73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
#include <pic.h>
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#include <common.h>
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#include <string_utils.h>
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#include <serial.h>
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static inline void outb(UINT16 port, UINT8 val) {
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ASM("outb %0, %1" : : "a"(val), "Nd"(port));
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}
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static inline UINT8 inb(UINT16 port) {
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UINT8 ret;
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ASM("inb %1, %0" : "=a"(ret) : "Nd"(port));
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return ret;
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}
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// 慢速 PIC 的小延迟
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static void pic_wait(void) {
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ASM("jmp 1f\n\t1: jmp 1f\n\t1:");
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}
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void pic_init(void) {
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serial_write("PIC: remapping 8259 PIC\n");
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// 保存掩码
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UINT8 mask1 = inb(PIC1_DATA);
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UINT8 mask2 = inb(PIC2_DATA);
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// ICW1：开始初始化，需要 ICW4
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outb(PIC1_CMD, 0x11); pic_wait();
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outb(PIC2_CMD, 0x11); pic_wait();
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// ICW2：向量偏移
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outb(PIC1_DATA, PIC_IRQ_BASE); // IRQ 0-7 → 向量 0x20-0x27
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pic_wait();
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outb(PIC2_DATA, PIC_IRQ_BASE + 8); // IRQ 8-15 → 向量 0x28-0x2F
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pic_wait();
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// ICW3：级联
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outb(PIC1_DATA, 0x04); pic_wait(); // 从片在 IRQ 2
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outb(PIC2_DATA, 0x02); pic_wait(); // 级联标识
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// ICW4：8086 模式
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outb(PIC1_DATA, 0x01); pic_wait();
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outb(PIC2_DATA, 0x01); pic_wait();
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// 恢复掩码
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outb(PIC1_DATA, mask1);
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outb(PIC2_DATA, mask2);
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serial_write("PIC: remapped IRQ 0-7 → 0x20-0x27\n");
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}
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void pic_send_eoi(UINT8 irq) {
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if (irq >= 8) {
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outb(PIC2_CMD, PIC_EOI);
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}
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outb(PIC1_CMD, PIC_EOI);
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}
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void pic_mask_irq(UINT8 irq) {
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UINT16 port = (irq < 8) ? PIC1_DATA : PIC2_DATA;
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UINT8 shift = irq % 8;
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UINT8 mask = inb(port) | (1 << shift);
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outb(port, mask);
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}
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void pic_unmask_irq(UINT8 irq) {
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UINT16 port = (irq < 8) ? PIC1_DATA : PIC2_DATA;
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UINT8 shift = irq % 8;
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UINT8 mask = inb(port) & ~(1 << shift);
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outb(port, mask);
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}
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