mirror of https://github.com/tailix/libkernaux.git
46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
#include <stdint.h>
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#include <stddef.h>
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#include <kernaux/console.h>
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#include "stivale2.h"
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static void poweroff();
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uint8_t stack[8192];
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// We will now write a helper function which will allow us to scan for tags
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// that we want FROM the bootloader (structure tags).
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void *stivale2_get_tag(struct stivale2_struct *stivale2_struct, uint64_t id) {
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struct stivale2_tag *current_tag = (void *)stivale2_struct->tags;
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for (;;) {
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// If the tag pointer is NULL (end of linked list), we did not find
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// the tag. Return NULL to signal this.
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if (current_tag == NULL) {
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return NULL;
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}
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// Check whether the identifier matches. If it does, return a pointer
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// to the matching tag.
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if (current_tag->identifier == id) {
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return current_tag;
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}
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// Get a pointer to the next tag in the linked list and repeat.
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current_tag = (void *)current_tag->next;
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}
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}
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// The following will be our kernel's entry point.
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void _start(struct stivale2_struct *stivale2_struct __attribute__((unused))) {
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kernaux_console_puts("Hello, World!");
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poweroff();
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}
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void poweroff()
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{
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const uint16_t port = 0x604;
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const uint16_t value = 0x2000;
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__asm__ volatile("outw %1, %0" : : "dN" (port), "a" (value));
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}
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