Here is a solution for part of the SPO600 64-bit Assembly Language Lab but implemented in 6502 Assembly language for use with the 6502 Emulator:
; ROM routines
define SCINIT $ff81
define CHROUT $ffd2
START:
JSR SCINIT ; Initialize and clear the screen
LDX #$00 ; Loop index (0-9)
LINE:
TXA ; Put loop index into A
CLC
ADC #$30 ; Add $30 (ASCII '0')
STA MSG_DIGIT ; Store into the string
LDY #$00 ; Character number to print
CHARACTER:
LDA MSG,Y ; Get a character
BEQ DONE ; Done if it's NULL
JSR CHROUT ; Print character
INY ; Increment char number
JMP CHARACTER ; Process next character
DONE:
INX ; Increment loop index
CPX #10 ; Is it 10?
BNE LINE ; If not, print next line
BRK ; Stop
MSG:
DCB "L","o","o","p",$20
MSG_DIGIT:
DCB "#",$0D,$00
; Note that MSG_DIGIT is a position in
; the middle of the message - not a
; separate message.