diff options
Diffstat (limited to 'src/driver.s')
| -rw-r--r-- | src/driver.s | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/src/driver.s b/src/driver.s index 00e807c..4c2220f 100644 --- a/src/driver.s +++ b/src/driver.s @@ -14,6 +14,10 @@ zp_pal_counter = $31 .endif + ;; Timer for the pause/unpause workflow. + PAUSE_TIMER_VALUE = (HZ / 3) + zp_pause_timer = $32 + ;; Switch from the title screen to the main street. Note that this function ;; is to be called with the PPU disabled. If that's not the case, then it ;; will set the proper values to disable it on the next `nmi` call and set @@ -77,7 +81,57 @@ @load_player: jsr Player::init + ;; Initialize pause timer. + lda #0 + sta zp_pause_timer + @game: + ;; Check if the player is toggling the `pause` state. + lda #(Joypad::BUTTON_START | Joypad::BUTTON_SELECT) + and Joypad::zp_buttons1 + beq @skip_pause_handling + + ;; What does the timer say, is the player allowed to do it? + lda zp_pause_timer + bne @skip_pause_handling + + ;; The timer is zero and the player asked to pause, let's reset the + ;; timer. + lda #PAUSE_TIMER_VALUE + sta zp_pause_timer + + ;; Pause vs unpause. + lda #%00001000 + and Globals::zp_flags + bne @unpause + + ;; Pause: set the flag and skip the update. + lda #%00001000 + ora Globals::zp_flags + sta Globals::zp_flags + rts + + @unpause: + ;; Unset the flag and go to update. + lda #%11110111 + and Globals::zp_flags + sta Globals::zp_flags + bne @do_update + + @skip_pause_handling: + ;; Decrement the pause timer if it's not in a zero value. + lda zp_pause_timer + beq @pause_check + dec zp_pause_timer + + @pause_check: + ;; Are we paused? If so return before updating. + lda #%00001000 + and Globals::zp_flags + beq @do_update + rts + + @do_update: JAL Player::update .endproc |