65 lines
1.7 KiB
C
65 lines
1.7 KiB
C
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#include "pic.h"
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#include "asm.h"
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#include "mem.h"
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struct IDT_REGISTER IDTR={
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90*8,
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0
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};
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/// Bridge between IDT and functions call
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asm (
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"PIC_IRQ_DEFAULT:"
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"movb $0x20, %al \n\t"
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"outb %al, $0x20 \n\t"
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"iret \n\t"
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"PIC_IRQ_PRINT: \n\t"
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"call _8042_keypress \n\t"
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"movb $0x20, %al \n\t"
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"outb %al, $0x20 \n\t"
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"iret \n\t"
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);
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extern u32 PIC_IRQ_DEFAULT,PIC_IRQ_PRINT;
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void pic_enable_interrupt(){
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// Map first default 32 entries
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for(int i=0;i<90;i++){
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pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_DEFAULT,IDT_TYPE_1});
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if(i==32)
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pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_PRINT,IDT_TYPE_1});
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}
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// Now configure 8952A
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// ICW1: Initialisation
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outbj(0x20,0x11); // Master
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outbj(0xA0,0x11); // Slave
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// ICW2: Map IRQ index to entry into the IDT
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outbj(0x21,0x20); // Start interrupt at offset 0x20 in IDT (index 32)
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outbj(0xA1,0x50); // Start interrupt at offset 0x50 in IDT (index 80)
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// ICW3: Indicate the connection between master and slave
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outbj(0x21,0x02); // Slave connected to pin 2
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outbj(0xA1,0x01); // Indicate pin id to the slave (2-1)
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// ICW4: Operating mode
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outbj(0x21,0x01); // Default operating mode
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outbj(0xA1,0x01); // Default operating mode
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asm("lidtl (IDTR)");
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asm("sti");
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}
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void pic_add_idt_entry(IDT_ENTRY entry){
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static int cur_offset=0;
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int descriptor[2];
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descriptor[0]=entry.offset & 0xFFFF | entry.segment << 16;
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descriptor[1]=entry.type & 0xFFFF | entry.offset & 0xFFFF0000;
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memcpy((void*)descriptor, (void *)(IDTR.base+cur_offset),8);
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cur_offset+=8;
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}
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