初始化GDT和IDT

05_day/bootpack.c

@@ -1,3 +1,5 @@
+#include <stdio.h>
+
 void io_hlt(void);
 void io_cli(void);
 void io_out8(int port, int data);
@@ -10,7 +12,8 @@ void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, i
 void init_screen(char *vram, int x, int y);
 void putfont8(char *vram, int xsize, int x, int y, char c, char *font);
 void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s);
-
+void init_mouse_cursor8(char *mouse, char bc);
+void putblock8_8(char *vram, int vxsize, int pxsize, int pysize, int px0, int py0, char *buf, int bxsize);
 
 #define COL8_000000		0
 #define COL8_FF0000		1
@@ -35,17 +38,46 @@ struct BOOTINFO {
 	char *vram;
 };
 
+struct SEGMENT_DESCRIPTOR {
+	short limit_low, base_low;
+	char base_mid, access_right;
+	char limit_high, base_high;
+};
+
+struct GATE_DESCRIPTOR {
+	short offset_low, selector;
+	char dw_count, access_right;
+	short offset_high;
+};
+
+void init_gdtidt(void);
+void set_segmdesc(struct SEGMENT_DESCRIPTOR *sd, unsigned int limit, int base, int ar);
+void set_gatedesc(struct GATE_DESCRIPTOR *gd, int offset, int selector, int ar);
+void load_gdtr(int limit, int addr);
+void load_idtr(int limit, int addr);
+
 void HariMain(void)
 {
 	struct BOOTINFO *binfo = (struct BOOTINFO *) 0x0ff0;
+	char s[40], mcursor[256];
+	int mx, my;
 
 	init_palette();
 	init_screen(binfo->vram, binfo->scrnx, binfo->scrny);
-	
+
+	/* 显示鼠标 */
+	mx = (binfo->scrnx - 16) / 2; /* 计算画面的中心坐标*/
+	my = (binfo->scrny - 28 - 16) / 2;
+	init_mouse_cursor8(mcursor, COL8_008484);
+	putblock8_8(binfo->vram, binfo->scrnx, 16, 16, mx, my, mcursor, 16);
+
 	putfonts8_asc(binfo->vram, binfo->scrnx,  8,  8, COL8_FFFFFF, "ABC 123");
 	putfonts8_asc(binfo->vram, binfo->scrnx, 31, 31, COL8_000000, "Haribote OS.");
 	putfonts8_asc(binfo->vram, binfo->scrnx, 30, 30, COL8_FFFFFF, "Haribote OS.");
 
+	sprintf(s, "scrnx = %d", binfo->scrnx);
+	putfonts8_asc(binfo->vram, binfo->scrnx, 16, 64, COL8_FFFFFF, s);
+
 	for (;;) {
 		io_hlt();
 	}
@@ -152,4 +184,103 @@ void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s
 		x += 8;
 	}
 	return;
-}
+}
+
+void init_mouse_cursor8(char *mouse, char bc)
+/* マウスカーソルを準備（16x16） */
+{
+	static char cursor[16][16] = {
+		"**************..",
+		"*OOOOOOOOOOO*...",
+		"*OOOOOOOOOO*....",
+		"*OOOOOOOOO*.....",
+		"*OOOOOOOO*......",
+		"*OOOOOOO*.......",
+		"*OOOOOOO*.......",
+		"*OOOOOOOO*......",
+		"*OOOO**OOO*.....",
+		"*OOO*..*OOO*....",
+		"*OO*....*OOO*...",
+		"*O*......*OOO*..",
+		"**........*OOO*.",
+		"*..........*OOO*",
+		"............*OO*",
+		".............***"
+	};
+	int x, y;
+
+	for (y = 0; y < 16; y++) {
+		for (x = 0; x < 16; x++) {
+			if (cursor[y][x] == '*') {
+				mouse[y * 16 + x] = COL8_000000;
+			}
+			if (cursor[y][x] == 'O') {
+				mouse[y * 16 + x] = COL8_FFFFFF;
+			}
+			if (cursor[y][x] == '.') {
+				mouse[y * 16 + x] = bc;
+			}
+		}
+	}
+	return;
+}
+
+void putblock8_8(char *vram, int vxsize, int pxsize,
+	int pysize, int px0, int py0, char *buf, int bxsize)
+{
+	int x, y;
+	for (y = 0; y < pysize; y++) {
+		for (x = 0; x < pxsize; x++) {
+			vram[(py0 + y) * vxsize + (px0 + x)] = buf[y * bxsize + x];
+		}
+	}
+	return;
+}
+
+void init_gdtidt(void)
+{
+	struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) 0x00270000;
+	struct GATE_DESCRIPTOR    *idt = (struct GATE_DESCRIPTOR    *) 0x0026f800;
+	int i;
+
+	/* GDT初始化 */
+	for (i = 0; i < 8192; i++) {
+		set_segmdesc(gdt + i, 0, 0, 0);
+	}
+	set_segmdesc(gdt + 1, 0xffffffff, 0x00000000, 0x4092);
+	set_segmdesc(gdt + 2, 0x0007ffff, 0x00280000, 0x409a);
+	load_gdtr(0xffff, 0x00270000);
+
+	/* IDT初始化 */
+	for (i = 0; i < 256; i++) {
+		set_gatedesc(idt + i, 0, 0, 0);
+	}
+	load_idtr(0x7ff, 0x0026f800);
+
+	return;
+}
+
+void set_segmdesc(struct SEGMENT_DESCRIPTOR *sd, unsigned int limit, int base, int ar)
+{
+	if (limit > 0xfffff) {
+		ar |= 0x8000; /* G_bit = 1 */
+		limit /= 0x1000;
+	}
+	sd->limit_low    = limit & 0xffff;
+	sd->base_low     = base & 0xffff;
+	sd->base_mid     = (base >> 16) & 0xff;
+	sd->access_right = ar & 0xff;
+	sd->limit_high   = ((limit >> 16) & 0x0f) | ((ar >> 8) & 0xf0);
+	sd->base_high    = (base >> 24) & 0xff;
+	return;
+}
+
+void set_gatedesc(struct GATE_DESCRIPTOR *gd, int offset, int selector, int ar)
+{
+	gd->offset_low   = offset & 0xffff;
+	gd->selector     = selector;
+	gd->dw_count     = (ar >> 8) & 0xff;
+	gd->access_right = ar & 0xff;
+	gd->offset_high  = (offset >> 16) & 0xffff;
+	return;
+}

05_day/naskfunc.nas

@@ -10,6 +10,7 @@
 		GLOBAL	_io_in8,  _io_in16,  _io_in32
 		GLOBAL	_io_out8, _io_out16, _io_out32
 		GLOBAL	_io_load_eflags, _io_store_eflags
+		GLOBAL	_load_gdtr, _load_idtr
 
 [SECTION .text]
 
@@ -75,3 +76,15 @@ _io_store_eflags:	; void io_store_eflags(int eflags);
 		PUSH	EAX
 		POPFD		; POP EFLAGS 
 		RET
+		
+_load_gdtr:		; void load_gdtr(int limit, int addr);
+		MOV		AX,[ESP+4]		; limit
+		MOV		[ESP+6],AX
+		LGDT	[ESP+6]
+		RET
+
+_load_idtr:		; void load_idtr(int limit, int addr);
+		MOV		AX,[ESP+4]		; limit
+		MOV		[ESP+6],AX
+		LIDT	[ESP+6]
+		RET