resb 13 * 1024 * 1024

create same for all letters:
ALIGN32

M68K_Read_Byte_RomG:
and ebx, 0x7FFFF
xor ebx, 0x800001
mov al, [Rom_Data + ebx]
pop ebx
ret

and now after compile, emulator support 13megabytes ROMS.

but same changes won't work for RAM:

dd M68K_Read_Byte_Ram, ; 0xE00000 - 0xE7FFFF
dd M68K_Read_Byte_Ram, ; 0xE80000 - 0xEFFFFF

ALIGN32

M68K_Read_Byte_Ram:
and ebx, 0xFFFF ; reduce to 65536kb
xor ebx, 1
mov al, [Ram_68k + ebx]
pop ebx
ret

change to 0x7FFFF + in all other places ( 512kb segment, same as for ROM) , but nothing happens. new areas, works as old (as you see in test)

TI_

Posted on 12-27-09 02:21 PM (rev. 3 of 05-11-11 03:24 PM)

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GENS 100Mhz CPU +2 MB RAM. (based on gensmovie11a)
(adress space $E00000=>$FFFFFF )
+ROm support up to 13Megabytes.

Ti's homepage

Parasyte

Posted on 12-27-09 05:41 PM

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I'm sorry, but, this is a horrible idea. If you can't program/hack around the inherent system limitations, give up! Don't go "fixing" it by emulating hardware that didn't exist. And for that matter, don't go "fixing" it by creating new hardware just so it can be emulated.

*sigh*

TI_

Posted on 12-27-09 08:57 PM

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Posted by Parasyte
I'm sorry, but, this is a horrible idea. If you can't program/hack around the inherent system limitations, give up! Don't go "fixing" it by emulating hardware that didn't exist. And for that matter, don't go "fixing" it by creating new hardware just so it can be emulated.
*sigh*

actually this 'hack' was requested for dune. Segaman created dune map/mission editor , and some of my friends wanted to create own maps with more than 72buildings(limit for dune) and more units limit to make very intersting and hard missions...

Parasyte

Posted on 12-27-09 09:13 PM

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There was a similar project called "Ultimate Mortal Kombat Trilogy" which also requires a customized emulator to play. Once it gets to that point, you might consider writing a modern game, instead of hacking one for old hardware that can't faithfully reproduce your vision.

TI_

Posted on 12-27-09 10:31 PM

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Posted by Parasyte
There was a similar project called "Ultimate Mortal Kombat Trilogy" which also requires a customized emulator to play. Once it gets to that point, you might consider writing a modern game, instead of hacking one for old hardware that can't faithfully reproduce your vision.

many peoples that I know want to see smd-dune port on PC , but no one can do it.
romhacking is much more easy , than write new game.

DahrkDaiz

Posted on 12-28-09 01:48 PM

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lol lies

Parasyte

Posted on 12-29-09 04:19 AM

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ROM hacking is quite a bit more difficult. For the very reason you've added more RAM and a higher clock rate to an emulator.

TI_

Posted on 05-11-11 03:20 PM (rev. 2 of 05-11-11 03:22 PM)

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del

GreyMaria

Posted on 05-11-11 06:27 PM (rev. 2 of 05-11-11 06:30 PM)

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This thread is pure gold-plated silver.

Frickin' amazing.

Can I get some red museum ropes over here? A brass sign reading "How NOT to Hack"? An audio playback device for a live-action reenactment of the events contained within?

Maybe a little bit of gray spraypaint, too? Or a padlock and a wrist-slapper? Because that is a beautiful one-and-a-half-year bump.

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Kawa

Posted on 05-11-11 06:29 PM

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I can get you a Display Case, but not the rest. Is that okay?

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Main - Display Case - [SMD]How to hack Gens to use 2megabytes as RAM?? (or: how NOT to hack)

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