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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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 Posted: 21 Dec 2008 08:29:30 pm Post subject: |
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I'm trying to read the address of the start of data from the VAT entry for a picture, but I can't get the right value.
This is what I have:
Code:
ld HL, Pic1 ;Put VAT location in HL
b_call(_Mov9ToOP1)
b_call(_ChkFindSym)
;Get data location
dec HL ;Data location starts at VAT location - 3
dec HL
dec HL ;This givesthe correct address of the 'start of data', so the problem must be somewhere after here
ld A, (HL) ;get the data location into HL
dec HL
ld H, (HL)
ld L, A
push HL ;display data location
b_call(_ClrLCDFull)
b_call(_HomeUp)
pop HL
b_call(_DispHL)
ret
Pic1:
.db $07, tVarPict, tPic1, $00
Here are the data addresses and what this program gives me (P):
Pic1: Actual=A0C6, P=A110
Pic2: Actual=A3C5, P=A40F
Pic3: Actual=9DC7, P=9E11
The difference between them is the same, but that value isn't constant. It seems to hange after resetting the calc, so I can't just add/subtract the offset since it can change.
Any help would be appreciated.
ps: If it turns out to be a really stupid/simple mistake, don't worry about trying to phrase it nicely. |
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benryves
Active Member
Joined: 23 Feb 2006
Posts: 564
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| Posted: 21 Dec 2008 09:02:25 pm Post subject: |
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_ChkFindSym returns a pointer to the variable data in DE. Picture variables, like program variables and appvars, have a two-byte size prefix (always 63*12=756 for pictures) so you'll need to INC DE twice to point at the pixel data.
Last edited by Guest on 21 Dec 2008 09:02:49 pm; edited 1 time in total |
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calc84maniac
Elite
Joined: 22 Jan 2007
Posts: 770
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| Posted: 21 Dec 2008 09:12:08 pm Post subject: |
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The difference between them is probably because your program is loaded into the start of userMem before being run.  Then the pic moves forward a bit in memory. When the program exits, the copy gets deleted and the pic moves back. |
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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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| Posted: 21 Dec 2008 09:22:57 pm Post subject: |
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benryves wrote: _ChkFindSym returns a pointer to the variable data in DE. Picture variables, like program variables and appvars, have a two-byte size prefix (always 63*12=756 for pictures) so you'll need to INC DE twice to point at the pixel data.
[post="130573"]<{POST_SNAPBACK}>[/post]
I was using that, but it wasn't giving me the right answer either so I tried using the VAT entry. Using the DE pointer I get $A0E5 when it should be $A0C6.
Even though there's an easier way to do it, is the code I posted valid or is there a problem with it?
I'm using CalcSys to get the true location of the data and Wabbit with an 84+SE ROM if it matters.
[edit] calc84maniac wrote: The difference between them is probably because your program is loaded into the start of userMem before being run. Then the pic moves forward a bit in memory. When the program exits, the copy gets deleted and the pic moves back.
[post="130574"]<{POST_SNAPBACK}>[/post]
So the location of the pic data is different when there's a program running?
Last edited by Guest on 21 Dec 2008 09:24:24 pm; edited 1 time in total |
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calc84maniac
Elite
Joined: 22 Jan 2007
Posts: 770
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| Posted: 21 Dec 2008 09:29:24 pm Post subject: |
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| If you're using the pic data while your program is running, you won't have to worry about it. The problem was that Calcsys wouldn't give you an accurate account of where the pic was at runtime because of data shifting. |
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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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| Posted: 21 Dec 2008 09:33:05 pm Post subject: |
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calc84maniac wrote: If you're using the pic data while your program is running, you won't have to worry about it. The problem was that Calcsys wouldn't give you an accurate account of where the pic was at runtime because of data shifting.
[post="130577"]<{POST_SNAPBACK}>[/post]
Okay, thanks :biggrin:. I've been trying to figure out why I couldn't get the right address for a few hours 
I will be using the pic data from within the program so it should be fine.
Last edited by Guest on 21 Dec 2008 09:34:24 pm; edited 1 time in total |
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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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| Posted: 22 Dec 2008 12:13:25 am Post subject: |
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I needed to find the address of pic data for a program to copy one Pic to another without modifying the graphscreen or buffer. Since this is my first actual program, could someone look it over and see if there are any potential issues with it. I've tested it and haven't found anything, but I want to be sure.
Code:
.nolist
#include "ti83plus.inc"
.list
.org $9D93
.db t2ByteTok, tAsmCmp
;Copy Pic# Ans(1) to Pic# Ans(2)
b_call(_AnsName)
b_call(_FindSym) ;pointer to data in DE
jp C, _NoAns ;if Ans isn't list, skip everything
and $1F
cp $01
jr NZ, _NoAns
inc DE ;skip length bytes
inc DE
ld H, D ;need pointer in HL
ld L, E
push HL ;save pointer
call GetPicNum ;First pic, modify name
ld (FirstPic + 2), A
pop HL ;Second pic, modify name
ld BC, $09 ;Increment to second number
add HL, BC
call GetPicNum
ld (SecondPic + 2), A
ld HL, FirstPic ;get pointer to FirstPic data
b_call(_Mov9ToOP1)
b_call(_ChkFindSym)
jr C, _NoAns ;if no pic, skip to end
inc DE ;skip length bytes
inc DE
push DE
ld HL, SecondPic ;get pointer to SecondPic data
b_call(_Mov9ToOP1)
b_call(_ChkFindSym)
jr NC, _Okay
b_call(_CreatePict)
_Okay:
pop HL
ld A, $F4;set length bytes
ld (DE), A
inc DE
ld A, $02
ld (DE), A
inc DE
ld BC, $02F4 ;copy source pic to other pic
ldir
_NoAns:
ret
GetPicNum: ; in: HL=pointer to num, out: A=number
b_call(_Mov9ToOP1)
b_call(_ConvOP1);integer in E (<256)
ld A, tPic1 - 1
add A, E
ret
FirstPic:
.db $07, tVarPict, tPic1, $00;tPic1 == FirstPic + 2
SecondPic:
.db $07, tVarPict, tPic1, $00
.end
.end
The input is {A,B:Asm(prgmCOPYPIC to copy PicA to PicB.
Thanks
[edit] Fixed error in the code. I had and A instead of and $1F
Last edited by Guest on 12 Jul 2010 01:42:14 am; edited 1 time in total |
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Mapar007
Advanced Member
Joined: 04 Oct 2008
Posts: 365
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| Posted: 22 Dec 2008 06:54:25 am Post subject: |
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I think you should replace
Code:
b_call(_AnsName)
b_call(_FindSym)
with:
Code:
b_call(_RclAns)
Just for optimization  (I don't know whether it has any other advantage lol)
And why the and a?
to switch the pointers, use: ex de,hl
And instead of jp c, _NoAns and jp nz, _NoAns, use ret c and ret nz respectively.
And to find pics, you use _FindSym and not _ChkFindSym
I don't see any other issues, but I don't have that much experience after all  |
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calc84maniac
Elite
Joined: 22 Jan 2007
Posts: 770
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| Posted: 22 Dec 2008 10:00:17 am Post subject: |
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Mapar007 wrote: I think you should replace
Code: b_call(_AnsName)
b_call(_FindSym)
with:
Code: b_call(_RclAns)
Just for optimization (I don't know whether it has any other advantage lol)
[post="130587"]<{POST_SNAPBACK}>[/post]
Actually, _RclAns is fairly useless unless you're wanting Ans to be a number. If Ans was a list, _RclAns would do the same thing as _AnsName.
(I think.) |
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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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| Posted: 22 Dec 2008 10:40:44 am Post subject: |
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Mapar007 wrote: And why the and a?
FindSym returns the object type in A, but bits 5-7 are garbage, so AND $1F takes care of that.
Quote: to switch the pointers, use: ex de,hl
Good idea. I always forget about ex.
Quote: And instead of jp c, _NoAns and jp nz, _NoAns, use ret c and ret nz respectively.
I'll try that. Thanks
Last edited by Guest on 12 Jul 2010 01:42:35 am; edited 1 time in total |
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Mapar007
Advanced Member
Joined: 04 Oct 2008
Posts: 365
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| Posted: 22 Dec 2008 10:42:52 am Post subject: |
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| _RclAns sets up pointers to Ans if not real, _AnsName just sets OP1 to $00,$72 and seven other $00 bytes. (tAns, actually, $0072) |
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simplethinker
snjwffl
Active Member
Joined: 25 Jul 2006
Posts: 700
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| Posted: 22 Dec 2008 11:41:26 am Post subject: |
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I just tried using _RclAns. The good news is that it cut 3 bytes from the program size , the bad news is the program doesn't work now :(
I also realized I didn't have to manually put in the length bytes, since both pics are the same size. This changed
Code:
_Okay:
pop HL
ld A, $F4;set length bytes
ld (DE), A
inc DE
ld A, $02
ld (DE), A
inc DE
ld BC, $02F4 ;copy source pic to other pic
ldir
to
Code:
_Okay:
pop HL
ld BC, $02F6;copy source pic to other pic
ldir
and I was able to cut out the two pairs of inc DE when getting the pointers.
[edit][s]I have one more question. Is there a command/b_call that converts a one-byte integer to a floating point number? I can't find anything in the list of b_calls, but I might not be searching for the right keyword.[/s]
[another edit] [s]Better yet, is there something to turn a two-token string into a floating-point number (i.e. turn "FF" into $00, $82, $25, $50, $00, $00, $00, $00, $00). I have a routine to get the string into an integer, but it's a bit lengthy.[/s]
[another another edit] I figured it out (using _SetXXXOP1). I just need to compensate if the number is over 99.
Last edited by Guest on 12 Jul 2010 01:41:52 am; edited 1 time in total |
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calc84maniac
Elite
Joined: 22 Jan 2007
Posts: 770
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| Posted: 22 Dec 2008 12:39:22 pm Post subject: |
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Mapar007 wrote: _RclAns sets up pointers to Ans if not real, _AnsName just sets OP1 to $00,$72 and seven other $00 bytes. (tAns, actually, $0072)
[post="130591"]<{POST_SNAPBACK}>[/post]
No, this is not true. If it's not real, it puts a name you can _FindSym into OP1, otherwise it puts the number into OP1. I'm pretty sure here.
Oh, and _SetXXXXOp2 will put the value in HL into OP2 as long as 0<=HL<=9999 (which works for your purposes).
Edit: Also, you put and a instead of and $1f, which is why he asked. :)
Edit2: I found a demonstrated use of _RclAns on another site:
Code:
b_call(_RclAns)
ld a,(op1)
cp 04h
ret nz
b_call(_ChkFindSym)
So it seems I am right. :D
Edit3: From other places in my Google search, it seems that we are both right. Hmm. It puts the name in OP1 and returns the pointers.
Last edited by Guest on 12 Jul 2010 01:38:37 am; edited 1 time in total |
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Mapar007
Advanced Member
Joined: 04 Oct 2008
Posts: 365
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| Posted: 23 Dec 2008 03:13:15 am Post subject: |
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| Yes of course... should have seen it (I used a similar piece of code myself lol) |
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Z80 & 68k Assembly => z80 & ez80 Assembly
