The Tandy Color Computer from the 1980’s uses a Motorola 6809 microprocessor.
If you want to get started with assembly language on the Tandy Coco this is a small program to get started with.
You can use the EDATASM program cartridge to enter and assemble the executable program on a physical Coco machine or you can use an emulator with the following steps:
- Create a disk image with MAME imgtool
imgtool create coco_jvc_rsdos hello.dsk
- Cross compile with lwasm
lwasm -9bl -p cd -oHELLO.BIN hello.asm
- Put the BIN file output on the disk image with imgtool
imgtool put coco_jvc_rsdos hello.dsk HELLO.BIN HELLO.BIN
- Run on the VCC Tandy Coco emulator.

Once assembled the program can be run from BASIC with the following command if you have saved the BIN file to disk.
LOADM"HELLO"
EXEC
* FILENAME: HELLO.ASM
* CLEARS SCREEN, PRINTS "HELLO WORLD" AND
* WAITS FOR KEYPRESS
ORG $2A00
START
* CREATE NEW STACK
STS OLDS
LDS #24+STK
* CLEAR THE SCREEN
JSR $A928
* PRINT THE MESSAGE
LDX #MESG
LOOP LDA ,X+
BEQ KEY
* CALL CHROUT
JSR [$A002]
BRA LOOP
* WAIT FOR KEYPRESS
KEY JSR [$A000]
BEQ KEY
* RESTORE STACK
LDS OLDS
* RETURN TO BASIC
DONE RTS
* DATA
MESG FCC /HELLO WORLD/
FCB 13
FCB 0
OLDS RMB 2
STK RMW 12
END START
