2k intro boot...

[W4r3DeV1L]

I just want to ask your help for something I always have been wondering about for many years...

let's get to it:

Assuming I have any 2k executable intro and want to experience how to write it into the bootblock can I do this job with the ASM-One/ARIII or do I need any special tool?

Sorry to ask, but I am in the dark.....

[ross]

Originally Posted by D4Ni3L3

I just want to ask your help for something I always have been wondering about for many years...

let's get to it:

Assuming I have any 2k executable intro and want to experience how to write it into the bootblock can I do this job with the ASM-One/ARIII or do I need any special tool?

Sorry to ask, but I am lin the dark.....

Booblock itself is only 1KB so you have to load the 2 additional sectors.
I have no idea if there is a special tool, but if you want I will do it for you

[W4r3DeV1L]

Originally Posted by ross

Booblock itself is only 1KB so you have to load the 2 additional sectors.
I have no idea if there is a special tool, but if you want I will do it for you

Thanks... but I prefer to learn how to do it!

Then ... assuming I have a 1k code to jam into the bootblock sectors ... how can I do this?

[ross]

Originally Posted by D4Ni3L3

Thanks... but I prefer learn how to do it!

Then ... assuming I have a 1k code to jam into the bootblock sectors ... how to do it?

In (relocated) binary form or source code?

[W4r3DeV1L]

Originally Posted by ross

In (relocated) binary form or source code?

executable...

[ross]

Ok, two possibilities:

1) the exe is fully pc relative, so you do not need to relocate it.
Simply strip the header (at start and end of the binary).
Then assemble:

bb:
  dc.b 'DOS',0
  dc.l checksum
  dc.l $370
start: incbin "your.exe"

If you want to launch system you need a little stub at end.

2) relocate the exe at some fixed location.
Then:

bb:
  dc.b 'DOS',0
  dc.l checksum
  dc.l $370
start: copy bin to right location
bin: incbin "your.exe"

But an real example sure is better

[phx]

Originally Posted by ross

Simply strip the header (at start and end of the binary).

Not sure if this will be simple for a beginner, without knowledge of the hunk format structure.

To simplify it: if you have a single-section executable the header will be 32 bytes, which you can skip. But then you lose this space in the boot block.

bb:
  dc.b 'DOS',0
  dc.l checksum
  dc.l $370
start:
  bra.b *+34
  incbin "your.exe"

Better would be to let your assembler write a raw binary file, without hunk format headers. With vasm it would be -Fbin, but IIRC you are using AsmOne? So you may assemble to memory and then save the memory contents to a file (wb command?).

[a/b]

For asm-one:
1. use this source:

start:
 DC.B 'DOS',0
 DS.L 1  ; checksum comes here
 DC.L 880

exe_code:
 DS.B 1024-12
end:

2. assemble the source with A
3. load exe into memory with RO, you will get its memory location, say it's X
4. copy exe with C (beg is X, end is X+1024-12, dest is exe_code)
5. write bb to disk as 2 sectors with WS (ram ptr is start, disk ptr is 0, length is 2)
6. calculate bootblock checksum with CC

Edit: Forgot to mention, you can simulate bootblock with BS (beg is start).

[ross]

A real example: "It's a sin" by Planet Jazz.
It's a 1KB bootblock intro with source code available, full PC relative.

I chose this because I took the opportunity to fix some small bugs that prevents it to exit to CLI regularly.

Greeting to the original coder

;Planet Jazz - It's a sin bootblock for Datastorm 2017
;Partycoded by Olle using Blueberrys bootblock examplecode.
;It's not only a sin, it is also a complete mess. :)

; little fix by ross 22/09-2019

; Bootblock example code by Blueberry / Loonies, 23/9-2012
; Public Domain

; System constants
_LVOFindResident = -96
_LVOLoadView = -222
_LVOWaitTOF = -270
gb_ActiView = 34
gb_copinit = 38
IVBLIT = 156
RT_INIT = 22
SU_tf_CharData = $22
SU_OpenFont = -72

_AUD0LCH = $A0
_AUD0LEN = $A4
_AUD0PER = $A6
_AUD0VOL = $A8
_AUD2LCH = $C0
_AUD2LEN = $C4
_AUD2PER = $C6
_AUD2VOL = $C8

Mask = 2048-1


	section	BB,code

; The bootblock starts here.
; It cannot generally be assumed to be placed in a specific
; kind of memory, or at any specific address, so all code
; must be completely PC relative, and all chip data must
; be explicitly copied to chip memory.

BB:
	DC.B	'DOS',0
	DC.L	0
	DC.L	$370

START:
	; Bootblock code goes here.
	movem.l	d0-a6,-(sp)

	; Global pointer to chip space in A4
	; Chip space at the end of (512k) chip memory
	lea	$80000-4096-(Space_End-Space),a4

	; Open topaz
;	movea.l	$4.w,a6
	movea.l	IVBLIT(a6),a6	; graphics.library
	lea	TextAttr(pc),a0
	lea	TopazName(pc),a1
	move.l	a1,(a0)
	jsr	SU_OpenFont(a6)
	movea.l	d0,a0
	move.l	SU_tf_CharData(a0),TopazCharData-Space(a4)

	lea	TextScr-Space(a4),a0
	lea	Bpl2-Space(a4),a1
	move.w	#$00e4,d1
	bsr.w	SetBpl
	addq.w	#2,d1
	adda.l	#(80*1)+2,a0
	bsr.w	SetBpl

	lea	Kottig_Text(pc),a0
	lea	TextMsg-Space(a4),a1
	moveq	#(Kottig_TextE-Kottig_Text)/4-1,d7
.tloop	move.l	(a0)+,(a1)+
	dbf	d7,.tloop

	; Copy copperlist to chip
	lea	CopperData(pc),a0
	lea	Copper-Space(a4),a1
	moveq	#(CopperData_End-CopperData)/4-1,d7
.cloop	move.l	(a0)+,(a1)+
	dbf	d7,.cloop

	move.l	#$00280078,Yptr1-Space(a4)
	
	lea	TextMsg-Space(a4),a0
	move.l	a0,Textptr-Space(a4)

	lea	$DFF000,A5
	move.w	2(a5),-(sp)
	ori.w	#$8000,(sp)

	;init sound
	lea	Waveform-Space(a4),a1
	move.w	#$7f80,(a1)

	move.l	a1,_AUD0LCH(a5)
	move.w	#1,_AUD0LEN(a5)
	move.l	a1,_AUD2LCH(a5)
	move.w	#1,_AUD2LEN(a5)

;	bsr.w	gen_sin
	lea	Bpl_Sinus-Space(a4),a0
	lea	1024(a0),a1
	moveq	#0,d4
	move	#256-1,d3
.l1	move.l	d4,d0
	swap	d0
	add.l	#823550,d4	;Pi<<18
	move	d0,d2
	move	d0,d1
	mulu	d1,d1
	lsl.l	#4,d1
	swap	d1
	mulu	d1,d0
	divu	#3<<11,d0
	sub	d0,d2
	mulu	d1,d0
	divu	#10<<11,d0
	add	d0,d2
	mulu	d1,d0
	divu	#21<<11,d0
	sub	d0,d2
	asr	#4,d2

	move	d2,(a0)+
	move	d2,2046(a0)
	move	d2,-(a1)
	neg	d2
	move	d2,1022(a0)
	move	d2,1024(a1)
	dbf	d3,.l1


;	bsr.w	render_triangle
	moveq	#0,d1
	moveq	#0,d7
	lea	TScreen-Space(a4),a0
	move.l	#640/2,d0
.floop	subq.l	#1,d0
	add.l	#80,d1
	move.w	d7,d2
	lsl.w	#1,d2

	move.l	d0,d3
.fscanl
;	bfset	(a0,d1.w){d3:01}		; 68020+ method
; 68000-method ;(
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	move.l	d3,d4				; x
	move.l	d1,d5				; y
	ror.l	#3,d4
	add.l	d4,d5				; + x position in bit(!)[*]
	rol.l	#3,d4				; /8 - now we have byte offset
	not	d4				; correct offset for bitset
	bset	d4,(a0,d5.w)
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	addq.l	#1,d3
	dbra	d2,.fscanl

	addq.w	#1,d7
	cmp.w	#320,d7
	bne.b	.floop

;	bsr.w	fill_copper
	lea	Bplist-Space(a4),a0
	move.l	#$1ee1fffe,d0
	move.l	#300-1,d1
.fill	move.l	d0,(a0)+
	move.l	#$00e00000,(a0)+
	move.l	#$00e20000,(a0)+
	add.l	#$01000000,d0
	dbra	d1,.fill

	; Set copperlist
	lea	Copper-Space(a4),a1
	move.l	a1,$80(a5)

	; Disable interrupts and set some DMAs
	move.w	#$4000,$9a(a5)
	move.w	#$87C5,$96(a5)
;	move.w	#%1000000000000101,_DMACON(a5)

	; Switch off sprite DMA
;	bsr.w	WaitVbl
	move.w	#$0020,$96(a5)

	; Main per-frame loop
MainLoop
;	bsr.w	do_sine
	move.w	Yptr1-Space(a4),d2
	move.w	Yptr2-Space(a4),d3
	lea	Bpl_Sinus-Space(a4),a0
	lea	TScreen-Space(a4),a1		; Triangle screen
	lea	Bplist-Space(a4),a2
	move.l	#300-1,d7
.loop	move.w	(a0,d2),d4
	add.w	(a0,d3),d4
	asr.w	#2,d4
	add.w	#100,d4
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	mulu	#80,d4
	add.l	a1,d4
	move.w	d4,10(a2)
	swap	d4
	move.w	d4,6(a2)
	add.l	#12,a2
;-=-=-=-=-=-=-=-=-=-=-=-=-=-=
	add.w	#8*4,d2
	add.w	#4*4,d3
	and.w	#Mask,d2
	and.w	#Mask,d3
	dbra	d7,.loop
	move.w	Yptr1-Space(a4),d2
	move.w	Yptr2-Space(a4),d3	
	add.w	#2*4,d2
	add.w	#4*4,d3
	and.w	#Mask,d2
	and.w	#Mask,d3
	move.w	d2,Yptr1-Space(a4)
	move.w	d3,Yptr2-Space(a4)

	bsr.w	write_text
	
;-------------- audio --------------
;do_drum
	cmp.w	#32,Ticks-Space(a4)
	bne.b	.ntrig
	move.w	#124,Per-Space(a4)
	move.w	#64,Vol-Space(a4)
	clr.w	Ticks-Space(a4)
.ntrig
	addq.w	#1,Ticks-Space(a4)

	move.w	Per-Space(a4),_AUD0PER(a5)
	move.w	Vol-Space(a4),_AUD0VOL(a5)

	add.w	#12<<8,Per-Space(a4)
	subq.w	#8,Vol-Space(a4)

	move.w	Per-Space(a4),_AUD2PER(a5)
	move.w	Vol-Space(a4),_AUD2VOL(a5)
;----------------------------------
	bsr.b	WaitVbl

	; Loop until LMB
	btst	#6,$bfe001
	bne.w	MainLoop

Exit:
	; Recover DMA settings
	move.w	#$7fff,$96(a5)
	move.w	(sp)+,$96(a5)

	; Restore copper
;	move.l	IVBLIT(a6),a6
	move.l	gb_copinit(a6),$80(a5)

	; Restore registers
	movem.l	(sp)+,d0-a6

	; Return init function of dos.library resident in A0
	lea	DosName(pc),a1
	jsr	_LVOFindResident(a6)
	movea.l	d0,a0
	movea.l	RT_INIT(a0),a0
	moveq	#0,d0
	rts

WaitVbl
	tst.b	5(a5)
	beq.b	WaitVbl
.wvb
	tst.b	5(a5)
	bne.b	.wvb
	rts

SetBpl
	move.l	a0,d0
	move.w	d1,(a1)+	;$00ex
	swap	d0
	move.w	d0,(a1)+	;h
	swap	d0
	addq.w	#2,d1
	move.w	d1,(a1)+	;$00ex
	move.w	d0,(a1)+	;l
	rts

;-----------------------------------

; Textwriter using Topaz font.
write_text
	lea	TextScr-Space(a4),a1
	adda.l	#80*8+20-2+((80*10)*5),a1

	movea.l	Textptr-Space(a4),a0
.getch	moveq	#0,d0
	move.b	(a0)+,d0
	beq.b	.fin			; if 0 then finished
	move.l	a0,Textptr-Space(a4)

	tst.b	d0			; repeat space $7f+no of spaces
	bpl.b	.norepspace
	sub.w	#$7f,d0
	add.w	d0,TextCursorx-Space(a4)
	bra.b	.getch
.norepspace

	cmp.b	#10,d0			; newline
	bne.b	.cont
	add.w	#80*10,TextCursory-Space(a4)
	clr.w	TextCursorx-Space(a4)
	bra.b	.getch
.cont	sub.b	#32,d0
	move.l	TopazCharData-Space(a4),a0
	add.w	d0,a0

	add.w	TextCursorx-Space(a4),a1
	add.w	TextCursory-Space(a4),a1
	moveq	#8-1,d0
.cpy	move.b	(a0),(a1)
	add.w	#192,a0
	add.w	#80,a1
	dbra	d0,.cpy
	addq.w	#1,TextCursorx-Space(a4)
.fin	rts

Kottig_Text
	dc.b	$7f+14,'At DataStorm 2017',10,10,10
	dc.b	$7f+13,'Planet.Jazz cracked',10
	dc.b	$7f+13,'Several braincells',10
	dc.b	10,10,10
	dc.b	$7f+7,'Greetings to everyone at the party',10,10
	dc.b	$7f+4,'and heck, even to the sofa-sceners :P',10
	dc.b	10,10,10,10,10,10,10
	dc.b	'partycode, same procedure as every year james.',0
	even
Kottig_TextE

CopperData
	dc.w	$0100,$b000,$008e,$2c81,$0090,$2cc1
	dc.w	$0092,$003c,$0094,$00d4
	dc.w	$0108,$0000,$010a,$0000
	dc.w	$0102,$0407
	dc.w	$0180,$05c5,$0182,$04a4
	dc.w	$0184,$0151,$0186,$0141
	dc.w	$0188,$0fef,$018a,$0fff
	dc.w	$018c,$0fef,$018e,$0fff
CopperData_End

DosName	dc.b	'dos.library',0

TextAttr
	dc.l	0
	dc.w	8
	dc.b	0,0
TopazName
	dc.b	'topaz.font',0
	even


;		section	space,bss_c
Space
Ticks		ds.w	1
Per		ds.w	1
Vol		ds.w	1
Yptr1		ds.w	1
Yptr2		ds.w	1
Sq		ds.w	1
TextCursorx	ds.w	1
TextCursory	ds.w	1
Textptr		ds.l	1
TopazCharData	ds.l	1
TextMsg		ds.b	Kottig_TextE-Kottig_Text
Bpl_Sinus	ds.w	4096
Waveform	ds.l	1
Copper		ds.b	CopperData_End-CopperData
Bpl2		ds.w	4	;dc.w	$00e4,$0000,$00e6,$0000
Bpl3		ds.w	4	;dc.w	$00e8,$0000,$00ea,$0000
Bplist		ds.w	300*6	; Triangle bitplane ptrs
		ds.l	1	; Terminator
TextScr		ds.b	80*256
TScreen		ds.b	80*640
Space_End

EDIT
Just noticed two small inaccuracies in the copper list.
But the purpose was a bb intro example so it doesn't matter

[W4r3DeV1L]

Thank you so much ross! ...

Anyway I started the .adf with WinUAE and of course it works, but ... trying to figure out how things have been done ... I opened, with ASM-One, the source file you attached "pjz-its_a_sin.s" and once assembled I haven't been able to execute anything.

Can you, ... please ... , give me/us more help telling ... how to start it and how to (maybe step by step) end up writing it into and .adf disk boot block?

It would be nice to to have the file pjz-its_a_sin.adf like the one you attached.

I have greatly appreciated your work for this bb intro example ...

[ross]

Load and assemble the source.

Then:
WS
RAM PRT>BB
DISK PTR>0
LENGTH>2
CC

What did you do in practice:
WS -> write assembled code to disk
starting from routine at BB (DC.B 'DOS',0 etc.)
at disk sector 0 (where bootblock reside)
length 2 (self explanatory )
CC -> calculate checksum (fill the second long -> DC.L 0 with the right value)
[if you wonder what the third longword DC.L $370 is, is the disk rootblock, sector 880]

Now if you boot the disk code start from offset $c, the START label.

Enjoy!

[redblade]

http://aminet.net/package/dev/asm/Asm_course There is a Assembler course on aminet. It comes with Asm One and it comes with example code.

Read /examples/BootBlock.S

But it pretty much is as Ross says.

[W4r3DeV1L]

Originally Posted by redblade

http://aminet.net/package/dev/asm/Asm_course There is a Assembler course on aminet. It comes with Asm One and it comes with example code.

Read /examples/BootBlock.S

But it pretty much is as Ross says.

Thanks to to ross and you too!

[W4r3DeV1L]

Hello... remaining in the topic of boot block tutorial, I made tonight another experiment...

Here is the code of a flashing screen waiting for the left mouse button to execute a custom boot block:

bb:
        dc.b 'DOS',0
        dc.l  0
        dc.l  $370
        dcb.b 1024,0

loop:
        move.w #$000, $dff180        
        move.w #$fff, $dff182         
 
checkExit:

        btst #6, $bfe001               ; test LEFT mouse click
        bne loop
        rts 

        lea        Dos(pc),a1          ; string of dos.library into a1 register
        jsr        -96(a6)             ; call FindResident
        tst.l      d0
        beq.s      Err                 ; mod.resid. not found
        movea.l    d0,a0
        movea.l    $16(a0),a0
        moveq      #0,d0
Usc:    rts
Err:    moveq      #-1,d0              ; set error flag
        bra.s      Usc 

Dos:    dc.b 'dos.library',0           ; "dos.library" string

the code seems to work fine if I comment the bb part and execute in the ASM-One, but when it comes to assemble the source and follow the steps mentioned above ( WS, RAM PRT>BB, DISK PTR>0, LENGTH>2, CC ) with the purpose to write the code over a blank disk (removing the comments before bb ) nothing won't start on booting...

do you guys have any clue?

[heavy]

what is the "dcb.b 1024,0" ?
the code is after the boot with that so not copied to disk...
loop should be just after dc.l $370

[ross]

bb:
        dc.b 'DOS',0
        dc.l  0
        dc.l  $370
;        dcb.b 1024,0

loop:
        move.w $dff006, $dff180        
;        move.w #$fff, $dff182         
 
checkExit:

        btst #6, $bfe001               ; test LEFT mouse click
        bne loop
;        rts 

        lea        Dos(pc),a1          ; string of dos.library into a1 register
        jsr        -96(a6)             ; call FindResident
        tst.l      d0
        beq.s      Err                 ; mod.resid. not found
        movea.l    d0,a0
        movea.l    $16(a0),a0
        moveq      #0,d0
Usc:    rts
Err:    moveq      #-1,d0              ; set error flag
        bra.s      Usc 

Dos:    dc.b 'dos.library',0           ; "dos.library" string

[W4r3DeV1L]

Originally Posted by ross

CC -> calculate checksum (fill the second long -> DC.L 0 with the right value)
[if you wonder what the third longword DC.L $370 is, is the disk rootblock, sector 880]

Now if you boot the disk code start from offset $c, the START label.

I do not how to arrange this last step....

[ross]

Nothing to arrange here
You simply need to type CC and ASM-One will generate (and write to inserted ADF, or DF0: in a real machine) the correct checksum on the disk.
Then you can boot the disk and the code in the bootblock starts.

[W4r3DeV1L]

Originally Posted by ross

Then you can boot the disk and the code in the bootblock starts.

ross ... what I doing wrong? .... The disk just created on which I wrote the bb won't boot ...

[ross]

Originally Posted by D4Ni3L3

ross ... what I doing wrong? .... The disk just created on which I wrote the bb won't boot ...

Did you use the version I posted? (post #16)
Notice the commented code.

I assure you that it works.