68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
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#include "cpu/pic.h"
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#include "cpu/io.h"
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void pic_remap(uint8_t offset1, uint8_t offset2) {
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uint8_t a1, a2;
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a1 = inb(PIC1_DATA); // save masks
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a2 = inb(PIC2_DATA);
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outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4); // starts the initialization sequence (in cascade mode)
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io_wait();
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outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);
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io_wait();
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outb(PIC1_DATA, offset1); // ICW2: Master PIC vector offset
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io_wait();
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outb(PIC2_DATA, offset2); // ICW2: Slave PIC vector offset
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io_wait();
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outb(PIC1_DATA, 4); // ICW3: tell Master PIC that there is a slave PIC at IRQ2 (0000 0100)
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io_wait();
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outb(PIC2_DATA, 2); // ICW3: tell Slave PIC its cascade identity (0000 0010)
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io_wait();
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outb(PIC1_DATA, ICW4_8086);
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io_wait();
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outb(PIC2_DATA, ICW4_8086);
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io_wait();
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outb(PIC1_DATA, a1); // restore saved masks.
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outb(PIC2_DATA, a2);
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}
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void pic_send_eoi(uint8_t irq)
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{
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if(irq >= 8)
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outb(PIC2_COMMAND,PIC_EOI);
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outb(PIC1_COMMAND,PIC_EOI);
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}
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void pic_irq_set_mask(uint8_t IRQline) {
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uint16_t port;
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uint8_t value;
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if(IRQline < 8) {
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port = PIC1_DATA;
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} else {
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port = PIC2_DATA;
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IRQline -= 8;
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}
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value = inb(port) | (1 << IRQline);
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outb(port, value);
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}
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void pic_irq_clear_mask(uint8_t IRQline) {
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uint16_t port;
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uint8_t value;
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if(IRQline < 8) {
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port = PIC1_DATA;
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} else {
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port = PIC2_DATA;
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IRQline -= 8;
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}
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value = inb(port) & ~(1 << IRQline);
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outb(port, value);
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}
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