File : drivers/a2input.s

functions

check whether the escape key is being pressed
inputs: none
outputs: sec if escape pressed, clear otherwise

cribbed from http://codebase64.org/doku.php?id=base:robust_string_input
======================================================================
Input a string and store it in GOTINPUT, terminated with a null byte.
AX is a pointer to the allowed list of characters, null-terminated.
set AX to $0000 for no filter on input
max # of chars in y returns num of chars entered in y.
======================================================================
 Main entry

use Apple 2 monitor ROM function to read from keyboard
inputs: none
outputs: A contains ASCII code of key pressed

inputs: none
outputs: A contains ASCII value of key just pressed (0 if no key pressed)

process inbound ip packets while waiting for a keypress

constants

implementation

.export get_key  
.export check_for_abort_key
.export get_filtered_input
.export filter_text
.export filter_ip
.export filter_dns
.export filter_number
.export get_key_ip65
.export get_key_if_available

.import ip65_process
.import print_a
.import print_hex

.importzp copy_src

.include "../inc/common.i"

allowed_ptr=copy_src ;reuse zero page
.code
;use Apple 2 monitor ROM function to read from keyboard
;inputs: none
;outputs: A contains ASCII code of key pressed
get_key:
  ;lda #$a0
  ;lda #$20
  ;ldy #$24 ;KEYIN assumes Y is loaded with column
  ;jmp $fd1b
  jmp $fd0c

;inputs: none
;outputs: A contains ASCII value of key just pressed (0 if no key pressed)
get_key_if_available:
  bit $c000 ;Key down?
  bmi get_key
  lda #0
  rts



  
;check whether the escape key is being pressed
;inputs: none
;outputs: sec if escape pressed, clear otherwise
check_for_abort_key:
lda $c000 ;current key pressed
cmp #$9B
bne :+
bit $c010 ;clear the keyboard strobe
sec
rts
:
clc
rts

;process inbound ip packets while waiting for a keypress
get_key_ip65:
  jsr ip65_process
  bit $c000 ;Key down?
  bpl get_key_ip65
  jmp get_key



;cribbed from http://codebase64.org/doku.php?id=base:robust_string_input
;======================================================================
;Input a string and store it in GOTINPUT, terminated with a null byte.
;AX is a pointer to the allowed list of characters, null-terminated.
;set AX to $0000 for no filter on input
;max # of chars in y returns num of chars entered in y.
;======================================================================


; Main entry
get_filtered_input:
  sty MAXCHARS
  stax temp_allowed

  ;Zero characters received.
  lda #$00
  sta INPUT_Y

;Wait for a character.
@input_get:
  jsr get_key_ip65  
  ;convert to standard ASCII by turning off high bit
  and #$7f
  sta LASTCHAR
  cmp #$08               ;Delete
  beq @delete

  cmp #$0d               ;Return
  beq @input_done

  ;End reached?
  lda INPUT_Y
  cmp MAXCHARS
  beq @input_get

  ;Check the allowed list of characters.
  ldax temp_allowed
  stax allowed_ptr  ;since we are reusing this zero page, it may not stil be the same value since last time!
  ldy #$00
  lda allowed_ptr+1     ;was the input filter point nul?
  beq @input_ok
@check_allowed:
  lda (allowed_ptr),y           ;Overwritten
  beq @input_get         ;Reached end of list (0)

  cmp LASTCHAR
  beq @input_ok           ;Match found

  ;Not end or match, keep checking
  iny
  jmp @check_allowed

@input_ok:
  lda LASTCHAR          ;Get the char back
  ldy INPUT_Y
  sta GOTINPUT,y        ;Add it to string

  inc INPUT_Y           ;Next character
  jsr  print_a
  ;Not yet.
  jmp @input_get

@input_done:
   ldy INPUT_Y
   beq  @no_input
   lda #$00
   sta GOTINPUT,y   ;Zero-terminate
   clc
   ldax #GOTINPUT
   rts
@no_input:
   sec
   rts
; Delete last character.
@delete:
  ;First, check if we're at the beginning.  If so, just exit.
  lda INPUT_Y
  bne @delete_ok
  jmp @input_get

  ;At least one character entered.
@delete_ok:
  ;Move pointer back.
  dec INPUT_Y

  ;Store a zero over top of last character, just in case no other characters are entered.
  ldy INPUT_Y
  lda #$00
  sta GOTINPUT,y

  ;Print the backspace char
  lda #$88
  jsr print_a

  ;Print the a space
  lda #$a0
  jsr print_a

  ;Print the backspace char
  lda #$88
  jsr print_a

  ;Wait for next char
  jmp @input_get


;=================================================
;Some example filters
;=================================================

filter_text:
  .byte ",+!#$%&'()* "
filter_dns:
.byte "-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
filter_ip:
.byte "."
filter_number: 
.byte "1234567890",0

;=================================================
.bss
temp_allowed: .res 2
MAXCHARS: .res 1
LASTCHAR: .res 1
INPUT_Y: .res 1  
GOTINPUT: .res 40



;-- LICENSE FOR a2input.s --
; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
; 
; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
; 
; The Original Code is ip65.
; 
; The Initial Developer of the Original Code is Jonno Downes,
; jonno@jamtronix.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Jonno Downes. All Rights Reserved.  
; -- LICENSE END --