xyou
f1a2a110d7
Add the current OS source tree, build scripts, system image layout, and development notes covering DMA page allocation, e1000 bring-up, net API dispatch, and DHCP work in progress.
223 lines
6.1 KiB
C
223 lines
6.1 KiB
C
#include <utsm/idt.h>
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#include <utsm/log.h>
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#include <utsm/types.h>
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/* IDT gate descriptor (64-bit) */
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typedef struct __attribute__((packed)) {
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u16 offset_low;
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u16 selector;
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u8 ist;
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u8 type_attr;
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u16 offset_mid;
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u32 offset_high;
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u32 reserved;
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} idt_entry;
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/* IDT register */
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typedef struct __attribute__((packed)) {
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u16 limit;
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u64 base;
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} idt_ptr;
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#define IDT_ENTRIES 256
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static idt_entry g_idt[IDT_ENTRIES] __attribute__((aligned(16)));
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#define PIC1_CMD 0x20
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#define PIC1_DATA 0x21
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#define PIC2_CMD 0xA0
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#define PIC2_DATA 0xA1
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#define ICW1_ICW4 0x01
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#define ICW1_INIT 0x10
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/* assembly stub declarations */
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extern void isr_stub_0(void);
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extern void isr_stub_1(void);
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extern void isr_stub_2(void);
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extern void isr_stub_3(void);
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extern void isr_stub_4(void);
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extern void isr_stub_5(void);
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extern void isr_stub_6(void);
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extern void isr_stub_7(void);
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extern void isr_stub_8(void);
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extern void isr_stub_9(void);
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extern void isr_stub_10(void);
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extern void isr_stub_11(void);
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extern void isr_stub_12(void);
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extern void isr_stub_13(void);
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extern void isr_stub_14(void);
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extern void isr_stub_15(void);
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extern void isr_stub_16(void);
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extern void isr_stub_17(void);
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extern void isr_stub_18(void);
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extern void isr_stub_19(void);
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extern void isr_stub_20(void);
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extern void isr_stub_21(void);
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extern void isr_stub_22(void);
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extern void isr_stub_23(void);
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extern void isr_stub_24(void);
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extern void isr_stub_25(void);
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extern void isr_stub_26(void);
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extern void isr_stub_27(void);
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extern void isr_stub_28(void);
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extern void isr_stub_29(void);
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extern void isr_stub_30(void);
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extern void isr_stub_31(void);
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extern void isr_stub_32(void);
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extern void isr_stub_33(void);
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extern void isr_stub_34(void);
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extern void isr_stub_35(void);
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extern void isr_stub_36(void);
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extern void isr_stub_37(void);
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extern void isr_stub_38(void);
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extern void isr_stub_39(void);
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extern void isr_stub_40(void);
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extern void isr_stub_41(void);
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extern void isr_stub_42(void);
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extern void isr_stub_43(void);
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extern void isr_stub_44(void);
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extern void isr_stub_45(void);
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extern void isr_stub_46(void);
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extern void isr_stub_47(void);
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static void *g_isr_table[] = {
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isr_stub_0, isr_stub_1, isr_stub_2, isr_stub_3,
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isr_stub_4, isr_stub_5, isr_stub_6, isr_stub_7,
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isr_stub_8, isr_stub_9, isr_stub_10, isr_stub_11,
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isr_stub_12, isr_stub_13, isr_stub_14, isr_stub_15,
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isr_stub_16, isr_stub_17, isr_stub_18, isr_stub_19,
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isr_stub_20, isr_stub_21, isr_stub_22, isr_stub_23,
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isr_stub_24, isr_stub_25, isr_stub_26, isr_stub_27,
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isr_stub_28, isr_stub_29, isr_stub_30, isr_stub_31,
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isr_stub_32, isr_stub_33, isr_stub_34, isr_stub_35,
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isr_stub_36, isr_stub_37, isr_stub_38, isr_stub_39,
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isr_stub_40, isr_stub_41, isr_stub_42, isr_stub_43,
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isr_stub_44, isr_stub_45, isr_stub_46, isr_stub_47,
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};
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static void outb(u16 port, u8 value) {
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__asm__ volatile ("outb %0, %1" :: "a"(value), "Nd"(port));
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}
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static u8 inb(u16 port) {
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u8 value;
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__asm__ volatile ("inb %1, %0" : "=a"(value) : "Nd"(port));
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return value;
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}
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static void io_wait(void) {
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outb(0x80, 0);
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}
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static void pic_remap(void) {
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/* save masks */
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u8 m1 = inb(PIC1_DATA);
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u8 m2 = inb(PIC2_DATA);
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/* ICW1: start init + ICW4 */
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outb(PIC1_CMD, ICW1_INIT | ICW1_ICW4);
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io_wait();
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outb(PIC2_CMD, ICW1_INIT | ICW1_ICW4);
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io_wait();
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/* ICW2: vector offsets */
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outb(PIC1_DATA, 0x20); /* master: vectors 0x20-0x27 */
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io_wait();
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outb(PIC2_DATA, 0x28); /* slave: vectors 0x28-0x2F */
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io_wait();
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/* ICW3: master/slave wiring */
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outb(PIC1_DATA, 0x04); /* master: IRQ2 → slave */
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io_wait();
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outb(PIC2_DATA, 0x02); /* slave: cascade identity */
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io_wait();
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/* ICW4: 8086 mode */
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outb(PIC1_DATA, 0x01);
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io_wait();
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outb(PIC2_DATA, 0x01);
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io_wait();
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/* restore masks: mask all except IRQ1 (keyboard) */
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outb(PIC1_DATA, 0xFD); /* 1111_1101: enable IRQ0 (timer) and IRQ1 (kb) */
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outb(PIC2_DATA, 0xFF); /* mask all slave */
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}
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static void idt_set_entry(u8 vector, void *handler, u8 ist, u8 type) {
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u64 addr = (u64)handler;
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g_idt[vector].offset_low = (u16)(addr & 0xffff);
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g_idt[vector].selector = 0x08; /* kernel code segment (from GDT) */
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g_idt[vector].ist = ist;
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g_idt[vector].type_attr = type;
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g_idt[vector].offset_mid = (u16)((addr >> 16) & 0xffff);
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g_idt[vector].offset_high = (u32)(addr >> 32);
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g_idt[vector].reserved = 0;
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}
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void idt_init(void) {
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log_info("[IDT] init begin");
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for (u16 i = 0; i < 48; i++) {
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idt_set_entry((u8)i, g_isr_table[i], 0, 0x8E); /* present, ring0, 64-bit interrupt gate */
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}
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/* fill unused entries with null */
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for (u16 i = 48; i < IDT_ENTRIES; i++) {
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idt_set_entry((u8)i, 0, 0, 0);
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}
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idt_ptr idtr;
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idtr.limit = (u16)(sizeof(g_idt) - 1);
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idtr.base = (u64)&g_idt;
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__asm__ volatile ("lidt %0" :: "m"(idtr));
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pic_remap();
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log_info("[IDT] PIC remapped (master=0x20 slave=0x28)");
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__asm__ volatile ("sti");
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log_info("[IDT] interrupts enabled");
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log_info("[IDT] init ok");
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}
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/* IRQ handler table */
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static irq_handler_t g_irq_handlers[16];
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int irq_register(u8 irq, irq_handler_t handler) {
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if (irq >= 16) return -1;
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g_irq_handlers[irq] = handler;
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return 0;
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}
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/* Stack frame pushed by isr_common in idt.S */
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typedef struct {
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u64 r11, r10, r9, r8, rax, rcx, rdx, rsi, rdi;
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u64 vector;
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u64 error_code;
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u64 rip, cs, rflags;
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} isr_frame;
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void idt_handler(isr_frame *frame) {
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if (frame->vector < 32) {
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log_error("[IDT] exception");
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log_hex64("[IDT] vector=", frame->vector);
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log_hex64("[IDT] err=", frame->error_code);
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log_hex64("[IDT] rip=", frame->rip);
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for (;;) { __asm__ volatile ("cli; hlt"); }
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}
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if (frame->vector >= 32 && frame->vector <= 47) {
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u8 irq = (u8)(frame->vector - 0x20);
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/* call registered handler */
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if (irq < 16 && g_irq_handlers[irq]) {
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int suppress_eoi = g_irq_handlers[irq](irq);
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if (suppress_eoi) return;
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}
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/* send EOI */
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if (frame->vector >= 0x28) {
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outb(PIC2_CMD, 0x20);
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}
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outb(PIC1_CMD, 0x20);
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}
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}
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