matos/arch/x86/irq_pit.S
2020-04-27 23:45:38 +02:00

39 lines
901 B
ArmAsm

.file "irq_pit.S"
.text
.extern switchKthread
.globl pit_handler
.type pit_handler, @function
pit_handler: // already got eflags, cs and eip on stack thanks to CPU
pushl $0 // err_code esp+12+8*4=44
pushal // (general reg) esp+12
subl $2, %esp // (alignment) esp+10
pushw %ss // esp+8
pushw %ds // esp+6
pushw %es // esp+4
pushw %fs // esp+2
pushw %gs // esp
/* Send EOI to PIC */
movb $0x20, %al
outb %al, $0x20
pushl %esp
call pitIrqHandler
movl %eax,%esp
/* Restore the CPU context */
popw %gs
popw %fs
popw %es
popw %ds
popw %ss
addl $2,%esp
popal
addl $4, %esp /* Ignore "error code" */
/* This restores the eflags, the cs and the eip registers */
iret /* equivalent to: popfl ; ret */