I wrote this out in my senior economics class. The notes are sometimes cryptic, and there were bugs. I tried to fix some as I typed it up though. These are just the parts that I feel like trying to understand.
Code:
Code:
;EventQueue structure
;.dw address, message; the message can be an address, a value, or nothing at all
EventHandlerHalt:;this section was added 5/21/10
halt
EventHandler:
ld a,(EventQueueSize)
or a
;jp z,EventHandler;/upon rereading, I should halt to save battery
jp z,EventHandlerHalt
ld hl,(EventQueue+2)
ex de,hl
ld hl,ReturnToHere
push hl
ld hl,(EventQueue)
;call hl;/not a valid instruction
jp (hl);will return to ReturnToHere
ReturnToHere:;added later because call hl is not real
ld hl,(EventQueue+4)
ld de,(EventQueue)
ld bc,(EventQueueSize)
ldir
ld a,(EventQueueSize)
sub 4
ld (EventQueueSize),a
jp EventHandler
ScheduleEvent:
push af
ld c,4;b=0 /that's what the notes said
add hl,bc
ld de, EventQueue
ld a,(EventQueueSize)
push hl
ld l,a \ ld h,0
add hl,de
ex de,hl,hl
pop hl; hl=addr, bc = 4 /I can only assume hl is the address of the event
add a,4
jp c,EQoverflowHandler
ldir
ld c,8
pop af
ret
;TaskScheduleSize
;.db size
;TaskSchedule
;.dw timer, maxtimer, address, message
TaskManager:;although not marked in the notes, this is called from the interrupt
ld a,(ScheduleSize)
ld hl,TaskSchedule
ld b,0; added later to fix the bc enigma
TaskManagerLoop:;just called it loop in the notes
ld de,1;to begin with, the notes are cryptic, and it's barely legible on this line. it was added as an afterthought and I have no idea what it is
;ld bc,8 ;the notes are cryptic about this one. The event scheduler that it calls seems to need b to be 0
;I think I may have figured out what the bc is, so I'm commenting out the line to fix the bug
dec (hl)
push hl;added later to fix obvious bug
call z,ScheduleEvent
pop hl;added to match the push
sub 8;
ret z
ld bc,8 ; this fixes that bc enigma
add hl,bc
jp TaskManagerLoop
ScheduleEventHL: ;schedule event for code other than the task manager
EQoverflowHandler:
;remove all tasks in the removable task list
;remove all events in the removable event list
;move tasks together (condense them)
;move events together
;if recovery was successful, schedule the recovery event and return
;if recovery was a failure, try to preserve data in RAM then display a panic screen, then soft reset and try to determine the cause
TI smote the Beta Testers for their insolence and rested. SynThesIs 14
He doesn't have to wake up, you know. I have a laser, and we have a garbage disposal. - Pintsize
What does the GUI say about his fill level? IT'S OVER 9000!!!
He doesn't have to wake up, you know. I have a laser, and we have a garbage disposal. - Pintsize
What does the GUI say about his fill level? IT'S OVER 9000!!! 
