emailler/drivers/a2input.s

.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 --