OS作成奮闘記day6

割り込み命令を作るために、GDT/IDTから作成していきます。
bootpack.c

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 init_gdtidt(void) {
    struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) 0x00270000;
    struct GATE_DESCRIPTOR *idt = (struct GATE_DESCRIPTOR *) 0x0026f800;
    int i;

    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);

    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 > 0xffff) {
        ar |= 0x8000;
        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;
}

nasfunc.nas

GLOBAL  _load_gdtr, _load_idtr

_load_gdtr:
        MOV     AX,[ESP+4]
        MOV     [ESP+6],AX
        LGDT    [ESP+6]
        RET

_load_idtr:
        MOV     AX,[ESP+4]
        MOV     [ESP+6],AX
        LIDT    [ESP+6]
        RET

make runをしても前回と何も変わらないですが、これが6日目の布石になるみたいです。

ここからは6日目の内容になります。
まずはbootpack.cが長すぎるのでファイルを分割しました。
ついでにMakefileも改造しています。

bootpack.c

TOOLPATH = ..\..\z_tools\\

INCPATH  = ..\..\z_tools\haribote\\

MAKE     = $(TOOLPATH)make.exe -r
NASK     = $(TOOLPATH)nask.exe
CC1      = $(TOOLPATH)cc1.exe -I$(INCPATH) -Os -Wall -quiet
GAS2NASK = $(TOOLPATH)gas2nask.exe -a
OBJ2BIM  = $(TOOLPATH)obj2bim.exe
MAKEFONT = $(TOOLPATH)makefont.exe
BIN2OBJ  = $(TOOLPATH)bin2obj
BIM2HRB  = $(TOOLPATH)bim2hrb.exe
RULEFILE = $(TOOLPATH)haribote\haribote.rul
EDIMG    = $(TOOLPATH)edimg.exe
IMGTOL   = $(TOOLPATH)imgtol.com
COPY     = cmd.exe /C copy
DEL      = rm -f


# default operation
default:
    $(MAKE) img

# file making rule

ipl10.bin : ipl10.nas Makefile
    $(NASK) ipl10.nas ipl10.bin ipl10.lst

asmhead.bin : asmhead.nas Makefile
    $(NASK) asmhead.nas asmhead.bin asmhead.lst

bootpack.gas : bootpack.c Makefile
    $(CC1) -o bootpack.gas bootpack.c

bootpack.nas : bootpack.gas Makefile
    $(GAS2NASK) bootpack.gas  bootpack.nas 

bootpack.obj : bootpack.nas Makefile
    $(NASK) bootpack.nas bootpack.obj bootpack.lst

naskfunc.obj : naskfunc.nas Makefile
    $(NASK) naskfunc.nas naskfunc.obj naskfunc.lst

hankaku.bin : hankaku.txt Makefile
    $(MAKEFONT) hankaku.txt hankaku.bin

hankaku.obj : hankaku.bin Makefile
    $(BIN2OBJ) hankaku.bin hankaku.obj _hankaku

graphic.gas : graphic.c Makefile
    $(CC1) -o graphic.gas graphic.c

graphic.nas : graphic.gas Makefile
    $(GAS2NASK) graphic.gas graphic.nas

graphic.obj : graphic.nas Makefile
    $(NASK) graphic.nas graphic.obj graphic.lst

dsctbl.gas : dsctbl.c Makefile
    $(CC1) -o dsctbl.gas dsctbl.c

dsctbl.nas : dsctbl.gas Makefile
    $(GAS2NASK) dsctbl.gas dsctbl.nas

dsctbl.obj : dsctbl.nas Makefile
    $(NASK) dsctbl.nas dsctbl.obj dsctbl.lst

bootpack.bim : bootpack.obj naskfunc.obj hankaku.obj graphic.obj dsctbl.obj Makefile
    $(OBJ2BIM) @$(RULEFILE) out:bootpack.bim stack:3136k map:bootpack.map \
        bootpack.obj naskfunc.obj hankaku.obj graphic.obj dsctbl.obj
# 3MB+64KB=3136KB

bootpack.hrb : bootpack.bim Makefile
    $(BIM2HRB) bootpack.bim bootpack.hrb 0

haribote.sys : asmhead.bin bootpack.hrb Makefile
    cat asmhead.bin >  haribote.sys
    cat bootpack.hrb >> haribote.sys

haribote.img : ipl10.bin haribote.sys Makefile
    $(EDIMG)   imgin:..\..\z_tools\fdimg0at.tek \
        wbinimg src:ipl10.bin len:512 from:0 to:0 \
        copy from:haribote.sys to:@: \
        imgout:haribote.img

# command

img :
    $(MAKE) haribote.img

run :
    $(MAKE) img
    $(COPY) haribote.img ..\..\z_tools\qemu\fdimage0.bin
    $(MAKE) -C ..\..\z_tools\qemu

install :
    $(MAKE) img
    $(IMGTOL) w a: haribote.img

clean :
    -$(DEL) *.bin
    -$(DEL) *.lst
    -$(DEL) *.gas
    -$(DEL) *.obj
    -$(DEL) bootpack.nas
    -$(DEL) bootpack.map
    -$(DEL) bootpack.bim
    -$(DEL) bootpack.hrb
    -$(DEL) haribote.sys

src_only :
    $(MAKE) clean
    -$(DEL) haribote.img

graphic.c

/* graphic process */

void io_hlt(void);
void io_cli(void);
void io_out8(int port, int data);
int io_load_eflags(void);
void io_store_eflags(int eflags);

void init_palette(void);
void set_palette(int start, int end, unsigned char *rgd);
void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1);
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
#define COL8_00FF00  2
#define COL8_FFFF00  3
#define COL8_0000FF  4
#define COL8_FF00FF  5
#define COL8_00FFFF  6
#define COL8_FFFFFF  7
#define COL8_C6C6C6  8
#define COL8_840000  9
#define COL8_008400  10
#define COL8_848400  11
#define COL8_000084  12
#define COL8_840084  13
#define COL8_008484  14
#define COL8_848484  15

void init_palette(void)
{
    static unsigned char table_rgb[16 * 3] = {
        0x00, 0x00, 0x00,   /* 0:black */
        0xff, 0x00, 0x00,   /* 1:light red */
        0x00, 0xff, 0x00,   /* 2:light green */
        0xff, 0xff, 0x00,   /* 3:light yellow */
        0x00, 0x00, 0xff,   /* 4:light blue */
        0xff, 0x00, 0xff,   /* 5:light puple */
        0x00, 0xff, 0xff,   /* 6:light sky blue */
        0xff, 0xff, 0xff,   /* 7:white */
        0xc6, 0xc6, 0xc6,   /* 8:light grey */
        0x84, 0x00, 0x00,   /* 9:dark green */
        0x00, 0x84, 0x00,   /* 10:dark green */
        0x84, 0x84, 0x00,   /* 11:dark yellow */
        0x00, 0x00, 0x84,   /* 12:dark blue */
        0x84, 0x00, 0x84,   /* 13:dark puple */
        0x00, 0x84, 0x84,   /* 14:dark sky blue */
        0x84, 0x84, 0x84    /* 15:dark grey */
    };
    set_palette(0, 15, table_rgb);
    return;
}

void set_palette(int start, int end, unsigned char *rgb)
{
    int i, eflags;
    eflags = io_load_eflags();
    io_cli();
    io_out8(0x03c8, start);
    for (i = start; i <= end; i++) {
        io_out8(0x03c9, rgb[0] / 4);
        io_out8(0x03c9, rgb[1] / 4);
        io_out8(0x03c9, rgb[2] / 4);
        rgb += 3;
    }
    io_store_eflags(eflags);
    return;
} 

void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1)
{
    int x, y;
    for (y= y0; y <= y1; y++) {
        for (x = x0; x <= x1; x++)
            vram[y * xsize + x] = c;
    }
    return;
}

void init_screen(char *vram, int x, int y)
{
    boxfill8(vram, x, COL8_008484,  0,          0,       x - 1,    y - 29);
    boxfill8(vram, x, COL8_C6C6C6,  0,          y - 28,  x - 1,    y - 28);
    boxfill8(vram, x, COL8_FFFFFF,  0,          y - 27,  x - 1,    y - 27);
    boxfill8(vram, x, COL8_C6C6C6,  0,          y - 26,  x - 1,    y -  1);

    boxfill8(vram, x, COL8_FFFFFF,  3,          y - 24,  59,       y - 24);
    boxfill8(vram, x, COL8_FFFFFF,  2,          y - 24,   2,       y -  4);
    boxfill8(vram, x, COL8_848484,  3,          y -  4,  59,       y -  4);
    boxfill8(vram, x, COL8_848484, 59,          y - 23,  59,       y -  5);
    boxfill8(vram, x, COL8_000000,  2,          y -  3,  59,       y -  3);
    boxfill8(vram, x, COL8_000000, 60,          y - 24,  60,       y -  3);

    boxfill8(vram, x, COL8_848484, x - 47,      y - 24,  x -  4,   y - 24);
    boxfill8(vram, x, COL8_848484, x - 47,      y - 23,  x - 47,   y -  4);
    boxfill8(vram, x, COL8_FFFFFF, x - 47,      y -  3,  x -  4,   y -  3);
    boxfill8(vram, x, COL8_FFFFFF, x -  3,      y - 24,  x -  3,   y -  3);
    return;
}

void putfont8(char *vram, int xsize, int x, int y, char c, char *font)
{
    int i;
    char *p, d;
    for (i = 0; i < 16; i++) {
        p = vram + (y + i) * xsize + x;
        d = font[i];
        if ((d & 0x80) != 0) { p[0] = c; }
        if ((d & 0x40) != 0) { p[1] = c; }
        if ((d & 0x20) != 0) { p[2] = c; }
        if ((d & 0x10) != 0) { p[3] = c; }
        if ((d & 0x08) != 0) { p[4] = c; }
        if ((d & 0x04) != 0) { p[5] = c; }
        if ((d & 0x02) != 0) { p[6] = c; }
        if ((d & 0x01) != 0) { p[7] = c; }
    }
    return ;
}

void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s)
{
    extern char hankaku[4096];
    for (; *s != 0x00; s++) {
        putfont8(vram, xsize, x, y, c, hankaku + *s * 16);
        x += 8;
    }
    return;
}

void init_mouse_cursor8(char *mouse, char bc)
{
    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; 
}

dsctbl.c

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 init_gdtidt(void) {
    struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) 0x00270000;
    struct GATE_DESCRIPTOR *idt = (struct GATE_DESCRIPTOR *) 0x0026f800;
    int i;

    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);

    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 > 0xffff) {
        ar |= 0x8000;
        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;
}

Makefile

TOOLPATH = ..\..\z_tools\\

INCPATH  = ..\..\z_tools\haribote\\

MAKE     = $(TOOLPATH)make.exe -r
NASK     = $(TOOLPATH)nask.exe
CC1      = $(TOOLPATH)cc1.exe -I$(INCPATH) -Os -Wall -quiet
GAS2NASK = $(TOOLPATH)gas2nask.exe -a
OBJ2BIM  = $(TOOLPATH)obj2bim.exe
MAKEFONT = $(TOOLPATH)makefont.exe
BIN2OBJ  = $(TOOLPATH)bin2obj
BIM2HRB  = $(TOOLPATH)bim2hrb.exe
RULEFILE = $(TOOLPATH)haribote\haribote.rul
EDIMG    = $(TOOLPATH)edimg.exe
IMGTOL   = $(TOOLPATH)imgtol.com
COPY     = cmd.exe /C copy
DEL      = rm -f


# default operation
default:
    $(MAKE) img

# file making rule

ipl10.bin : ipl10.nas Makefile
    $(NASK) ipl10.nas ipl10.bin ipl10.lst

asmhead.bin : asmhead.nas Makefile
    $(NASK) asmhead.nas asmhead.bin asmhead.lst

bootpack.gas : bootpack.c Makefile
    $(CC1) -o bootpack.gas bootpack.c

bootpack.nas : bootpack.gas Makefile
    $(GAS2NASK) bootpack.gas  bootpack.nas 

bootpack.obj : bootpack.nas Makefile
    $(NASK) bootpack.nas bootpack.obj bootpack.lst

naskfunc.obj : naskfunc.nas Makefile
    $(NASK) naskfunc.nas naskfunc.obj naskfunc.lst

hankaku.bin : hankaku.txt Makefile
    $(MAKEFONT) hankaku.txt hankaku.bin

hankaku.obj : hankaku.bin Makefile
    $(BIN2OBJ) hankaku.bin hankaku.obj _hankaku

graphic.gas : graphic.c Makefile
    $(CC1) -o graphic.gas graphic.c

graphic.nas : graphic.gas Makefile
    $(GAS2NASK) graphic.gas graphic.nas

graphic.obj : graphic.nas Makefile
    $(NASK) graphic.nas graphic.obj graphic.lst

dsctbl.gas : dsctbl.c Makefile
    $(CC1) -o dsctbl.gas dsctbl.c

dsctbl.nas : dsctbl.gas Makefile
    $(GAS2NASK) dsctbl.gas dsctbl.nas

dsctbl.obj : dsctbl.nas Makefile
    $(NASK) dsctbl.nas dsctbl.obj dsctbl.lst

bootpack.bim : bootpack.obj naskfunc.obj hankaku.obj graphic.obj dsctbl.obj Makefile
    $(OBJ2BIM) @$(RULEFILE) out:bootpack.bim stack:3136k map:bootpack.map \
        bootpack.obj naskfunc.obj hankaku.obj graphic.obj dsctbl.obj
# 3MB+64KB=3136KB

bootpack.hrb : bootpack.bim Makefile
    $(BIM2HRB) bootpack.bim bootpack.hrb 0

haribote.sys : asmhead.bin bootpack.hrb Makefile
    cat asmhead.bin >  haribote.sys
    cat bootpack.hrb >> haribote.sys

haribote.img : ipl10.bin haribote.sys Makefile
    $(EDIMG)   imgin:..\..\z_tools\fdimg0at.tek \
        wbinimg src:ipl10.bin len:512 from:0 to:0 \
        copy from:haribote.sys to:@: \
        imgout:haribote.img

# command

img :
    $(MAKE) haribote.img

run :
    $(MAKE) img
    $(COPY) haribote.img ..\..\z_tools\qemu\fdimage0.bin
    $(MAKE) -C ..\..\z_tools\qemu

install :
    $(MAKE) img
    $(IMGTOL) w a: haribote.img

clean :
    -$(DEL) *.bin
    -$(DEL) *.lst
    -$(DEL) *.gas
    -$(DEL) *.obj
    -$(DEL) bootpack.nas
    -$(DEL) bootpack.map
    -$(DEL) bootpack.bim
    -$(DEL) bootpack.hrb
    -$(DEL) haribote.sys

src_only :
    $(MAKE) clean
    -$(DEL) haribote.img

Makefileが長くなりすぎたので短くします。

Makefile

OBJS_BOOTPACK = bootpack.obj naskfunc.obj hankaku.obj graphic.obj dsctbl.obj

TOOLPATH = ..\..\z_tools\\

INCPATH  = ..\..\z_tools\haribote\\

MAKE     = $(TOOLPATH)make.exe -r
NASK     = $(TOOLPATH)nask.exe
CC1      = $(TOOLPATH)cc1.exe -I$(INCPATH) -Os -Wall -quiet
GAS2NASK = $(TOOLPATH)gas2nask.exe -a
OBJ2BIM  = $(TOOLPATH)obj2bim.exe
MAKEFONT = $(TOOLPATH)makefont.exe
BIN2OBJ  = $(TOOLPATH)bin2obj
BIM2HRB  = $(TOOLPATH)bim2hrb.exe
RULEFILE = $(TOOLPATH)haribote\haribote.rul
EDIMG    = $(TOOLPATH)edimg.exe
IMGTOL   = $(TOOLPATH)imgtol.com
COPY     = cmd.exe /C copy
DEL      = rm -f


# default operation
default:
    $(MAKE) img

# file making rule

ipl10.bin : ipl10.nas Makefile
    $(NASK) ipl10.nas ipl10.bin ipl10.lst

asmhead.bin : asmhead.nas Makefile
    $(NASK) asmhead.nas asmhead.bin asmhead.lst

hankaku.bin : hankaku.txt Makefile
    $(MAKEFONT) hankaku.txt hankaku.bin

hankaku.obj : hankaku.bin Makefile
    $(BIN2OBJ) hankaku.bin hankaku.obj _hankaku

bootpack.bim : $(OBJS_BOOTPACK) Makefile
    $(OBJ2BIM) @$(RULEFILE) out:bootpack.bim stack:3136k map:bootpack.map \
        $(OBJS_BOOTPACK)
# 3MB+64KB=3136KB

bootpack.hrb : bootpack.bim Makefile
    $(BIM2HRB) bootpack.bim bootpack.hrb 0

haribote.sys : asmhead.bin bootpack.hrb Makefile
    cat asmhead.bin >  haribote.sys
    cat bootpack.hrb >> haribote.sys

haribote.img : ipl10.bin haribote.sys Makefile
    $(EDIMG)   imgin:..\..\z_tools\fdimg0at.tek \
        wbinimg src:ipl10.bin len:512 from:0 to:0 \
        copy from:haribote.sys to:@: \
        imgout:haribote.img

# rules
%.gas : %.c Makefile
    $(CC1) -o $*.gas $*.c

%.nas : %.gas Makefile
    $(GAS2NASK) $*.gas $*.nas

%.obj :%.nas Makefile
    $(NASK) $*.nas $*.obj $*.lst

# command

img :
    $(MAKE) haribote.img

run :
    $(MAKE) img
    $(COPY) haribote.img ..\..\z_tools\qemu\fdimage0.bin
    $(MAKE) -C ..\..\z_tools\qemu

install :
    $(MAKE) img
    $(IMGTOL) w a: haribote.img

clean :
    -$(DEL) *.bin
    -$(DEL) *.lst
    -$(DEL) *.gas
    -$(DEL) *.obj
    -$(DEL) bootpack.nas
    -$(DEL) bootpack.map
    -$(DEL) bootpack.bim
    -$(DEL) bootpack.hrb
    -$(DEL) haribote.sys

src_only :
    $(MAKE) clean
    -$(DEL) haribote.img

これでだいぶ短くなりました。

さらにヘッダーファイルを記載していきます。
bootpack.h

/* asmhead.nad */
struct BOOTINFO {
    char cyls, leds, vmode, reserve;
    short scrnx, scrny;
    char *vram;
};
#define ADR_BOOTINFO

/* naskfunc.nas */
void io_hlt(void);
void io_cli(void);
void io_out8(int port, int data);
int io_load_eflags(void);
void io_store_eflags(int eflags);
void load_gdtr(int limit, int addr);
void load_idtr(int limit, int addr);

/* graphic.c */
void init_palette(void);
void set_palette(int start, int end, unsigned char *rgd);
void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1);
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
#define COL8_00FF00  2
#define COL8_FFFF00  3
#define COL8_0000FF  4
#define COL8_FF00FF  5
#define COL8_00FFFF  6
#define COL8_FFFFFF  7
#define COL8_C6C6C6  8
#define COL8_840000  9
#define COL8_008400  10
#define COL8_848400  11
#define COL8_000084  12
#define COL8_840084  13
#define COL8_008484  14
#define COL8_848484  15

/* dsctbl.c */
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);
#define ADR_IDT         0x0026f800
#define LIMIT_IDT       0x000007ff
#define ADR_GDT         0x00270000
#define LIMIT_GDT       0x0000ffff
#define ADR_BOTPAK      0x00280000
#define LIMIT_BOTPAK    0x0007ffff
#define AR_DATA32_RW    0x4092
#define AR_CODE32_ER    0x409a

ヘッダーファイルを作ったことでCのソースファイルも短縮することができるようになりました。
bootpack.c

#include "bootpack.h"
#include <stdio.h>

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);
    mx = (binfo->scrnx - 16) / 2;
    my = (binfo->scrny - 28 - 16) / 2;
    init_mouse_cursor8(mcursor, COL8_008484);
    putblock8_8(binfo->vram, binfo->scrnx, 16, 16, mx, my, mcursor, 16);
    sprintf(s, "(%d, %d)", mx, my);
    putfonts8_asc(binfo->vram, binfo->scrnx, 0, 0, COL8_FFFFFF, s);

    for (;;) {
        io_hlt();
    }
    
}

graphic.c

/* graphic process */
#include "bootpack.h"

void init_palette(void)
{
    static unsigned char table_rgb[16 * 3] = {
        0x00, 0x00, 0x00,   /* 0:black */
        0xff, 0x00, 0x00,   /* 1:light red */
        0x00, 0xff, 0x00,   /* 2:light green */
        0xff, 0xff, 0x00,   /* 3:light yellow */
        0x00, 0x00, 0xff,   /* 4:light blue */
        0xff, 0x00, 0xff,   /* 5:light puple */
        0x00, 0xff, 0xff,   /* 6:light sky blue */
        0xff, 0xff, 0xff,   /* 7:white */
        0xc6, 0xc6, 0xc6,   /* 8:light grey */
        0x84, 0x00, 0x00,   /* 9:dark green */
        0x00, 0x84, 0x00,   /* 10:dark green */
        0x84, 0x84, 0x00,   /* 11:dark yellow */
        0x00, 0x00, 0x84,   /* 12:dark blue */
        0x84, 0x00, 0x84,   /* 13:dark puple */
        0x00, 0x84, 0x84,   /* 14:dark sky blue */
        0x84, 0x84, 0x84    /* 15:dark grey */
    };
    set_palette(0, 15, table_rgb);
    return;
}

void set_palette(int start, int end, unsigned char *rgb)
{
    int i, eflags;
    eflags = io_load_eflags();
    io_cli();
    io_out8(0x03c8, start);
    for (i = start; i <= end; i++) {
        io_out8(0x03c9, rgb[0] / 4);
        io_out8(0x03c9, rgb[1] / 4);
        io_out8(0x03c9, rgb[2] / 4);
        rgb += 3;
    }
    io_store_eflags(eflags);
    return;
} 

void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1)
{
    int x, y;
    for (y= y0; y <= y1; y++) {
        for (x = x0; x <= x1; x++)
            vram[y * xsize + x] = c;
    }
    return;
}

void init_screen(char *vram, int x, int y)
{
    boxfill8(vram, x, COL8_008484,  0,          0,       x - 1,    y - 29);
    boxfill8(vram, x, COL8_C6C6C6,  0,          y - 28,  x - 1,    y - 28);
    boxfill8(vram, x, COL8_FFFFFF,  0,          y - 27,  x - 1,    y - 27);
    boxfill8(vram, x, COL8_C6C6C6,  0,          y - 26,  x - 1,    y -  1);

    boxfill8(vram, x, COL8_FFFFFF,  3,          y - 24,  59,       y - 24);
    boxfill8(vram, x, COL8_FFFFFF,  2,          y - 24,   2,       y -  4);
    boxfill8(vram, x, COL8_848484,  3,          y -  4,  59,       y -  4);
    boxfill8(vram, x, COL8_848484, 59,          y - 23,  59,       y -  5);
    boxfill8(vram, x, COL8_000000,  2,          y -  3,  59,       y -  3);
    boxfill8(vram, x, COL8_000000, 60,          y - 24,  60,       y -  3);

    boxfill8(vram, x, COL8_848484, x - 47,      y - 24,  x -  4,   y - 24);
    boxfill8(vram, x, COL8_848484, x - 47,      y - 23,  x - 47,   y -  4);
    boxfill8(vram, x, COL8_FFFFFF, x - 47,      y -  3,  x -  4,   y -  3);
    boxfill8(vram, x, COL8_FFFFFF, x -  3,      y - 24,  x -  3,   y -  3);
    return;
}

void putfont8(char *vram, int xsize, int x, int y, char c, char *font)
{
    int i;
    char *p, d;
    for (i = 0; i < 16; i++) {
        p = vram + (y + i) * xsize + x;
        d = font[i];
        if ((d & 0x80) != 0) { p[0] = c; }
        if ((d & 0x40) != 0) { p[1] = c; }
        if ((d & 0x20) != 0) { p[2] = c; }
        if ((d & 0x10) != 0) { p[3] = c; }
        if ((d & 0x08) != 0) { p[4] = c; }
        if ((d & 0x04) != 0) { p[5] = c; }
        if ((d & 0x02) != 0) { p[6] = c; }
        if ((d & 0x01) != 0) { p[7] = c; }
    }
    return ;
}

void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s)
{
    extern char hankaku[4096];
    for (; *s != 0x00; s++) {
        putfont8(vram, xsize, x, y, c, hankaku + *s * 16);
        x += 8;
    }
    return;
}

void init_mouse_cursor8(char *mouse, char bc)
{
    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; 
}

dsctbl.c

#include "bootpack.h"

void init_gdtidt(void) {
    struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) 0x00270000;
    struct GATE_DESCRIPTOR *idt = (struct GATE_DESCRIPTOR *) 0x0026f800;
    int i;

    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);

    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 > 0xffff) {
        ar |= 0x8000;
        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;
}

ヘッダーファイルを分割したことでさらに見やすくなりました。

実装過程
・　6bf8c9f4729c76f7ab788aef9405847f1c7eb1cd