CLS for CP/M

README.md

CLS

Transient commands in Assembly for clearing the screen on CP/M-80 and CP/M-86 with an ANSI/VT100 terminal.

Usage

Execute CLS with no arguments from the command prompt:

A>CLS

cls.a86

; Clear the screen.
;
; Runs on CP/M-86 with an ANSI/VT100 terminal.


WRITESTR            equ     09h             ; BDOS function write string
TERMCPM             equ     00h             ; BDOS function terminate program


                    cseg

                    mov     cl, WRITESTR
                    lea     dx, clshome
                    int     224

                    mov     cl, TERMCPM
                    int     224


                    dseg

                    org     100h

; ANSI escapes:
;    clear screen      : ESC [ 2 J
;    go to screen home : ESC [ H
clshome             db      1bh, '[2J', 1bh, '[H$'

                    end

cls.asm

; Clear the screen.
;
; Runs on CP/M-80 with an ANSI/VT100 terminal.

TPA                 equ     100h
BDOS                equ     05h
WRITESTR            equ     09h             ; Write string


                    org     TPA

                    mvi     c, WRITESTR
                    lxi     d, clshome
                    call    BDOS

                    ret


; ANSI escapes:
;   clear screen      : ESC [ 2 J
;   go to screen home : ESC [ H
clshome:            db      1bh, '[2J', 1bh, '[H$'

                    end