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<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><link rel="stylesheet" type="text/css" href="ca65-doc-style.css"/></head><body><a href="ref_index.html"><h1>ip65 technical reference</h1></a><h1>File : drivers/a2input.s</h1><h2 id="functions">functions</h2><table><tr><th>function</th><th>description</th></tr><tr><td id="check_for_abort_key">check_for_abort_key</td><td><pre>check whether the escape key is being pressed
inputs: none
outputs: sec if escape pressed, clear otherwise </pre></td></tr><tr><td id="get_filtered_input">get_filtered_input</td><td><pre>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 $0000 for no filter on input
max # of chars in y returns num of chars entered in y.
======================================================================
Main entry </pre></td></tr><tr><td id="get_key">get_key</td><td><pre>use Apple 2 monitor ROM function to read from keyboard
inputs: none
outputs: A contains ASCII code of key pressed </pre></td></tr><tr><td id="get_key_if_available">get_key_if_available</td><td><pre>inputs: none
outputs: A contains ASCII value of key just pressed (0 if no key pressed) </pre></td></tr><tr><td id="get_key_ip65">get_key_ip65</td><td><pre>process inbound ip packets while waiting for a keypress </pre></td></tr></table><h2 id="constants">constants</h2><table><tr><th>constants</th><th>description</th><th>value</th></tr><tr><td id="filter_dns">filter_dns</td><td></td><td>"-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
</td></tr><tr><td id="filter_ip">filter_ip</td><td></td><td>"."
</td></tr><tr><td id="filter_number">filter_number</td><td></td><td>"1234567890",0
</td></tr><tr><td id="filter_text">filter_text</td><td>=================================================
Some example filters
================================================= </td><td>",+!#$%&'()* "
</td></tr></table><h2>implementation</h2><pre id="code">.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 --
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