global int_clock_handler
[extern task_switch_next]

CLOCK_COUNTER:
    db 0x00

[bits 32]
int_clock_handler:
 
 ;Notice there is no IRQ number or error code - we don't need them

 inc byte [CLOCK_COUNTER]
 
 cmp byte  [CLOCK_COUNTER], 0x10

 jne skip_clock

 mov byte [CLOCK_COUNTER], 0x00

 pusha          ;Push all standard registers

 push esp       ;Push pointer to all the stuff we just pushed

 call task_switch_next ;Call C code
 
 mov esp, eax   ;Replace the stack with what the C code gave us

 popa           ;Put the standard registers back
 
 skip_clock:

 mov al, 0x20   ;Port number AND command number to Acknowledge IRQ
 out 0x20, al     ;Acknowledge IRQ, so we keep getting interrupts

 ;We didn't push an error code or IRQ number, so we don't have to edit esp now
 
 iret           ;Interrupt-Return