; ***************************************************************************
; Hello world example showing how to use the TAP format and our simple
; BASIC boot loader that has been recompiled into TAP format.
;
; Author: Peter Mount, Area51.dev & Contributors
; URL: https://area51.dev/sinclair/asm/loaders/tap/
; ***************************************************************************

; for zasm we need to tell it to generate a tap file
#target tap

; code_start will be where our code will be compiled to
code_start equ 24000

; ***************************************************************************
; Header block containing the block name and the size of the machine code
; ***************************************************************************

#code CODE_HEADER,0,17,0
        defb    3                       ; Indicates binary data
        defb    "helloworld"            ; the block name, 10 bytes long
        defw    code_end-code_start     ; length of data block which follows
        defw    code_start              ; default location for the data
        defw    0                       ; unused

; ***************************************************************************
; Data block containing a actual machine code program:
;
; Here we simply print the "Hello World!" message to the screen.
; ***************************************************************************

#code CODE_DATA, code_start,*,0xff

; This is the code_start address 24000 0x5DC0
        ld      a,2                     ; set print channel to Screen:
        call    0x1601

        ld      hl,msg                  ; message start address
loop:   ld      a,(hl)                  ; get next byte
        and     a                       ; check for null
        ret     z                       ; stop when we get a null
        inc     hl                      ; move to next character
        rst     2                       ; print the character
        jr      loop                    ; jump back to the loop

msg:    dm      13, "Hello World!", 13, 0

; End of code marker needed for the CODE_HEADER
code_end:

; Anything after this point will not be included in the .tap file