LaunchBank14_210.pbp

; This patch changes behaviour of the Back button
; in watchfaces:
; If you (from any watchface)
; press Back button and shortly after then any button,
; it will launch an app installed in bank N,
; where N is a button ID (Back=0, Up=1, Select=2, Down=3).
; I.e. you can turn on backlight with Back button alone,
; launch app0 with Back-Back,
; launch app1 with Back-Up, app2 with Back-Select
; and app3 with Back-Down.
; You may choose which app is installed in which bank
; by uninstalling and reinstalling apps in desired order.
; This is greatly simplified since 2.0 app with Locker.
;
; This version works with 2.1.0, any HW version.
#ver 210 219

; just a simple mask to find named proc
08 4b 10 b5 04 46 18 68 08 e0 {
	proc app_manager_get_bank_info 
}

1f b5 04 46 20 b9 09 48 {
	proc app_manager_launch 
}

37 B5 0D 46 04 46 0D F1 02 01 01 A8 {
	proc time_ms
}

; This matches some SerialConsole-related proc
; which references memory address used for serial console read buffer.
; We will use this address to store timer value.
08 B5 05 4B 1B 78 13 B9  3E 20 ?4 03 4B
00 22 C3 F8 84 20 08 BD  ?4 @ {
	val counter_ptr
}

; This matches beginning of watchface_button_handler proc.
; We replace "CMP R3, 5 // BEQ ret" with our code:
38 B5 03 78 @ 05 2b 29 d0  00 79 02 28 04 d0 03 28 {
	B.W my_code
	global continue ; and will return here if we wouldn't like to consume button :)
}

; and append our code
{
	proc my_code
	CMP R3, 5 ; reexecute replaced code
	BEQ ret; we don't need button_up events

	MOV R5, R0 ; save R0 as we want to use it

	; check if this is first or subsequent btn press
	LDR R0, counter
	LDR R4, [R0] ; get old counter value
	MOV R1, 0
	BL time_ms
	LDR R2, counter
	LDR R1, [R2]
	MOV.W R3, 1000
	MUL R1, R3 ; convert seconds to millis
	ADD R1, R0 ; now R1 contains full timestamp

	; check current button
	LDRB R0, [R5,4]
	CBNZ R0, notupdate

	; update counter only if this was Back btn
	STR R1, [R2] ; update counter value

	; check diff
	notupdate:
	SUB R1, R1, R4 ; calculate diff
	MOV.W R3, 500 ; delay in millis
	CMP R1, R3
	BHI cont ; if diff is too large, pass this button to original proc

	; now launch app: get its info -
	; R0 holds button id, which we use as bank id,
	; i.e. launch app from bank 0..3 depending on button
	BL app_manager_get_bank_info
	CBZ R0, ret ; if no such app, just return
	LDR R0, [R0,0xC] ; get app id from bank info
	BL app_manager_launch

	ret: ; terminate proc
	db 38 BD ; POP {R3-R5,PC}

	cont: ; return to original proc for it to handle this button
	MOV R0, R5 ; restore R0
	B.W continue

	; ---------------------------

	; data block
	ALIGN 4
	counter: ; memory location for click counter. 
	DCD counter_ptr ; this should be a serial console's read buffer
}