lcd.zsm

 ORG 0100h
 LD A,56          ; initialize 16x2, 8-bit mode
 CALL cmd_output
 LD A,12          ; display on, cursor off
 CALL cmd_output
 LD A,6           ; auto increment cursor
 CALL cmd_output
 LD A,1           ; clear display
 CALL cmd_output
 LD A,128         ; put cursor at start of line 1
 CALL cmd_output
 LD B,16          ; process (up to) 16 characters
 CALL input
 LD C,2           ; BDOS: print character
 LD E,13          ; print CR
 CALL 5
 LD C,2           ; BDOS: print character
 LD E,10          ; print LF
 CALL 5
 LD A,192         ; put cursor at start of line 2
 CALL cmd_output
 LD B,16          ; process (up to) 16 characters
 CALL input
 RET
input
 PUSH BC          ; save B register count
 LD C,1           ; BDOS: input/echo character
 CALL 5
 POP BC
 CP 10
 JR Z,crlf
 CP 13
 JR Z,crlf
 CALL char_output
 JP next
crlf
 LD B,1           ; skip rest of line on CR/LF
next
 DJNZ input
 RET
cmd_output
 OUT (70h),A      ; set to command port address
 JP busy
char_output
 OUT (71h),A      ; set to character port address
busy
 IN A,(70h)       ; set to command port address
 RLCA
 JR C,busy
 RET