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;; IRQ0 HANDLER (TIMER INTERRUPT) ;;
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align 32
irq0:
save_ring3_context
mov ax, os_data
mov ds, ax
mov es, ax
inc dword [timer_ticks]
mov eax, [timer_ticks]
call playNote ; <<<--- Speaker driver
cmp eax,[next_usage_update]
jb .nocounter
add eax,100
mov [next_usage_update],eax
call updatecputimes
.nocounter:
cmp [0xffff], byte 1
jne .change_task
mov al,0x20 ; send End Of Interrupt signal
mov dx,0x20
out dx,al
mov [0xffff], byte 0
restore_ring3_context
iret
.change_task:
call update_counters
call find_next_task
mov ecx, eax
mov al,0x20 ; send End Of Interrupt signal
mov dx,0x20
out dx,al
test ecx, ecx ; if there is only one running process
jnz .return
call do_change_task
.return:
restore_ring3_context
iret
align 4
change_task:
pushfd
cli
pushad
call update_counters
call find_next_task
test eax, eax ; the same task -> skip switch
jnz .return
mov [0xffff],byte 1
call do_change_task
.return:
popad
popfd
ret
uglobal
align 4
far_jump:
.offs dd ?
.sel dw ?
context_counter dd ? ;noname & halyavin
next_usage_update dd ?
timer_ticks dd ?
prev_slot dd ?
event_sched dd ?
endg
update_counters:
mov edi, [0x3010]
mov ebx, [edi+0x18] ; time stamp counter add
call _rdtsc
sub eax, ebx
add eax, [edi+0x14] ; counter sum
mov [edi+0x14], eax
ret
; Find next task to execute
; result: ebx = number of the selected task
; [0xffff] = 1 if the task is the same
find_next_task:
mov ebx,[0x3000]
mov [prev_slot], ebx
.waiting_for_termination:
.waiting_for_reuse:
.waiting_for_event:
.suspended:
cmp ebx, [0x3004]
jb @f
mov edi, 0x3000
xor ebx, ebx
@@:
add edi,0x20
inc ebx
mov al, byte [edi+0xA]
test al, al
jz .found
cmp al, 1
jz .suspended
cmp al, 2
jz .suspended
cmp al, 3
je .waiting_for_termination
cmp al, 4
je .waiting_for_termination
cmp al, 9
je .waiting_for_reuse
mov [0x3000],ebx
mov [0x3010],edi
cmp al, 5
jne .noevents
call get_event_for_app
test eax, eax
jz .waiting_for_event
mov [event_sched], eax
mov [edi+0xA], byte 0
.noevents:
.found:
mov [0x3000],ebx
mov [0x3010],edi
call _rdtsc
mov [edi+0x18],eax
xor eax, eax
cmp ebx, [prev_slot]
sete al
ret
; in: ebx = TSS selector index
do_change_task:
shl ebx, 3
xor eax, eax
add ebx, tss0
mov [far_jump.sel], bx ; selector
mov [far_jump.offs], eax ; offset
jmp pword [far_jump]
inc [context_counter] ;noname & halyavin
ret
align 4
updatecputimes:
mov eax,[idleuse]
mov [idleusesec],eax
mov [idleuse],dword 0
mov ecx, [0x3004]
mov edi, 0x3020
.newupdate:
mov ebx,[edi+0x14]
mov [edi+0x1c],ebx
mov [edi+0x14],dword 0
add edi,0x20
dec ecx
jnz .newupdate
ret