luciaos/kernel.c
2022-09-19 16:06:01 -05:00

132 lines
3.4 KiB
C

#include <stdint.h>
#include "print.h"
#include "interrupt.h"
#include "tss.h"
typedef unsigned short word;
char check_apic() {
uint32_t eax, ebx, ecx, edx;
asm("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) : "a"(1));
return (edx & (1 << 9)) != 0;
}
char check_sse() {
uint32_t eax, ebx, ecx, edx;
asm("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) : "a"(1));
return (edx & (1 << 25)) != 0;
}
void enable_sse() {
asm volatile(
"mov %%cr0, %%eax\n"
"and $0xFFFB, %%ax\n"
"or $0x2, %%ax\n"
"mov %%eax, %%cr0\n"
"mov %%cr4, %%eax\n"
"or $0x600, %%ax\n"
"mov %%eax, %%cr4\n"
: : : "%eax"
);
}
void print_flags() {
uint32_t flags;
asm volatile("pushfd\npop %%eax":"=a"(flags));
printDword(flags, 0xB8000 + (160*4) + 50);
}
void print_cr0() {
uint32_t reg;
asm volatile("mov %%cr0, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50);
}
void print_cr3() {
uint32_t reg;
asm volatile("mov %%cr3, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50 + 8*2 + 2);
}
void print_cr4() {
uint32_t reg;
asm volatile("mov %%cr4, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50 + 8*4 + 4);
}
__attribute((__no_caller_saved_registers__))
extern void enter_v86(uint32_t ss, uint32_t esp, uint32_t cs, uint32_t eip);
extern void v86Test();
extern void v86GfxMode();
__attribute((__no_caller_saved_registers__))
extern char *jmp_usermode_test();
/*
Real Mode Accessible (First MB)
00000 - 00400 IVT (1kB)
00400 - 01000 Unused (3kB)
01000 - 04000 Paging (12kB)
04000 - 07C00 Free (15kB)
07C00 - 08000 Boot (512B)
08000 - 20000 Kernel Code (96kB)
20000 - 20080 TSS (128B)
20080 - 22080 TSS IOMAP (8kB)
22080 - 22400 Unused (896B)
22400 - 23000 Free (3kB)
23000 - 80000 Free (372kB)
80000 - 90000 Real Mode Stack (64kB)
90000 - A0000 Free (64kB)
A0000 - FFFFF BIOS Area (384kB)
Protected Only (1MB+)
100000 - 300000 Free (2mB)
300000 - 310000 Task Stack (64kB)
310000 - 320000 Interrupt Stack (64kB)
320000 - 400000 Kernel Stack (896kB)
400000 - 500000 Usermode Stack (1mB)
*/
void start() {
word *vga_text = (word *)0xb8000;
char h[] = "LuciaOS";
for (int i = 0; i < sizeof(h); i++)
*(char *)&vga_text[i] = h[i];
uint32_t o;
asm("mov %%esp, %%eax" : "=a"(o) : :);
printDword(o, (uint16_t *)&vga_text[80]);
asm("mov %%ebp, %%eax" : "=a"(o) : :);
printDword(o, (uint16_t *)&vga_text[160]);
//char c[] = "APIC support: ";
//char apic;
//printByte(apic = check_apic(), (short*)&vga_text[80*3 + sizeof(c) - 1]);
//for (int i = 0; i < sizeof(c); i++)
// *(char *)&vga_text[i+(80*3)] = c[i];
//if (!apic) return;
char sse_str[] = "SSE support: ";
char sse;
printByte(sse = check_sse(), (uint16_t*)&vga_text[80*4 + sizeof(sse_str) - 1]);
for (int i = 0; i < sizeof(sse_str); i++)
*(char *)&vga_text[i+(80*4)] = sse_str[i];
if (!sse) return;
enable_sse();
// edit
setup_interrupts();
setup_tss();
print_flags();
print_cr0();
print_cr3();
print_cr4();
FARPTR v86_entry = i386LinearToFp(v86Test);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry));
v86_entry = i386LinearToFp(v86GfxMode);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry));
char *vga = jmp_usermode_test();
//asm ("xchgw %bx, %bx");
for (int i = 0; i < 320; i++) {
vga[i] = i;
}
}