emailler/client/drivers/c64inputs.s

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.export get_key
.export get_filtered_input
.export filter_text
.export filter_ip
.export filter_dns
.export check_for_abort_key
.export get_key_if_available
.importzp copy_src
.include "../inc/common.i"
.code
allowed_ptr=copy_src ;reuse zero page
;use C64 Kernel ROM function to read a key
;inputs: none
;outputs: A contains ASCII value of key just pressed
get_key:
jsr $ffe4
beq get_key
rts
;use C64 Kernel ROM function to read a key
;inputs: none
;outputs: A contains ASCII value of key just pressed (0 if no key pressed)
get_key_if_available=$ffe4
;check whether the RUN/STOP key is being pressed
;inputs: none
;outputs: sec if RUN/STOP pressed, clear otherwise
check_for_abort_key:
lda $cb ;current key pressed
cmp #$3F
bne @not_abort
@flush_loop:
jsr $ffe4
bne @flush_loop
lda $cb ;current key pressed
cmp #$3F
beq @flush_loop
sec
rts
@not_abort:
clc
rts
;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.
;x:a is a pointer to the allowed list of characters, null-terminated.
;max # of chars in y returns num of chars entered in y.
;======================================================================
; Main entry
get_filtered_input:
sty MAXCHARS
stax allowed_ptr
;Zero characters received.
lda #$00
sta INPUT_Y
;Wait for a character.
INPUT_GET:
jsr get_key
sta LASTCHAR
cmp #$14 ;Delete
beq DELETE
cmp #$0d ;Return
beq INPUT_DONE
;Check the allowed list of characters.
ldy #$00
CHECKALLOWED:
lda (allowed_ptr),y ;Overwritten
beq INPUT_GET ;Reached end of list (0)
cmp LASTCHAR
beq INPUTOK ;Match found
;Not end or match, keep checking
iny
jmp CHECKALLOWED
INPUTOK:
lda LASTCHAR ;Get the char back
ldy INPUT_Y
sta GOTINPUT,y ;Add it to string
jsr $ffd2 ;Print it
inc INPUT_Y ;Next character
;End reached?
lda INPUT_Y
cmp MAXCHARS
beq INPUT_DONE
;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 delete char
lda #$14
jsr $ffd2
;Wait for next char
jmp INPUT_GET
;=================================================
;Some example filters
;=================================================
filter_text:
.byte ",+!#$%&'()* "
filter_dns:
.byte " -ABCDEFGHIJKLMNOPQRSTUVWXYZ"
filter_ip:
.byte "1234567890.",0
;=================================================
.bss
MAXCHARS: .res 1
LASTCHAR: .res 1
INPUT_Y: .res 1
GOTINPUT: .res 40