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#1 2023-08-30 08:24:30

Implite
Member
Registered: 2023-08-28
Posts: 3
AndroidChrome 115.0

Z80 coleco assembly - table driven assembler

These are some code examples I'm trying to learn from and a way how to assemble your own code.

if anyone is interested in trying to make a comunity built game for coleco in assembly language please contact me. I have been trying to learn from 8-bit Mill's code and have made some interesting discoveries looking over his code.

Extract tasm to the folder you have your source file in
assemble using:
tasm filename.z80 -80 -b
rename using:
ren filename.obj filename.rom

dosbox download:
https://www.dosbox.com/download.php?main=1

tasm download:
https://www.ticalc.org/pub/dos/asm/

MSX/Coleco Sprite & Tile Set Editor:
https://www.electricadventures.net/Pages/Category/24


Ill be demonstrating how to code in z80 assembly for colecovision and adam.
Starting from baby steps as im just starting to learn myself

Everything you need to get started  is posted here and should be easy to copy and paste and assemble

Added later 10 min 52 s:
Thanks to https://8bitmilligames.com/ for helping me with this code!

;cartridge header and title example

	.org $8000
	
	
TitleControl    .dw     055AAh

	.dw 0,0,0,0, start
	.dw 0,0,0,0,0,0,0,0,0,0,0

	retn
	.text "YOUR NAME/HELLO WORLD!/2022"
start:
     jp $0000
	 .end

title and screen with hello world

.org $8000
	
	
TitleControl    .dw     055AAh

	.dw 0,0,0,0, start
	.dw 0,0,0,0,0,0,0,0,0,0,0

	retn
	.text "YOUR NAME/HELLO WORLD!/2022"
start:
        call $1f85 ; cv bios : mode_1
	call $1fd6 ; cv bios : turn off sound
	
	;clear video ram
	ld a,0
	ld hl,0
	ld de,$4000
	call $1f82 ; cv bios : fill_vram
	
	;color white (f) on blue (4)
	ld a,$f4
	ld hl,$2000
	ld de,32
	call $1f82 ; cv bios : fill_vram
	call $1f7f ; cv bios : load_ascii
	
	; print "helloworld!"
	ld de,$1800
	ld hl,helloworld
	ld bc,12
	call $1fdf ; cv bios :write_vram
	ld de,$1820
	ld hl,nextline
	ld bc,28
	call $1fdf ; cv bios :write_vram
	ld de,$1840
	ld hl,helloworld
	ld bc,12
	call $1fdf ; cv bios :write_vram
	
	; screen on
	ld bc,$01c2
	call $1fd9 ; cv bios :write_register
	
	; infinite loop 
end:
    jp end
	.end
	
helloworld:
   .db "HELLO WORLD!"
nextline:
   .db "this is the hello world demo"

Added later 14 min 50 s:

Last edited by Implite (2023-09-09 12:06:41)

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#2 2023-09-08 21:34:41

Implite
Member
Registered: 2023-08-28
Posts: 3
AndroidChrome 115.0

Re: Z80 coleco assembly - table driven assembler

Some improved Hello World code plus gives the user the ability to move the text anywhere on the screen:

; COLECOVISION - HELLO WORLD!
; By Daniel Bienvenu (newcoleco) and implite,2023
;tasm syntax

; BIOS (SOME) ENTRY POINTS
CALC_OFFSET: .equ $08c0
LOAD_ASCII: .equ $1f7f
FILL_VRAM: .equ $1f82
MODE_1: .equ $1f85
PUT_VRAM: .equ $1fbe
TURN_OFF_SOUND: .equ $1fd6
WRITE_REGISTER: .equ $1fd9
READ_REGISTER: .equ $1fdc
WRITE_VRAM: .equ $1fdf

; VRAM DEFAULT TABLES
VRAM_PATTERN: .equ $0000
VRAM_NAME: .equ $1800
VRAM_SPRATTR: .equ $1B00
VRAM_COLOR: .equ $2000
VRAM_SPRGEN: .equ $3800
    
    .org $8000
    
    ; HEADER
    .dw $55AA ; use $AA55 to avoid the default CV title screen
    .dw 0,0,0,0
    .dw Start	
rst_8:
    reti
    nop
rst_10:
    reti
    nop
rst_18:
    reti
    nop
rst_20:
    reti
    nop
rst_28:
    reti
    nop
rst_30:
    reti
    nop
rst_38:
    reti
    nop
    jp Nmi
    
TitleScreen    .text   "TEXT DEMO/HELLO WORLD!/2023"

    ; PROGRAM
Start:
    im 1
    
    ; CLEAR VIDEO MEMORY
    ld  hl,$0000
    ld  de,$4000
    xor a
    call FILL_VRAM
    
    ; INIT DEFAULT SCREEN GRAPHIC MODE 1
    call MODE_1

    ; NO SOUND
    call TURN_OFF_SOUND

    ; DEFAULT FONT TO VIDEO MEMORY
    call LOAD_ASCII
    
    ; COLOR WHITE ON BLUE BACKGROUND
    ld  hl,VRAM_COLOR ; COLOR TABLE
    ld  de,32
    ld  a,$f4 ; WHITE ON BLUE
    call FILL_VRAM

    ; PRINT "HELLO WORLD!" CENTERED AT THE TOP OF THE SCREEN
    ; FORMULA = (32 CHARS PER LINE - 12 CHARS TO OUTPUT) / 2 = 10    
    call Calculated_Offset ;Static_Offset ; or use Calculated_Offset
    call Write_HelloWorld ; or use Put_HelloWorld but make sure to not add VRAM NAME TABLE with the Offset
    
    ; 16KB VIDEO MEMORY, 16x16 NORMAL SPRITES, AND TURN ON SCREEN
    ld  bc,$01c2 ; $01e2 ; = AND ENABLE NMI EXECUTION
    call WRITE_REGISTER
    
TheEnd:
    jp  TheEnd
	.end
    
HelloWorld:
    .db "HELLO WORLD!"

Static_Offset:
    ld  de,VRAM_NAME+330 ; VRAM NAME TABLE + OFFSET
    ret 

Calculated_Offset:
    ld  d,10 ; LINE = 0
    ld  e,10 ; COLUMN = 10
    call CALC_OFFSET ; OFFSET = 32 * D + E
    ld  hl,VRAM_NAME
    add hl,de
    ex  de,hl
    ret
    
Write_HelloWorld:
    ld  hl,HelloWorld
    ld  bc,12 ; COUNT
    jp WRITE_VRAM

Put_HelloWorld:
    ld  a,2 ; ID#2 = VRAM NAME TABLE
    ld  hl,HelloWorld
    ld  iy,12 ; COUNT
    jp PUT_VRAM

Nmi:
    ; RANDOM COLOR ON BLACK BACKGROUND
    ld  hl,VRAM_COLOR ; COLOR TABLE
    ld  de,32
    ld  a,r ; REFRESH MEMORY STATE USED AS A RANDOM VALUE
    and $f0 ; BLACK BACKGROUND
    call FILL_VRAM

    ; ABSOLUTELY NEEDED
    call READ_REGISTER
    retn

Last edited by Implite (2023-09-08 21:37:29)

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#3 2023-09-09 07:05:16

Milli
Administrator
Registered: 2023-07-16
Posts: 9
iPhoneSafari 16.6

Re: Z80 coleco assembly - table driven assembler

Very nice - but understand those VRAM equates are not set in stone, that just happens to be the ColecoVision BIOS defaults.

Implite wrote:

Some improved Hello World code plus gives the user the ability to move the text anywhere on the screen:

; COLECOVISION - HELLO WORLD!
; By Daniel Bienvenu (newcoleco) and implite,2023
;tasm syntax

; BIOS (SOME) ENTRY POINTS
CALC_OFFSET: .equ $08c0
LOAD_ASCII: .equ $1f7f
FILL_VRAM: .equ $1f82
MODE_1: .equ $1f85
PUT_VRAM: .equ $1fbe
TURN_OFF_SOUND: .equ $1fd6
WRITE_REGISTER: .equ $1fd9
READ_REGISTER: .equ $1fdc
WRITE_VRAM: .equ $1fdf

; VRAM DEFAULT TABLES
VRAM_PATTERN: .equ $0000
VRAM_NAME: .equ $1800
VRAM_SPRATTR: .equ $1B00
VRAM_COLOR: .equ $2000
VRAM_SPRGEN: .equ $3800
    
    .org $8000
    
    ; HEADER
    .dw $55AA ; use $AA55 to avoid the default CV title screen
    .dw 0,0,0,0
    .dw Start	
rst_8:
    reti
    nop
rst_10:
    reti
    nop
rst_18:
    reti
    nop
rst_20:
    reti
    nop
rst_28:
    reti
    nop
rst_30:
    reti
    nop
rst_38:
    reti
    nop
    jp Nmi
    
TitleScreen    .text   "TEXT DEMO/HELLO WORLD!/2023"

    ; PROGRAM
Start:
    im 1
    
    ; CLEAR VIDEO MEMORY
    ld  hl,$0000
    ld  de,$4000
    xor a
    call FILL_VRAM
    
    ; INIT DEFAULT SCREEN GRAPHIC MODE 1
    call MODE_1

    ; NO SOUND
    call TURN_OFF_SOUND

    ; DEFAULT FONT TO VIDEO MEMORY
    call LOAD_ASCII
    
    ; COLOR WHITE ON BLUE BACKGROUND
    ld  hl,VRAM_COLOR ; COLOR TABLE
    ld  de,32
    ld  a,$f4 ; WHITE ON BLUE
    call FILL_VRAM

    ; PRINT "HELLO WORLD!" CENTERED AT THE TOP OF THE SCREEN
    ; FORMULA = (32 CHARS PER LINE - 12 CHARS TO OUTPUT) / 2 = 10    
    call Calculated_Offset ;Static_Offset ; or use Calculated_Offset
    call Write_HelloWorld ; or use Put_HelloWorld but make sure to not add VRAM NAME TABLE with the Offset
    
    ; 16KB VIDEO MEMORY, 16x16 NORMAL SPRITES, AND TURN ON SCREEN
    ld  bc,$01c2 ; $01e2 ; = AND ENABLE NMI EXECUTION
    call WRITE_REGISTER
    
TheEnd:
    jp  TheEnd
	.end
    
HelloWorld:
    .db "HELLO WORLD!"

Static_Offset:
    ld  de,VRAM_NAME+330 ; VRAM NAME TABLE + OFFSET
    ret 

Calculated_Offset:
    ld  d,10 ; LINE = 0
    ld  e,10 ; COLUMN = 10
    call CALC_OFFSET ; OFFSET = 32 * D + E
    ld  hl,VRAM_NAME
    add hl,de
    ex  de,hl
    ret
    
Write_HelloWorld:
    ld  hl,HelloWorld
    ld  bc,12 ; COUNT
    jp WRITE_VRAM

Put_HelloWorld:
    ld  a,2 ; ID#2 = VRAM NAME TABLE
    ld  hl,HelloWorld
    ld  iy,12 ; COUNT
    jp PUT_VRAM

Nmi:
    ; RANDOM COLOR ON BLACK BACKGROUND
    ld  hl,VRAM_COLOR ; COLOR TABLE
    ld  de,32
    ld  a,r ; REFRESH MEMORY STATE USED AS A RANDOM VALUE
    and $f0 ; BLACK BACKGROUND
    call FILL_VRAM

    ; ABSOLUTELY NEEDED
    call READ_REGISTER
    retn

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#4 2023-09-09 11:35:17

Implite
Member
Registered: 2023-08-28
Posts: 3
AndroidChrome 115.0

Re: Z80 coleco assembly - table driven assembler

Milli wrote:

Very nice - but understand those VRAM equates are not set in stone, that just happens to be the ColecoVision BIOS defaults.

Thanks however I cannot take full credit for making this. Newcoleco made this I just changed some values and syntax however if someone copies and paste this code the the result should be this:

16942767813261944292016290678741.jpg

Side note:
Also displays the title text.

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