



        NAM     READCHAR
        
***     Routine name:   READCHAR.
*       Reads one character from terminal.
*
*       Version 1.0
*       hjoel   1987-12-04
*       
*       Exit:   ASCII-code of typed character 
*                 in AccA.
*       All other registers unchanged during operation.
***
        
ACIACR  EQU     $E004           Control-reg-addr of ACIA.
ACIADR  EQU     $E005           Data-reg-addr of ACIA.

        ORG     $BE00
        
READCH  LDA     ACIACR          ACIA contains character?
        RORA
        BCC     READCH
        LDA     ACIADR          Char. from ACIA to AccA.
        RTS
        
        END     READCH
        

        NAM WRITCHAR
        
***     Routine name:   WRITCHAR.
*       Writes one character to terminal.
*
*       Version 1.0
*       hjoel   1987-12-04
*
*       Entry:  ASCII-code of character-to-be-
*                 typed in AccA.
*       AccB changed during operation.
*       All other registers unchanged.
***

ACIACR  EQU     $E004           Control-reg-addr of ACIA.
ACIADR  EQU     $E005           Data-reg-addr of ACIA.

        ORG     $BE10
        
WRITCH  LDB     ACIACR          ACIA ready to receive?
        RORB
        RORB
        BCC     WRITCH
        STA     ACIADR          Char. from AccA to ACIA.
        RTS
        
        END     WRITCH
        

        NAM     WRITESTR
        
***     Routine name:   WRITESTR.
*       Writes a string of characters to terminal.
*       Utilizes subroutine WRITCH (or PUTCHR).
*
*       Version 1.0
*       hjoel   1987-12-10
*
*       Entry:  IX contains beginaddress of con-
*                 secutive memory-cells contain-
*                 ing ASCII-code