global PROC_SWITCH
PROC_SWITCH: dw 0

global TIMERVAL
global TIMERVAL_FRAC
TIMERVAL: dd 0
TIMERVAL_FRAC: dd 0
global timerHandler
timerHandler:
push eax
push ds
mov ax, 0x10
mov ds, ax
; Value from PITPgrm
add dword [TIMERVAL_FRAC], 0xfffdb8d0
adc dword [TIMERVAL], 0
mov al, 0x20
out 0x20, al
; Check task switch
movzx eax, word [PROC_SWITCH]
test eax, eax
jnz task_switch
pop ds
pop eax
iret

extern save_current_task_int
task_switch:
mov word [PROC_SWITCH], 0
pop ds
pop eax
call save_current_task_int
iret


global picInit
picInit:
mov al, 0x11  ; initialization sequence
out 0x20, al  ; send to 8259A-1
jmp $+2
jmp $+2
out 0xA0, al  ; and to 8259A-2
jmp $+2
jmp $+2
mov al, 0x20  ; start of hardware ints (0x20)
out 0x21, al
jmp $+2
jmp $+2
mov al, 0x28  ; start of hardware ints 2 (0x28)
out 0xA1, al
jmp $+2
jmp $+2
mov al, 0x04  ; 8259-1 is master
out 0x21, al
jmp $+2
jmp $+2
mov al, 0x02  ; 8259-2 is slave
out 0xA1, al
jmp $+2
jmp $+2
mov al, 0x01  ; 8086 mode for both
out 0x21, al
jmp $+2
jmp $+2
out 0xA1, al
jmp $+2
jmp $+2
mov al, 0xFF  ; all interrupts off for now
out 0x21, al
jmp $+2
jmp $+2
out 0xA1, al
ret