[Sonic 65]

I made a guide that tells you the location of parts of monitor code and what those parts do. Not much, but hey. Updates coming later.

Attached File(s)

•  objprog.txt (3.19K)
  Number of downloads: 195

[Erik JS]

Quote

I am skipping Eggman monitor programming because I don't know the ASM codes for some commands in it.

But you're talking about S1, right? It can't be S2 because monitor code in that game is at a higher address. Eggman monitor does nothing in S1, so it isn't too hard to figure out what a jump to "4E 75" does. :P

Try to put in the next update info on how to have unused monitors to do something.

[Hivebrain]

Wouldn't it be better to look at a disassembly if you want to know how things work?

[LOst]

I made a document on this in pure assembler a long time ago. You can find it here:
http://area51.ssonic...p?showtopic=193

[Hayate]

LOst, do you have a machine code to ASM table anywhere? That would help me out a lot more than this other stuff...

[Sonic 65]

I made a little machine-code-to-ASM text file sometime ago. The only problem is that it hasn't seen an update in ages. I'll update it a little and edit this post to have it attached.

Oh yeah, and Erik JS, the Eggman code is more than a jump to 4E 75.

addq.b #2, $24(a0) ;???
move.w #$1D, $1E(a0) ;???
move.b $1C (a0) ,d0 ;???
cmpi.b #1 , d0 ;Does monitor contain Eggman?
bne.s loc_A384 ;If not, branch
rts ;4E 75

NOTE: Actually, my file is ASM-to-machine code, but it can also be used vice-versa.

Attached File(s)

•  68KinHex.txt (2.83K)
  Number of downloads: 90

This post has been edited by Sonic 65: 25 October 2004 - 04:01 PM

[Rika Chou]

Very good, Sonic 65, I can tell you have put a lot of time into this.

[Sonic 65]

Thanks. Making a machine code guide isn't nearly as hard if you have a disassembly. :D

[Quickman]

Or you could just use the documentation Motorola give. That's how I learned ASM.

EDIT:

addq.b #2, $24(a0) ; advance to next object routine
move.w #$1D, $1E(a0) ; set collision size for object to $1D
move.b $1C (a0) ,d0 ; load animation frame into d0
cmpi.b #1 , d0 ; Subtract one from animation frame number (frame 1 is Eggman)
bne.s loc_A384 ; If not equal to 0 (I.e. if frame is not Eggman), continue to other frame checks
rts ; We'll reach here if it IS equal to 0 - nothing happens

This post has been edited by Quick Man: 26 October 2004 - 04:06 PM

[Hivebrain]

Quote

move.w #$1D, $1E(a0) ; set collision size for object to $1D

Isn't $1E(a0) something to do with animation? IIRC, $1A-$1E(a0) are used by the animation subroutines.

[Hayate]

Sonic 65: Sorry to sound annoying, but it doesn't have all of the commands, like ADD or BEQ (now that's useful)...

Edit: S65 for Tech Member! :D

This post has been edited by bobxp: 27 October 2004 - 09:12 AM

[Quickman]

Hivebrain, on Oct 27 2004, 01:27 PM, said:

Quote

move.w #$1D, $1E(a0) ; set collision size for object to $1D

Isn't $1E(a0) something to do with animation? IIRC, $1A-$1E(a0) are used by the animation subroutines.

I was going by MY document on the SST, hosted by drx on the Hacking CulT.

[Hivebrain]

Quick Man, on Oct 27 2004, 04:44 PM, said:

Hivebrain, on Oct 27 2004, 01:27 PM, said:

Quote

move.w #$1D, $1E(a0) ; set collision size for object to $1D

Isn't $1E(a0) something to do with animation? IIRC, $1A-$1E(a0) are used by the animation subroutines.

I was going by MY document on the SST, hosted by drx on the Hacking CulT.

That document is inaccurate. And exactly how much of the information on it did you find yourself?

[Quickman]

I have no idea. I've long since lost the original to check (it was on my old hard drive before I got my computer which for the moment doesn't suck).

[Sonic Hachelle-Bee]

Quote

Sonic 65: Sorry to sound annoying, but it doesn't have all of the commands, like ADD or BEQ (now that's useful)...

You've just asked for it.

Flags:
N: Negative. Set to 1 if result negative.
Z: Zero. Set to 1 if result is 0 (false).
V: Overflow. Set to 1 if overflow (Pos + Pos = Neg or Neg + Neg = Pos)
C: Carry.
X: Like C, Carry.

Assembly <-> Hexadecimal

MOVE.B <-> 11 FC 12 34 AB CD (Store byte 34 at RAM $ABCD)
MOVE.L <-> 21 FC 12 34 56 78 AB CD (Store long 12345678 at RAM $ABCD)
MOVE.W <-> 31 FC 12 34 AB CD (Store word 1234 at RAM $ABCD)

CMPI.B <-> 0C 38 12 34 AB CD (compare byte 34 at data from RAM $ABCD)
CMPI.W <-> 0C 78 12 34 AB CD (compare word 1234 at data from RAM $ABCD)
CMPI.L <-> 0C B8 12 34 56 78 AB CD (compare long 12345678 at data from RAM $ABCD)

BRA.S <-> 60 11 (Branch always, jump 11 bytes)
BSR.S <-> 61 11 (Branch under sub-routine)
BHI.S <-> 62 11 (Branch if C=0 and Z=0)
BLS.S <-> 63 11 (Branch if C=1 or Z=1)
BCC.S <-> 64 11 (Branch if Carry clear, C=0)
BCS.S <-> 65 11 (Branch if Carry set, C=1)
BNE.S <-> 66 11 (Branch if non equal, Z=0 (false))
BEQ.S <-> 67 11 (Branch if equal, Z=1 (true))
BVC.S <-> 68 11 (Branch if Overflow clear, V=0)
BVS.S <-> 69 11 (Branch if Overflow set, V=1)
BPL.S <-> 6A 11 (Branch if result plus, N=0)
BMI.S <-> 6B 11 (Branch if result minus, N=1)
BGE.S <-> 6C 11 (Branch if greater or equal to, N=V)
BLT.S <-> 6D 11 (Branch if lower than, N is not the same as V)
BGT.S <-> 6E 11 (Branch if greater than, N=V and Z=0)
BLE.S <-> 6F 11 (Branch if lower or equal to, N is not the same as V or Z=1)

ADD <-> 52 38 AB CD (Add 1 at value in RAM $ABCD)
ADD <-> 54 38 AB CD (Add 2 at value in RAM $ABCD)

JMP <-> 4E F9 11 11 11 11 (Jump at ROM $11111111)
JSR <-> 4E B9 11 11 11 11 (Jump at sub-routine at ROM $11111111)

NOP <-> 4E 71 (Non operation, do nothing and continue)
RTS <-> 4E 75 (Return to sub-routine)

EDIT: Examples:

RAM $FE10: Level loaded.
RAM $ FE 11: Act loaded.
RAM $ EE 00: Camera X position.
RAM $ EE 04: Camera Y position.
RAM $ F64A: Water Y height.

0C 78 04 01 FE 10 67 10
If Metropolis zone 2 (level 04 01) is loaded, jump 10 bytes.

0C 78 0E 00 EE 00 6F 08
If Camera X position is lower or equal to 0E 00, jump 08 bytes.

0C 78 15 00 EE 00 6F 10 31 FC 02 00 F6 4A
If Camera X position is greater than 15 00, set water Y height to 02 00.
Else, jump 10 bytes.

Helpful? There might be some errors, I haven't a 68K disassembly program for Mac, then I found this myself.

This post has been edited by Sonic Hachelle-Bee: 28 October 2004 - 01:10 AM