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framebuffer driver and a working gdt

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cowmonk 2025-07-19 21:44:14 -07:00
parent 49bf45abc8
commit 4a304f7b63
9 changed files with 761 additions and 40 deletions
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34
kernel/x86/gdt.c
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@ -7,12 +7,12 @@ void
gdt_reload()
{
asm volatile("lgdt %0\n\t"
"push $0x28\n\t"
"lea 1f(%%rip), %%rax\n\t"
"push %%rax\n\t"
"push $0x08\n\t"
"lea 1f(%%rip), %%rax\n\t"
"push %%rax\n\t"
"lretq\n\t"
"1:\n\t"
"mov $0x30, %%eax\n\t"
"mov $0x10, %%eax\n\t"
"mov %%eax, %%ds\n\t"
"mov %%eax, %%es\n\t"
"mov %%eax, %%fs\n\t"
@ -26,44 +26,44 @@ gdt_reload()
void
initGDT()
{
/* null descriptor (0) */
descriptors[0].limit = 0;
// null descriptor (0)
descriptors[0].limit_low = 0;
descriptors[0].base_low = 0;
descriptors[0].base_mid = 0;
descriptors[0].access = 0;
descriptors[0].granularity = 0;
descriptors[0].limit_high_and_flags = 0;
descriptors[0].base_high = 0;
/* kernel code 64 (40) */
descriptors[1].limit = 0;
// kernel code 64 (40)
descriptors[1].limit_low = 0;
descriptors[1].base_low = 0;
descriptors[1].base_mid = 0;
descriptors[1].access = 0b10011010;
descriptors[1].granularity = 0b00100000;
descriptors[1].limit_high_and_flags = 0b00101000;
descriptors[1].base_high = 0;
/* kernel data 64 (48) */
descriptors[2].limit = 0;
// kernel data 64 (48)
descriptors[2].limit_low = 0;
descriptors[2].base_low = 0;
descriptors[2].base_mid = 0;
descriptors[2].access = 0b10010010;
descriptors[2].granularity = 0;
descriptors[2].limit_high_and_flags = 0;
descriptors[2].base_high = 0;
// user code 64 (72)
descriptors[3].limit = 0;
descriptors[3].limit_low = 0;
descriptors[3].base_low = 0;
descriptors[3].base_mid = 0;
descriptors[3].access = 0b11111010;
descriptors[3].granularity = 0b00100000;
descriptors[3].limit_high_and_flags = 0b00101000;
descriptors[3].base_high = 0;
// user data 64. (80)
descriptors[4].limit = 0;
descriptors[4].limit_low = 0;
descriptors[4].base_low = 0;
descriptors[4].base_mid = 0;
descriptors[4].access = 0b11110010;
descriptors[4].granularity = 0;
descriptors[4].limit_high_and_flags = 0;
descriptors[4].base_high = 0;
gdtptr.limit = sizeof(descriptors) - 1;