mirror of https://github.com/aufflick/kegs.git
124 lines
5.5 KiB
Plaintext
124 lines
5.5 KiB
Plaintext
# $Id: README.a2.compatibility,v 1.2 2004/10/18 18:17:21 kentd Exp $
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Flobynoid: Must disable Fast Disk Emul (hit F7 to toggle it off) since
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game's loader relies on the sector order on the disk (reads 8
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sectors from the start without checking headers, assumes every other
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physical sector is skipped due to decode delays).
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Bard's Tale II GS: Doesn't recognize any save disk as a ProDOS disk.
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It's detecting a "ProDOS" disk by checking for a string on block
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0 at offset 0x15e. GSOS on system 6 has moved the string to 0x162,
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so disks inited under GSOS will be detected as "Not a PRODOS disk".
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Just make a copy of the Bard's Tale disk image to another file and
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then mount that new image and remove all the files using the Finder.
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Then rename the volume and you have a working save disk.
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Robotron 2084:
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Robot Battle:
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These cracks use a "Fastloader" which is buggy.
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It tries to JMP $F3D4 and expects to hit an RTS soon.
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But on a IIgs it will access some illegal memory causing a code
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yellow. You can just ignore the code yellow.
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Beyond Castle Wolfenstein: Make sure your disk is writeable (not compressed!)
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Breakout: Has trouble loading from the cracked copy.
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From the BASIC prompt, do: "CALL -151" then "C083 N C083" then
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"BLOAD INTBASIC" then run breakout. Then it runs fine.
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Burgertime: This is a bad crack. Loader starts the game by writing
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the game entry point into $0036/$0037, and then executing a BRK
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instruction. The BRK handler on an old Apple II will try to write
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out a message by calling through $0036/$0037, and this will start
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the game. But on a IIgs, the ROM sets the $0036/$0037 vectors
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back to the default, and so we crash into the monitor instead.
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Here's a memory fix and a disk-image fix: From the crack screen,
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press Shift-F6 (or middle mouse button) and in the KEGS debugger
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window enter: "1d0a:ea 6c 36 0" and then "g". You can make
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this fix to the disk image using a sector editor and change
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Track $1E sector $09 offset $0A from "60 78 A9 03" to "EA 6C 36 00"
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and write it back.
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Caverns of Callisto: Requires old C600 ROM in slot 6 (Slot 6==Your Card).
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Championship Loderunner: Requires disk to be writeable or else it starts
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the level and then jumps immediately back to the title page.
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Jeopardy: Disk must be writeable or else it displays "DISK ERROR" and
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then crashes into the monitor.
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Drol: Needs slot 6 set to "Your Card" from the IIgs control panel
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(Ctrl-Cmd-ESC, then choose "Slots").
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I found Drol hard, so here are some cheats. First, the standard cheat
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for Drol is to have infinite lives, this cheat is to edit the disk
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image:
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Track $0B, Sector $0A, byte $22 to EA EA
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Track $11, Sector $0A, byte $10 to EA EA
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Track $17, Sector $09, byte $B2 to EA EA
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I didn't create those cheats, I got it from textfiles.com.
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My cheats are for the monsters to never kill you--just run right
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through them.
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While playing Drol, press Shift-F6 (or middle mouse button) to
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enter the KEGS debugger, and then:
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0/f28:18 18 # Monsters' missiles won't kill you
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0/e05:90 0c # Monsters won't kill you
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Continue emulation by type "g" and then enter.
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Other things, like the bird, axes, swords still kill you.
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To easily solve the third screen, move your man to the far right
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side on the top level, so that you are directly above the woman
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on the bottom row. Fly into the air "A" and then get to the KEGS
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debugger, and type:
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0/c:4
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and then continue with "g". Now press "Z" and you will go all
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the way down and land on the woman and end the level. It's
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useful to have made the two above patches so that touching monsters
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won't kill you.
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Two more patches that only apply to level 3, and so most be made
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in memory each time you enter level 3:
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6cf3:18 18 18 # Axes won't kill you
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6f70:38 38 # Swords/arrows won't kill you
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The bird and the guy you can't kill will still kill you. These
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cheats were enough to make the game easily playable.
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In the game, your death is indicated by setting location $001E to
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$FF. Setting breakpoints there can let you find other cheats.
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Moon Patrol: Crashes into the monitor after completing checkpoint E.
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To fix the Moon Patrol/Dung beetles version, from within KEGS:
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BLOAD MOON PATROL
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CALL -151
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1E15:EA
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919G
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and it will work fine.
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If you have the booting version that just has Moon Patrol on it,
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then from any point after the crack screen is shown, enter the
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KEGS debugger (Shift-F6 or middle moust button) and then enter:
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0/1e15:ea
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g
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and then it will play fine.
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The bug is that the code executes an instruction with opcode $02,
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which is a NOP on 6502, but is a COP instruction to 65816. The
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COP instruction acts like BRK and will crash. The patch just
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makes it a real NOP.
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Microbe: Crashes upon booting.
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Code at $599E tries to pull a return address off of a location
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beneath the stack pointer and jump to it, but it doesn't add 1
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correctly so it jumps to $5917 when it meant to jump to $5918.
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On a IIgs, this causes a BRK to be executed and the game to crash.
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This can be patched in memory in two places:
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0/599e:ba ca 9a 7d 00 01 48 98 7d 01 01 9d 01 01 60
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0/6f1d:ba ca 9a 7d 00 01 48 98 7d 01 01 9d 01 01 60
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The original byte sequence for both locations is:
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00/599e: ba TSX
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00/599f: 7d ff 00 ADC $00ff,X
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00/59a2: 85 94 STA $94
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00/59a4: 98 TYA
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00/59a5: 7d 00 01 ADC $0100,X
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00/59a8: 85 95 STA $95
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00/59aa: 6c 94 00 JMP ($0094)
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You can also patch the code onto the disk image. I found
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the $599E version on Track $05, Sector $06, Byte $9E.
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I found the $6F1D version on the image at Track $0C, Sector $00,
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at byte $1D.
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