Code issues

[BippyM]

move.w 	#%1000010111000000, DMACON(a6)	; DMA set ON
	move.w 	#%0000000000111111, DMACON(a6)	; DMA set OFF

What is this doing.

I know what being set/unset. Am I right is assuming the first call to the DMA ON turns on the Blitter, Copper and Bitplane DMA and DMA Enable.

Do the other DMA channels remain enabled, so the second DMA call is to turn them off?

[hitchhikr]

The second call disable audio DMA, disk DMA and sprites DMA only.

[BippyM]

Yes this is what I meant. Do they remain enabled and the first call just enables what's been specified?

For example

move.w #$7fff,DMACON    ; Disable all DMA(a6)
move.w #$85C0,DMACON(a6)    ; Enable Blitter, Copper, Bitplane DMA

Would give the same result?

[Thorham]

Originally Posted by bippym

Do they remain enabled and the first call just enables what's been specified?

Yes. First move only enables specified bits, second move only disables specified bits.

[BippyM]

Cool. Things are making sense now.

[Vikke]

bippym,

how is your code coming along? Have you made any MC68k-programs before?

I am now preparing some more code for release during the weekend.

[BippyM]

I've done some whdload patching (with help from Stingray, Galahad and Codetapper) and I am comfortable with basic cracking etc..

As for actually written. Something.. nope not sure bean.. always got stuck with what to do lol.

It takes forever due to family and work, but I'm getting there. Started creating the copperlist which will have all the register stuff in it..

Off to the gym now..

[BippyM]

Guys,

Below is my code, but for some reason it just reboots the amiga... I cannot see why.

I have written this pretty much myself, so there will be issues. You can see where I've commented stuff out to try and pinpoint the issue, but when I step through the debugger freezes on the dbf loop, although there is no reason why it should!

If I just enable the BSR jumps at the beginning (and re-insert the RTS's) it will hang too..

; 8 Col screen 1
; Open an 8 colour low-res screen, and display a picture in asm.
;
; 19/3/2013 14:30
;
; Process for opening the screen is:
;
; 1). Backup current system. View, Copper,DMA, Audio/Disk controller (ADKON), Interrupts (INTENA, INTREQ)
; 2). Load in the GFX file and setup the bitplane pointers
; 3). Setup the palette
; 4). Create my copperlist (Include the enabling of the DMA, interrupts etc)
; 5). Copy the copper address into COP1
; 7). Start the copper to display the picture
; 8). Display picture for 5 seconds (or so)
; 9). Restore the system copper(s), view and DMA, Interrupts etc
; 10). Exit the program


	incdir "mark_asm:open_screen/"

; Some equates for hardware and libary offsets

; Base custom address

CUSTOM			equ		$dff000

; Read addresses
DMACONR			equ		$002
ADKCONR			equ		$010
INTENAR			equ		$01c
INTREQR			equ		$01e

; Write addresses
DMACON			equ		$096
ADKCON			equ		$09e
INTENA			equ		$09a
INTREQ			equ		$09c
BPLCON0			equ		$100
BPLCON1			equ		$102
BPL1MOD			equ		$108
BPL2MOD			equ		$10a
DIWSTRT			equ		$08e
DIWSTOP			equ		$090
DDFSTRT			equ		$092
DDFSTOP			equ		$094
BPL1PTH			equ		$0e0
BPL1PTL			equ		$0e2
BPL2PTH			equ		$0e4
BPL2PTL			equ		$0e6
BPL3PTH			equ		$0e0
BPL3PTL			equ		$0e2
BPL4PTH			equ		$0e4
BPL4PTL			equ		$0e6
BPL5PTH			equ		$0e0
BPL5PTL			equ		$0e2
BPL6PTH			equ		$0e4
BPL6PTL			equ		$0e6
COP1LCH			equ		$080
COP1LCL			equ		$082
COP2LCH			equ		$084
COP2LCL			equ		$086
COPJMP1			equ		$088
COPJMP2			equ		$08A


; Library offsets

execbase		equ		$4
openlibrary		equ		-552
closelibrary	equ		-414
forbid			equ		-132
permit			equ		-138
supervisor		equ		-30
loadview		equ		-222
waittof 		equ		-270
ownblitter		equ		-456
disownblitter	equ		-462
waitblit		equ		-228

; My offsets
old_View_off	equ		34
old_Clist1_off	equ		38
old_Clist2_off	equ		50

begin:

	movem.l		d0-d7/a0-a6,-(sp)				; Backup the system registers
	jsr			closesys
;	jsr			mysys
;	jsr			restoresys
	
libfail:
	movem.l		(sp)+,d0-d7/a0-a6
	moveq.l		#0,d0							; No returncode to AmigaDOS
	rts

; First we backup the system and then take control

closesys:
	move.l		execbase,a6						; Address of execbase into a6
	lea			gfxlibraryname,a1				; address of the gfx lib into a1
	moveq.l		#0,d0							; version of the library
	jsr			openlibrary(a6)					; Open the library, address is returned in d0
	move.l		d0,gfxbase						; store the address of the library
	move.l		d0,a6							; Graphics library base address into a6
	beq			libfail							; Returned a 0 in d0, then lib failed to open. Let's quit
	
	; Store the current system view and copperlists so we can restore them later
	
	move.l		old_View_off(a6),sysview
	move.l		old_Clist1_off(a6),sys1cop
	move.l		old_Clist2_off(a6),sys2cop
	
	sub.l		a1,a1							; Null view for a blank screen
	jsr			loadview(a6)					; Clear the screen
	jsr			waittof(a6)						; Wait for the top of the next frame
	jsr			waittof(a6)						; Wait again
	jsr			ownblitter(a6)
	jsr			waitblit(a6)

	; Save the contents of the sys registers (DMA, ADKON, INTENA, INTREQ)
	
	lea			CUSTOM,a6						; Base address $dff000
	
	move.w		DMACONR(a6),d0					; Store the contents of the DMA
	or.w		#$8000,d0						; Set it for re-writing later
	move.w		d0,sysdma						; store for later
	move.w		ADKCONR(a6),d0					; Store the contents of the ADKCON register
	or.w		#$8000,d0						; Set it for re-writing later
	move.w		d0,sysadkcon					; store for later
	move.w		INTENAR(a6),d0					; Store the contents of the interrupt-enable
	or.w		#$8000,d0						; Set it for re-writing later
	move.w		d0,sysintena					; store for later	
	move.w		INTREQR(a6),d0					; Store the contents of the interrupt-request
	or.w		#$8000,d0						; Set it for re-writing later
	move.w		d0,sysintreq					; store for later

	; System is now backed up, let's take it
	
	move.l		execbase,a6
	jsr			forbid(a6)						; Disable the system
	
	move.l	#$7fff,DMACON(a6)					; Disable all DMA channels
	move.l	#$85C0,DMACON(a6)					; Enable Blitter, Copper, Bitplane DMA and turn DMAEN on and enable
	move.w 	#%1100000000000000, INTENA(a6)	; IRQ set ON
	move.w 	#%0011111111111111, INTENA(a6)	; IRQ set OFF
;rts

mysys:

; Work out the bitplane sizes and addresses and pass to the copperlist.
; Bitplane info: 320*256*8. 40 words per line, 256 lines. 320x356/8bits = 10240bytes
; 10240*5=50kb : 2560 longs per bitplane
;
	lea			bp1h,a0							; first bitplane address in the copper
	moveq		#3-1,d0								; Number of bitplanes
	move.l		#image,d1							; Address of the picture into d1

	setbpl:
		move.w	d1,6(a0)							; bitplane low address pointer
		swap	d1
		move.w	d1,2(a0)							; bitplane high address
		addq.w	#8,a0
		swap d1
		add.l 	#40*256,d1							; 10240 added for next plane
	dbf d0,setbpl									; branch until all bitplanes are copied

	; load the copperlist into cop1lc
	lea mycopper,a0									; Copper address into s1
	move.l a0,COP1LCL(a6)								; and into the Cop1 register
	move.w	d0,COPJMP1(a6)								; Start the copper
	
	
		
	; Need to enable the following DMA channels: Copper, DMA, Blitter and Bitplane
		
	waitmouse:	btst	#6,$bfe001
		bne	waitmouse

		moveq	#0,d0
;		rts
rts
	
; My data structures, this includes the copperlist
	CNOP	0,4											; Ensure we are on an even address!

sys1cop:			dc.l	0							; To store the address of the first system copperlist
sys2cop:			dc.l	0							; and the second system copperlist
sysview:			dc.l	0							; The address to the system view
gfxbase:			dc.l	0							; To store the return address of the graphics.library if successfully opened

sysdma:				dc.w	0
sysadkcon			dc.w	0
sysintena			dc.w	0
sysintreq			dc.w	0

	CNOP	0,4
gfxlibraryname:		dc.b	"graphics.library",0		; Name of library we need
	CNOP	0,4
; All the below needs to be in chipram as it is accessed by the custom chips!

	section chipram,data_c

	; Bitplane information here. 3 bitplanes at 320x256
	even
	
;bp1:	dcb.b	10240,0									; Bitplane 1
;bp2:	dcb.b	10240,0									; Bitplane 2
;bp3:	dcb.b	10240,0									; Bitplane 3
	
	; Copperlist below. We need to setup the following:
	; BPLCON0 - Set an 8 colour, 3 bitplane display
	; BPLCON1 - Unset set horizontal scroll delay (Set to 0)
	; BPL1MOD & BPL2MOD - Set the modulo, again to 0
	; DIWSTRT - $2c81, and DIWSTOP to $2cc1
	; DDFSTRT - $0038 (Upper left), DDFSTOP to $00d0 (Lower right)
	; BPL1PTH & BPL1PTL - BPL3PTH & BPLPTL - Address for each bitplane in memory.
	even
mycopper:			
		dc.w	BPLCON0,$3200					; %0011001000000000
		dc.w	BPLCON1,$0000
		dc.w	BPL1MOD,$0000,BPL2MOD,$0000
		dc.w	DIWSTRT,$2C81,DIWSTOP,$2CC1
		dc.w	DDFSTRT,$0038,DDFSTOP,$00D0
bp1h:	dc.w	BPL1PTH,$0000					; Bitplane 1 high bytes register, use offset
bp1l:	dc.w	BPL1PTL,$0000					; Bitplane 1 high value, Bitplane 1 low register
bp2h:	dc.w	BPL2PTH,$0000					; Bitplane 1 high bytes register, use offset
bp2l:	dc.w	BPL2PTL,$0000					; Bitplane 1 high value, Bitplane 1 low register
bp3h:	dc.w	BPL3PTH,$0000					; Bitplane 1 high bytes register, use offset
bp3l:	dc.w	BPL3PTL,$0000					; Bitplane 1 high value, Bitplane 1 low register

Palette:
		dc.w $0180,$0000,$0182,$0AAA,$0184,$0004,$0186,$0444
		dc.w $0188,$0666,$018A,$0888,$018C,$0CCC,$018E,$0EEE

		dc.w $ffff,$fffe
		dc.w $ffff,$fffe
	even 		
image:	incbin "dh3:Open_Screen1/8cols.raw"

[WayneK]

	dbf d0,setbpl									; branch until all bitplanes are copied

	; load the copperlist into cop1lc
	lea mycopper,a0									; Copper address into s1
	move.l a0,COP1LCL(a6)								; and into the Cop1 register
	move.w	d0,COPJMP1(a6)

I haven't looked very hard at your code, but that "move.w d0,COPJMP1(a6)" doesn't look right to me (think about what d0 would contain at this point, immediately after finishing a dbf loop)" ?

[BippyM]

yeah -1 ($FFFF), but I thought copjmp was a strobe address, and writing anything to it will start it!.

Will change it and see what happens.

edit:

That made no difference, but the following made a slight change

move.l #$7fff,DMACON(a6)

to

move.w #$7fff,DMACON(a6)

Now it just guru's, but not resetting the same!

edit2:

the move.w #$7fff,DMACON(a6)

When this is executed, instant guru

[Thorham]

begin:

    movem.l     d0-d7/a0-a6,-(sp)               ; Backup the system registers
    jsr         closesys
;   jsr         mysys
;   jsr         restoresys

libfail:
    movem.l     (sp)+,d0-d7/a0-a6
    moveq.l     #0,d0                           ; No returncode to AmigaDOS
    rts

; First we backup the system and then take control

closesys:
    move.l      execbase,a6                     ; Address of execbase into a6
    lea         gfxlibraryname,a1               ; address of the gfx lib into a1
    moveq.l     #0,d0                           ; version of the library
    jsr         openlibrary(a6)                 ; Open the library, address is returned in d0
    move.l      d0,gfxbase                      ; store the address of the library
    move.l      d0,a6                           ; Graphics library base address into a6
    beq         libfail

Two things here:

1. When calling something like openlibrary, you have to compare the return value with 0. The system functions are not guaranteed to do that, so use a tst.l d0 before branching.

2. Look at how closesys is called, and then look at how the routine jumps back when openlibrary fails.

[StingRay]

Here's the reason for your crashes:
move.l execbase,a6
jsr forbid(a6)

move.l #$7fff,DMACON(a6) ; Disable all DMA channels
move.l #$85C0,DMACON(a6) ; Enable Blitter, Copper, Bitplane DMA and turn DMAEN on and enable
move.w #%1100000000000000, INTENA(a6) ; IRQ set ON
move.w #%0011111111111111, INTENA(a6) ; IRQ set OFF


Also, your check if gfx lib has opened OK is fine since the move.l d0,gfxbase sets the flags, there is no tst.l needed!

[Thorham]

Originally Posted by StingRay

Also, your check if gfx lib has opened OK is fine since the move.l d0,gfxbase sets the flags, there is no tst.l needed!

Since when does a move to memory test against 0 Good thing I posted here, because I didn't know that Had to test it myself, and of course it works

Originally Posted by StingRay

Here's the reason for your crashes:
move.l execbase,a6
jsr forbid(a6)

move.l #$7fff,DMACON(a6) ; Disable all DMA channels
move.l #$85C0,DMACON(a6) ; Enable Blitter, Copper, Bitplane DMA and turn DMAEN on and enable
move.w #%1100000000000000, INTENA(a6) ; IRQ set ON
move.w #%0011111111111111, INTENA(a6) ; IRQ set OFF


Also, your check if gfx lib has opened OK is fine since the move.l d0,gfxbase sets the flags, there is no tst.l needed!

He still sets a6 to custom regs:

	; Save the contents of the sys registers (DMA, ADKON, INTENA, INTREQ)
	
	lea			CUSTOM,a6

[StingRay]

Please check the code properly! Also, there was a reason I gave a rather subtle hint as I wanted Bippy to spot the error.

[Thorham]

Originally Posted by StingRay

Please check the code properly! Also, there was a reason I gave a rather subtle hint as I wanted Bippy to spot the error.

Yeah, man Back to school for me

[BippyM]

Bloody hell.. How did I miss that :/

Cheers guys.. To test

[StingRay]

Originally Posted by Thorham

Yeah, man Back to school for me

Originally Posted by bippym

but when I step through the debugger freezes on the dbf loop, although there is no reason why it should!

Just noticed this, let me guess, you're using WinUAE? If so, either enable "hard flush" in the JIT settings or disable JIT completely, Asm-One's debugger will work fine then!

Originally Posted by bippym

Bloody hell.. How did I miss that :/

Cheers guys.. To test

Another (not so) subtle hint: If you have fixed your code and then wonder why you don't see any picture it might have to do with your DMA settings.

[BippyM]

Indeed I see no picture currently. I'll look again once I can get the daughter off my PC..

Thanks for the JIT tip. Using the debugger was frustrating

[BippyM]

Wooo.. I see a picture

There's still a bit of corruption and some of the palette looks wrong, which might be due to the copper. Need to investigate further.

Exit code has now been written. Just to get the corruption gone and system stable then I plan to change bits..

[Vikke]

Bippym,

Good to know tou get the code to work at some level.

Two hints to get the copperlist working:

1. lea mycopper,a0 ==> mycopper is a pointer and has to be handled as such.

2. move.l a0,COP1LCL(a6) ==> writing the address as a longword, take care to write it to the right location.

The corrections to be made to the code are _very_ small, so don't over think them.


If you have been looking at my code examples for starting the copperlist, you have to take notice of me using 2 different copperlists and therefore I store the pointer to the copperlists in a memorylocation, and address it as such.