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update cx16 keyhandler example to r43 keyboard changes

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Irmen de Jong 2023-05-14 23:33:57 +02:00
parent 70cd4fedbe
commit 415c599310
1 changed files with 12 additions and 34 deletions
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46
examples/cx16/keyboardhandler.p8
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@ -9,17 +9,16 @@ main {
sub start() {
txt.print("ps2 custom key handler test - press keys! esc to quit!\n")
txt.print("custom key handler test - press keys! esc to quit!\n")
sys.set_irqd()
uword old_keyhdl = cx16.KEYHDL
cx16.KEYHDL = &keyboard_scancode_handler
sys.clear_irqd()
bool escape_pressed
while not escape_pressed {
handle_keyboard_event()
while handle_keyboard_event() {
}
sys.set_irqd()
cx16.KEYHDL = old_keyhdl
sys.clear_irqd()
@ -30,70 +29,49 @@ main {
; so that they won't get overwritten with initialization values every time.
; The assembly keyboard handler will set these, prog8 will read them.
bool @shared keyhdl_event ; is there a keyboard event to handle?
ubyte @shared keyhdl_prefix
ubyte @shared keyhdl_scancode
ubyte @shared keyhdl_updown
sub handle_keyboard_event() {
sub handle_keyboard_event() -> bool {
; Potentially handle keyboard event.
; Note that we do this from the program's main loop instead of
; the actual keyboard handler routine itself.
; The reason for this is documented below in the handler assembly routine.
if not keyhdl_event
return
return true
keyhdl_event = false
txt.print_ubhex(keyhdl_prefix, true)
txt.chrout(':')
txt.print_ubhex(keyhdl_scancode, true)
txt.spc()
if keyhdl_updown
if keyhdl_scancode & $80
txt.chrout('u')
else
txt.chrout('d')
txt.nl()
if keyhdl_prefix==0 and keyhdl_scancode==119 and keyhdl_updown {
; escape was pressed! exit back to basic
main.start.escape_pressed = true
}
return keyhdl_scancode!=$6e ; escape breaks the loop
}
asmsub keyboard_scancode_handler() {
; NOTE that the keyboard handler is an asm subroutine.
; Unfortunately is it not possible to use prog8 code or calls here,
; because the X register gets overwritten here (to store the prefix byte)
; and prog8 uses the X register internally (for the evaluation stack).
; because the X register gets overwritten here by the kernal.
; Pog8 uses the X register internally (for the software eval stack).
; So it is unsafe to call prog8 code from here because the evaluation stack pointer
; will be invalid which produces undefined results.
; So, instead, we store the various keyboard event bytes and signal
; the main prog8 program that a keyboard event has occurred.
; It then processes it independently from the assembly code here.
;
; Unfortunately this also means you cannot decide from that prog8 code
; Unfortunately this also means you cannot decide easily from that prog8 code
; if the keyboard press should be consumed/ignored or put into the keyboard queue
; (this is controlled by returning 0 or 1 in register A here)
;
; see:
; https://github.com/X16Community/x16-docs/blob/master/X16%20Reference%20-%2002%20-%20Editor.md#custom-keyboard-scancode-handler
%asm {{
php
pha
phx
stz keyhdl_updown
bcc +
inc keyhdl_updown
+ stx keyhdl_prefix
sta keyhdl_scancode
lda #1
sta keyhdl_event
; we can do additional stuff here and decide if we want to
; consume the key event or not (A=0 or A!=0)
plx
pla
lda #0 ;By setting A=0 we will remove this key event for now
tax
plp
lda #0 ; By setting A=0 we will eat this key event. leave A unchanged to pass it through.
rts
}}
}