Added get_filtered_input for the ATARI.

The code is totally(!) untested but added for now to just make programs link that refer to it.

drivers/Makefile

@@ -47,6 +47,7 @@ ATROBJS=\
 	atrtimer.o \
 	atrkernal.o \
 	atrinput.o \
+	atrfilteredinput.o \
 	atrcharconv.o
 
 VIC20OBJS=\

drivers/atrfilteredinput.s

@@ -0,0 +1,164 @@
+.export get_filtered_input
+.export filter_text
+.export filter_ip
+.export filter_dns
+.export filter_url
+.export filter_number
+
+.import get_key
+.import print_a
+
+.include "zeropage.inc"
+.include "../inc/common.i"
+
+allowed_ptr = ptr1
+
+
+.code
+
+; 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 #$00
+  sta INPUT_Y
+
+  ; Wait for a character.
+@input_get:
+  jsr get_key
+  sta LASTCHAR
+
+  cmp #$fe                      ; Delete
+  beq @delete
+
+  cmp #$9b                      ; 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 #$88
+  jsr print_a
+
+  ; Wait for next char
+  jmp @input_get
+
+; =================================================
+; Some example filters
+; =================================================
+filter_text:
+  .byte ",!#'()* "
+filter_url:
+  .byte ":/%&?+$"
+filter_dns:
+  .byte "-AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz"
+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 a2filteredinput.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 --