Author Topic: Whats wrong with my dividing script? ASM TI 83/84+ (Read 5521 times)

Jerros · « **on:** May 09, 2010, 11:23:32 am »

What I want the next piece of scrip to do is:
-Increase (score) by 1
-Divide (score)/16 (lets just call the result "P")
-I only care about WHOLE numbers, I don't need the remainder.
-Do: 63-P (which will result, lets say: "Q")
-Load Q into (scoreMeter)

Code: [Select]

	LD	A, (Score)
	INC	A
	LD	(Score), A
	LD	HL, (score)
	ADD	HL, HL
	ADD	HL, HL
	ADD	HL, HL
	ADD	HL, HL
	LD	DE, $100
	ADD	HL, DE
	LD	A, H
	NEG
	LD	B, 63
	ADD	A, B
	LD	(ScoreMeter), A

The idea is that there's a meter to show you you're score.
The value in (scoremeter) will be used as an Y-coordinate for the sprite of the meter.
But the above script doesnt really work (which you of course find obvious n_n).

Any help would be apreciated!
Thank you in advance.

Quigibo · « **Reply #1 on:** May 09, 2010, 12:17:54 pm »

"Score" and "score" are not the same variable right? Because you when you inc the score, you're only inc-ing the low byte. So if your score was 255, then the inc would make it zero again. Do this instead:

Code: [Select]

	LD	HL, (Score)
	INC	HL
	LD	(Score),HL

And then the score is already in HL for the rest of it. On the other hand, if your score is a 1 byte variable, you never want to load it into HL directly becasue the high byte will be random. Do this instead:

Code: [Select]

	LD	A, (Score)
	INC	A
	LD	(Score), A
	LD	H,0
	LD	L,A

Also, when you do those add hl,hl that multiples it by 2, it doesn't divide by 2. If you want to divide by 2, you can do a bunch of these instead:

Code: [Select]

	SRL	H
	RR	L

This divides HL by 2.

Jerros · « **Reply #2 on:** May 10, 2010, 01:22:13 am »

Ok, I'll try that, thanks.
Oh, and "Score" and "score" are the same variable, just a typo from me >.<
The Idea was that ny multiplying, I would get the Division into H:

Code: [Select]

    LD    HL, (Score)      ; Score holds any number from 0 to 992 (16*62)

; 256 ÷ 16 = 16, find (Score) × 16
; Lets say (score) = 139, so I want 8 as my answer:
    ADD    HL, HL    ; HL = $0116
    ADD    HL, HL    ; HL = $022C
    ADD    HL, HL    ; HL = $0458
    ADD    HL, HL    ; HL = $08B0      ; Tadaa! H holds 8 right? which is 139/16!

	LD	DE, $100
	ADD	HL, DE       ; HL = $09B0
	LD	A, H          ; A = 9
	NEG                       ; A = -9
	LD	B, 63
	ADD	A, B         ; A = 54
	LD	(ScoreMeter), A      ; Scoremeter = 54! Exept that it isn't for some reason...

Somewhere's a flaw, but I dont see it...
Anyway, I'll try your code, it seems shorter, faster and thus better, so if that works it's not really important why my script doesnt work.
Thanks again Quigibo, this is the 3rd time already you've helped me

Quigibo · « **Reply #3 on:** May 10, 2010, 02:12:03 am »

Yeah, that division will work as long as HL is in the range 0 - 4095. You didn't post a range earlier so I was unsure if the problem you were getting was becasue you were outside this range. Here, try this:

Code: [Select]

	LD	HL,(Score)
	INC	HL
	LD	(Score),HL
	ADD	HL,HL
	ADD	HL,HL
	ADD	HL,HL
	ADD	HL,HL
	LD	A,63
	SUB	H
	LD	(ScoreMeter),A

I am assuming ScoreMeter is a one byte variable here since it should only hold values between 0-64 correct? Which also means you should never load it into HL directly anywhere in your code. If you need it in HL at some point, you have to do this:

Code: [Select]

	LD	A,(ScoreMeter)
	LD	H,0
	LD	L,A

I suspect this might be the problem part.

Jerros · « **Reply #4 on:** May 11, 2010, 01:34:18 am »

Thanks, there should be nothing wrong with the division now, so (Scoremeter) should hold 63-((score)/16).
This means that when the score is
0-15, (scoremeter) holds 63
16-31, (scoremeter) holds 62
32-47, (scoremeter) holds 61
ect.
This still isn't working, but at least now the problem isn't this part of the script, but I still can't spot anything why my script still isnt working...
There's 2 things not workingin my script, this and something else, so there might be a connection.
I don't want to post the whole thing, since I cant ask from anyone to quickly correct quite a big piece of code.

Anyway, thanks for your help.
I hope I can figure things out myself, but otherwhise I might need your help once more >.<
My game is nearly finished, and it hurts to see things not working properly when I'm so close to the finish line...
So thanks for helping me with the division part!

tr1p1ea · « **Reply #5 on:** May 11, 2010, 04:48:34 am »

Is 'score' only 1 byte?

You could try using RLD sorta like:

Code: [Select]

    ld hl,score
    inc (hl)
    ld e,(hl)
    rld
    ld (hl),e
    and %00001111
    sub 63
    neg
    ld (scoreMeter),a

Maybe?

Jerros · « **Reply #6 on:** May 11, 2010, 06:45:00 am »

Thanks for your reply, tr1p1ea, but I stick with waht Quigibo told me.
That looks like it works fine, so my problem must be somewhere else.

Can't I delete my topic once I've had my answer? :O

tr1p1ea · « **Reply #7 on:** May 11, 2010, 07:31:24 am »

Maybe you could post more of your code if you're unsure where the problem lies? We will do our best to help you out any way we can.

Also i wouldnt recommend deleting the topic since it could prove helpful to others in the future.

Jerros · « **Reply #8 on:** May 11, 2010, 08:56:33 am »

Ok, good reason not to delete ^^
I found WHAT is making the lot crash, but I'm really really puzzled on WHY its making things crash.
Heres the thing:
(this is just a small piece, there's more but I dont want to bother you with it unless you think it might be usefull to post)

Code: [Select]

	
             CALL	gamescreen
	CALL	newsprr1n1
	LD	A, 9
	LD	B, A
tbdn1:
	CALL	hidemoveshowncount
	djnz	tbdn1
	CALL	newsprr2n2
	LD	A, 9
	LD	B, A
tbdn2:
	CALL	hidemoveshowncount
	djnz	tbdn2
	CALL	newsprr3n3
	LD	A, 9
	LD	B, A
tbdn3:
	CALL	hidemoveshowncount
	djnz       tbdn3
ect. ect. ect. ect. untill:
	CALL	newsprr4n14
	LD	A, 9
	LD	B, A
tbdn14:
	CALL	hidemoveshowncount
	djnz	tbdn14
	CALL	newsprr5n15
	LD	A, 9
	LD	B, A
tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	CALL	newsprr1n16       ; THIS is where it crashes. Works fine up to this point. It doesnt matter what number I use, newsprr@@n$$ (with @@ being a number between 1-5 and $$ is 1-16) wil ALWAYS result in ram-cleared.

To help you help me, the "CALL newsprr@@n$$" (with @@ being a number between 1-5 and $$ is 1-16) is this:

Code: [Select]

newsprr@@n$$:
	CALL	newrow@@call							   <-- here
	CALL	newspr$$call ; THIS doesnt ever get executed, so the problem must be   ^
	CALL	putnewcall
	ret

The error must be in "CALL newrow@@call", because If I remove the rest, the script still fails:

Code: [Select]

tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	JP	thebluedanubescrn  	; WORKS! it jumps and all is OK.


tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	CALL	newrow@@call		; FAILS, the jump doesnt get executed and the program crashes.
	JP	thebluedanubescrn

So what's in "newrow@@call" ?
This is:
(remember, @@ = 1 to 5, but it doesnt matter what I use, it always fails)

Code: [Select]

newrow@@call:
	LD	A, "insert any number here"
	LD	(xpos), A
	ret

Now , lets remove the call So I can see what causes the trouble:

Code: [Select]

tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	LD	A, "insert any number here"	; = 	CALL	newrow@@call
	LD	(xpos), A			; = 	CALL	newrow@@call
	JP	thebluedanubescrn		; Doesnt get executed, ram-reset here ^

The above fails, So I remove 1 line to close in the Problem:

Code: [Select]

tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	LD	A, "insert any number here"
	; Removed "LD	(xpos), A"
	JP	thebluedanubescrn		; Still doesnt get executed, ram-resets.

So now we've got:

Code: [Select]

[code]
tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	JP	thebluedanubescrn		; Works!

tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15
	LD	A, "insert any number here"	; FAILS HERE
	JP	thebluedanubescrn		; doesnt get executed, ram-resets.

So the problem in the line --LD A, "insert random number"---
WHY does loading something into A make my ram reset?
And, whats even stranger, WHY doesnt it fail the 15 times before that?

This is why I didnt post so many details earlier, i dont wanna bother anyone...
But still, ANY help would be greatly appreciated

It's just that I'm getting really close to finish the game, but I'm puzzled by this error...[/code]

DJ Omnimaga · « **Reply #9 on:** May 11, 2010, 12:13:10 pm »

I don't recommend deleting the topic as tr1p1ea said, since it could be useful to others in the future.

Quigibo · « **Reply #10 on:** May 11, 2010, 01:05:16 pm »

I notice you're doing this a lot:

Code: [Select]

ld A,<some number>
ld B,A

You can load it directly instead.

Code: [Select]

ld B,<some number>
Secondly, you use djnz around a lot of subroutines. Are you absolutely sure none of those subroutines are using the b register? Because if any of them are, it will completely screw up the counting for the djnz. If you use any bcalls in that routine, that also counts becasue bcalls generally mess up all the registers unless it specifically says it does not.

Code: [Select]

tbdn15:
	CALL	hidemoveshowncount
	djnz	tbdn15

If you can't avoid getting rid of b from the subroutine, you can save it before calling the subroutine and then restore it after with a push and pop.

Code: [Select]

tbdn15:
	PUSH	BC
	CALL	hidemoveshowncount
	POP	BC
	djnz	tbdn15

Jerros · « **Reply #11 on:** May 12, 2010, 01:25:53 am »

Loading directly into B is much smarter ofcourse, I do that everywhere.
I'm not sure why I didn't do that here :O
But you can't do:

   LD B, (label)

Right?
That would still need the:

   Ld A, label
   Ld B, A

Apart from that, the CALL hidemoveshowncount Started with:

Code: [Select]

hidemoveshowncount:
	LD	A, B
	LD	(counter), A
           ---code with lots of stuff, calls ect.---
	LD	A, (counter)
	LD	B, A
	ret

But I'm using puch/pop now.
push/pop is smarter, thnx, that works perfectly fine.

Anyway, the main problem was:
Why did the 16th " LD A, *number*" caused a crash?
Do I have to post the big "hidemoveshowcount" routine for that?
It's quite large...

I suppose it doesnt really matter now that I'm avoiding that command and just load things directly into B, but I'm still curious, and it might error again.
I need to test some more things, but for now I'm avoiding the problem, rather then fixing it.

Oh, and one last question, is it possible to do something like:

Code: [Select]

	djnz	"CHANGING LABEL"

I mean having a Jump command to a different label each time it passes that line?

Once again, BIG Thank-You! to the people that helped me here (especcially Quigibo again n_n)

tr1p1ea · « **Reply #12 on:** May 14, 2010, 08:14:02 am »

Yes it is possible to change where a djnz will jump to ... but with djnz, that might be dangerous.

Since 'code' is simply made up of bytes in RAM, you can change them just as you would any other byte.

Author Topic: Whats wrong with my dividing script? ASM TI 83/84+ (Read 5521 times)

Jerros

Whats wrong with my dividing script? ASM TI 83/84+

Quigibo

Re: Whats wrong with my dividing script? ASM TI 83/84+

Jerros

Re: Whats wrong with my dividing script? ASM TI 83/84+

Quigibo

Re: Whats wrong with my dividing script? ASM TI 83/84+

Jerros

Re: Whats wrong with my dividing script? ASM TI 83/84+

tr1p1ea

Re: Whats wrong with my dividing script? ASM TI 83/84+

Jerros

Re: Whats wrong with my dividing script? ASM TI 83/84+

tr1p1ea

Re: Whats wrong with my dividing script? ASM TI 83/84+

Jerros

Re: Whats wrong with my dividing script? ASM TI 83/84+

DJ Omnimaga

Re: Whats wrong with my dividing script? ASM TI 83/84+

Quigibo

Re: Whats wrong with my dividing script? ASM TI 83/84+

Jerros

Re: Whats wrong with my dividing script? ASM TI 83/84+

tr1p1ea

Re: Whats wrong with my dividing script? ASM TI 83/84+