6502 Assembler

m_a_d_s does *._a_t_r

; Build *.ATR
;
; This program shows how one can compile 6502 source into
; a valid *.ATR image file ( => an bootable disk Image for Atari 8- Bit computers)
; using the MADS Assembler. You can use it as a framework for your own projects.
;
; Why?
;
; I was asking myself, how one could start *.XEX image files on the real machine.
; *.XEX files are Atari DOS 2.x compatible binary files. Since the SIO2USB
; interface - that I use - can not start such files I had to find a work around.
;
; The easiest way for me was to tell the MADS Assembler not to write an Atari DOS binary
; and put the *.ATR image header at the start. After the image file header, which 
; convinces SIO2USB that it is loading a valid *.ATR, folows meta data representing
; a valid Atari boot srctor.
;
; After compiling change the filename from *.XEX to *.ATR. That's it :-)  
 
;
; BF 7.9.2014
 
 
	opt h-				; Omit DOS file header
	
	org $a800			; Your choice :-)
 
;
; *.ATR Image File Header
;
	
	.word $0296			; Magic Number : Start of *.ATR image file header=> 16 Bytes in total
	.word 128*720/16	; Image Size / 16 = 92160 Bytes
	.byte 128			; Sector size low
	.byte 0				; Sector size high
	.byte 0				; Extented Para????
	.byte 0				; 8  to 16, unused
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	
;
; Atari Boot Sektor
;
	org $0700
ram	
	.byte 0				; Always!
	.byte 10			; # of sectors to read
	.word ram			; Store sectors at thet adress.
	.word init			; Start code that begins here

;
; #2 Boot continious
;
 
start					
	ldy #0				; Do something........
	lda #103
	sta (88),y
	
	clc					; Everything is OK!
	rts					; Back to OS => Jump to Dos- Vector => main
	
;
; #1: Init routine
; 

init
	lda #<main			; Init Dos- Vector
	sta $a				
	lda #>main
	sta $b
	
	rts					; Return to OS
;
; #3 Main
;

main
 	ldy #39				; To something........
	lda #105
	sta (88),y
en
	jmp en
endofcode
	.byte 0

MADS does *.ATR

; Build *.ATR
;
; This program shows how one can compile 6502 source into
; a valid *.ATR image file ( => an bootable disk Image for Atari 8- Bit computers)
; using the MADS Assembler. You can use it as a framework for your own projects.
;
; Why?
;
; I was asking myself, how one could start *.XEX image files on the real machine.
; *.XEX files are Atari DOS 2.x compatible binary files. Since the SIO2USB
; interface - that I use - can not start such files I had to find a work around.
;
; The easiest way for me was to tell the MADS Assembler not to write an Atari DOS binary
; and put the *.ATR image header at the start. After the image file header, which 
; convinces SIO2USB that it is loading a valid *.ATR, folows meta data representing
; a valid Atari boot srctor.
;
; After compiling change the filename from *.XEX to *.ATR. That's it :-)  
 
;
; BF 7.9.2014
 
 
	opt h-				; Omit DOS file header
	
	org $a800			; Your choice :-)
 
;
; *.ATR Image File Header
;
	
	.word $0296			; Magic Number : Start of *.ATR image file header=> 16 Bytes in total
	.word 128*720/16	        ; Image Size / 16 = 92160 Bytes
	.byte 128			; Sector size low
	.byte 0				; Sector size high
	.byte 0				; Extented Para????
	.byte 0				; 8  to 16, unused
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	.byte 0
	
;
; Atari Boot Sektor
;
	org $0700
ram	
	.byte 0				; Always!
	.byte 10			; # of sectors to read
	.word ram			; Store sectors at that adress.
	.word init			; Start code that begins here

;
; #2 Boot continious
;
 
start					
	ldy #0				; Do something........
	lda #103
	sta (88),y
	
	clc					; Everything is OK!
	rts					; Back to OS => Jump to Dos- Vector => main
	
;
; #1: Init routine
; 

init
	lda #<main			        ; Init Dos- Vector
	sta $a				
	lda #>main
	sta $b
	
	rts					; Return to OS
;
; #3 Main
;

main
 	ldy #39				        ; To something........
	lda #105
	sta (88),y
en
	jmp en
endofcode
	.byte 0

VBI_Demo.asm

; Vertical Blank Interrupt Demo
;
; BF 2018

	org $a800
	
	ldy #<vbi		;Start adress of VBI
	ldx #>vbi
	lda #6			;= Immediate VBI
	jsr $e45c		; Start VBI!
infinite
	jmp infinite

;
; The VBI routine
;
; Executed, every time the electron beam returns to to top left corner
; of the crt......
;	

vbi	
	lda $14
	ldy #0
	sta (88),y
	
	jmp $e45f		; Leave VBI