tos.c

Programming for feal strong programmers

#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <conio.h>
#include "tos.h"

void 	Init_And_Protected_Mode_Entry(void);
void 	protected_mode(descriptor far *gdt_ptr);
void 	real_mode(void);
void 	init_gdt_descriptor(descriptor *descr, unsigned long base,
				word limit, unsigned char type);
void vi_print(unsigned int x, unsigned int y, char *s, char attr);
void vi_hello_msg(void);

void  exception_0(void); //{ prg_abort(0); }
void  exception_1(void); //{ prg_abort(1); }
void  exception_2(void); //{ prg_abort(2); }
void  exception_3(void); //{ prg_abort(3); }
void  exception_4(void); //{ prg_abort(4); }
void  exception_5(void); //{ prg_abort(5); }
void  exception_6(void); //{ prg_abort(6); }
void  exception_7(void); //{ prg_abort(7); }
void  exception_8(void); //{ prg_abort(8); }
void  exception_9(void); //{ prg_abort(9); }
void  exception_A(void); //{ prg_abort(0xA); }
void  exception_B(void); //{ prg_abort(0xB); }
void  exception_C(void); //{ prg_abort(0xC); }
void  exception_D(void); //{ prg_abort(0xD); }
void  exception_E(void); //{ prg_abort(0xE); }
void  exception_F(void); //{ prg_abort(0xF); }
void  exception_10(void); //{ prg_abort(0x10); }
void  exception_11(void); //{ prg_abort(0x11); }
void  exception_12(void); //{ prg_abort(0x12); }
void  exception_13(void); //{ prg_abort(0x13); }
void  exception_14(void); //{ prg_abort(0x14); }
void  exception_15(void); //{ prg_abort(0x15); }
void  exception_16(void); //{ prg_abort(0x16); }
void  exception_17(void); //{ prg_abort(0x17); }
void  exception_18(void); //{ prg_abort(0x18); }
void  exception_19(void); //{ prg_abort(0x19); }
void  exception_1A(void); //{ prg_abort(0x1A); }
void  exception_1B(void); //{ prg_abort(0x1B); }
void  exception_1C(void); //{ prg_abort(0x1C); }
void  exception_1D(void); //{ prg_abort(0x1D); }
void  exception_1E(void); //{ prg_abort(0x1E); }
void  exception_1F(void); //{ prg_abort(0x1F); }

void iret0(void);
void iret1(void);

descriptor 	gdt[8];

gate		idt[] = {
	{ (word)&exception_0, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 0
	{ (word)&exception_1, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1
	{ (word)&exception_2, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 2
	{ (word)&exception_3, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 3
	{ (word)&exception_4, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 4
	{ (word)&exception_5, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 5
	{ (word)&exception_6, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 6
	{ (word)&exception_7, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 7
	{ (word)&exception_8, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 8
	{ (word)&exception_9, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 9
	{ (word)&exception_A, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // A
	{ (word)&exception_B, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // B
	{ (word)&exception_C, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // C
	{ (word)&exception_D, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // D
	{ (word)&exception_E, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // E
	{ (word)&exception_F, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // F
	{ (word)&exception_10, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 10
	{ (word)&exception_11, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 11
	{ (word)&exception_12, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 12
	{ (word)&exception_13, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 13
	{ (word)&exception_14, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 14
	{ (word)&exception_15, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 15
	{ (word)&exception_16, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 16
	{ (word)&exception_17, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 17
	{ (word)&exception_18, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 18
	{ (word)&exception_19, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 19
	{ (word)&exception_1A, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1A
	{ (word)&exception_1B, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1B
	{ (word)&exception_1C, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1C
	{ (word)&exception_1D, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1D
	{ (word)&exception_1E, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1E
	{ (word)&exception_1F, CODE_SELECTOR, 0, TYPE_TRAP_GATE, 0 }, // 1F

	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 20
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 21
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 22
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 23
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 24
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 25
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 26
	{ (word)&iret0, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 27

	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 28
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 29
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 2A
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 2B
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 2C
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 2D
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }, // 2E
	{ (word)&iret1, CODE_SELECTOR, 0, TYPE_INTERRUPT_GATE, 0 }  // 2F
};

word y=0;

void main(void) {

	textcolor(BLACK); textbackground(LIGHTGRAY); clrscr();
	Init_And_Protected_Mode_Entry();
	enable_interrupt();

	vi_hello_msg();

	y=3;
	vi_print(0, y++, " 偖璜