Expanded out-of-range-error fixing tutorial

Right.


Out-of-range errors happen when you add code and a branch routine points to a subroutine that is out of range for the selected branch type.


Let's have a quick look at all branch types.

• BRA
  
• BSR
  

The following ones are used after a CMP command

• BLT
  
• BEQ
  
• BNE
  
• BLE
  
• BGT
  
• BGE]
  

BRA: Branch to a location


BSR: Branch to a subroutine


AFTER CMP:


BLT: Branch if less


BEQ: Branch if equal


BNE: Branch if not equal


BLE: Branch if less or equal


BGT: Branch if greater


BGE: Branch if greater or equal


BRA and BSR can be fixed in the following way:

Code:

   bra.&#40;s or w&#41; <label>

Code:

   bsr.w <label>

Are changed to

Code:

jsr <label>

For all the CMP commands you have to be careful when fixing them.



Fixing a BLT:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   blt.s RoutineLess44; If it's less than that, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bge.s RoutineGreaterOrEqual44; If it's greater or equal, branch

   jsr RoutineLess44





RoutineGreaterOrEqual44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

What we've done here is to revert the "Less" -- So if it isn't less then it of course has to be "Greater or Equal". We made the branch to point to the code that would've happened if d0 was lower than $44.





Fixing a BEQ

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   beq.s RoutineEqual44; If it's equal, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bne.s RoutineNotEqual44; If it's not equal, branch

   jsr RoutineEqual44





RoutineNotEqual44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

Self explantatory, I guess.



Fixing a BNE is following the exact same pattern.

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bne.s RoutineNotEqual44; If it's not equal, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   beq.s RoutineEqual44; If it's equal, branch

   jsr RoutineNotEqual44





RoutineNotEqual44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

Fixing a BLE is pretty easy too.

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   ble.s RoutineLessOrEqual44; If it's less or equal, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bgt.s RoutineGreater44; If it's greater, branch

   jsr RoutineLessOrEqual44





RoutineGreater44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

Fixing a BGT is easy again.

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bgt.s RoutineGreater44; If it's greater, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   ble.s RoutineLessOrEquall44; If it's greater, branch

   jsr RoutineGreater44





RoutineLessOrEqual44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

Fixing a BGE

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bge.s RoutineGreaterOrEqual44; If it's greter or equal, branch

   nop; Code that comes after

   move.b #$45,d0

   (...)

Will change to:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   bne.s RoutineNotEqual44; If it's not equal, branch

   jsr RoutineGreaterOrEqual44





RoutineNotEqual44:

   nop; Code that comes after

   move.b #$45,d0

   (...)

I hope you've understood it better now.


By the way, if you add new code, I suggest you to add it at the end of the ASM file (but before the END command of course)

 

I get Selbi's and I don't get yours. And you fail at spelling understandable.

 

I agree I think Selbi's is easier and his tutorial on it is better than yours... I actually understand Selbi's tutorial...


EDIT: You spelled "understandabl" wrong... xD... it's understandable...

 

Not necessarily, some can be used after the tst command

Firstly bsr can be bsr.s or bsr.w and secondly bsr should be changed to jsr and bra should be changed to jmp.

First of all if it is less then it will continue this code "RoutineGreaterOrEqual44:" unless you use a jmp (same for all of them with jsr in that instance). Secondly you could just do:

Code:

   cmpi.(b/w/l) $44,d0; Is value $44 in d0?

   blt.s JmpToRoutineLess44; If it's less than that, branch

   nop; Code that comes after

   move.b #$45,d0

   rts



JmpToRoutineLess44:

   jmp RoutineLess44

   (...)

If you don't have the rts it will continue and jump to the subroutine anyway.

The second branches if greater than, you'd want a bge which is greater than or equal.

This is branching if less than or equal, you'd want blt.

If it's less than this is branching, if it's greater than, it's branching. You'd want a ble.


At the bottom of this, there's a section called "Condition Codes for Bcc, DBcc and Scc Instructions" which would seem to help you, you seem to be confused on a few things.

 

Holy crap, this is confusing ... I like Selbi's tutorial better... It's easier to understand...

 

I followed all the steps in your BNE guide, it didn't worked, sorry.

 

Are you fucking kidding me? My guide is shit but this one is awesome? The only thing you made, was to add the other branch types (BLT, BGT,....)! Sorry, but you failed at this. It's not understandable (for me). Also, I hate these Code-Box. They are such annoying with their replacing system (Tab with a normal Space)! Next time use the ASM-Box or I'll get mad! And, I guess you just made the guide to bug me. Don't think I want to be your friend anymore!


Just to say something.


~Selbi

 

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