.title TerminalIO Perform Terminal IO

;
; Author:	Rodrick A. Eldridge
;		104 Computer Science
;		Iowa State University
;		Ames, Iowa 50011
;		(515) 294-5659
;
; Created:	April 1986
;
; Modification History:
;
; Description:	This module contains a set of routines for performing
;		single character and line-oriented terminal I/O
;
;		The routines that are available are:
;
;			routine name	parameters
;			------------	----------
;
;			TerminalIo
;
;			Read		char
;			ReadString	string
;			ReadLn
;			ReadAgain
;
;			Write		char
;			WriteString	string
;			WriteLn
;

external module TerminalIo	<>

external module Read		<char>
external module ReadString	<descr>
external module ReadLn		<>
external module ReadAgain	<>

external module Write		<char>
external module WriteString	<descr>
external module WriteLn		<>

const
  $dscdef		; descriptor definitions
  $rabdef		; record access block definitons
  max_length=512


global module TerminalIo -
  psect=terminal_io

var
  input_fab:		$fab	fac=get,fnm=<SYS$INPUT>
  input_rab:		$rab	fab=input_fab,-
				ubf=input_buffer,-
				usz=max_length

  output_fab:		$fab	fac=put,fnm=<SYS$OUTPUT>
  output_rab:		$rab	fab=output_fab,-
				rbf=output_buffer,-
				rsz=max_length

  input_descr:		descr	.blkb max_length input_buffer  *
  output_descr:		descr	.blkb max_length output_buffer *

  input_position:	.word	0
  output_position:	.word	0

  open_flag:		.word	0
  cr_lf:		.byte	13,10

begin

  ;
  ; Initialize the terminal i/o routines
  ;

  $open		fab=input_fab
  $connect	rab=input_rab

  $open		fab=output_fab
  $connect	rab=output_rab

  movw #max_length+1,input_position
  clrw output_position

  movw #1,open_flag
  return

end


global module Read <char> -
  psect=terminal_io

begin

  ;
  ; Read single character from the input device
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  if <cmpw input_position,input_descr> gtr then
    Readln
  end

  movzwl input_position,r1
  movb   input_buffer[r1],@read.char(ap)
  incw   input_position

  return

end


global module ReadString <descr> -
  psect=terminal_io -
  mask=<r6,r7>

begin

  ;
  ; Read a string from the input device
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  $get	rab=input_rab				; read string

  moval input_rab,r1
  movw	rab$w_rsz(r1),input_descr		; actual length read

  pushr r0
  movq  @ReadString.descr(ap),r6		; r6=string length,r7=address
  movc5 #max_length,input_buffer,#^a/ /,r6,(r7)
  popr  r0

  return

end


global module ReadLn -
  psect=terminal_io

begin

  ;
  ; Read a string from the input device and position input pointer
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  $get	rab=input_rab				; read string

  moval input_rab,r1
  movw	rab$w_rsz(r1),input_descr		; actual length read

  clrw input_position

  return

end


global module ReadAgain -
  psect=terminal_io

begin

  ;
  ; Reset position input pointer
  ;

  if <tstw open_flag> eql then
    TerminalIo
    Readln
  end

  clrw input_position

  return

end


global module Write <char> -
  psect=terminal_io

begin

  ;
  ; Write a character to the output device
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  movzwl output_position,r1
  movb   @Write.char(ap),output_buffer[r1]
  incw   output_position

  return

end


global module WriteString <descr> -
  psect=terminal_io -
  mask=<r6,r7>

begin

  ;
  ; Write a string to the output device
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  movq  @WriteString.descr(ap),r6		; r6=string length, r7=buffer
  movc5 r6,(r7),#^a/ /,#max_length,output_buffer
  movw  r6,output_position

  WriteLn

  return

end
    

global module WriteLn -
  psect=terminal_io

begin

  ;
  ; Write a carriage control and line feed to the output device and
  ; optionally, write a string to the output device
  ;

  if <tstw open_flag> eql then
    TerminalIo
  end

  $rab_store	rab=output_rab,-
		rbf=cr_lf,-
		rsz=#2

  $put rab=output_rab

  if <movzwl output_position,r6> neq then

    $rab_store	rab=output_rab,-
		rbf=output_buffer,-
		rsz=r6

    $put rab=output_rab				; write string

    clrw output_position

  end

  return

end

.end