emailler/client/drivers/a2input.s

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.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