CP/M example that prints command line arguments

CmdArgs_PrintChar.asm

; CP/M example that prints command line arguments
    .org $100 ; standard CP/M offset

    ld hl,$0080  ; command line arguments address
    ld a, (hl)
    or a
    ret z
    inc hl        
Loop:    
    inc hl      
    ld a, (hl)
    or a
    ret z
    ld e, a
    ld c, $02    ; routine $02
    push hl
    call $0005   ; call BDOS vector
    pop hl
    jr Loop
End:
    ret  

CmdArgs_PrintString.asm

; CP/M example that prints command line arguments
    .org $100 ; standard CP/M offset

    ld hl,$0080  ; command line arguments address
    ld a,(hl)    ; get arguments length
    or a         ; check length
    ret z        ; zero length, exit
    xor b        ; set zero high byte
    ld c, a      ; low byte contains length
    inc hl       ; +1, skip length
    ld d, h      ; copy address 
    ld e, l      ; to de
    add hl,bc    ; move to end of string
    inc de       ; +1, skip preceeding space
    ld (hl), '$' ; change 0 to '$'
    ld c, $09    ; print string BDOS routine
    push hl      ; store hl
    call $0005   ; call BDOS vector
    pop hl       ; restore hl
    xor (hl)     ; change '$' back to 0
    ret