init commit for os development

Makefile

@@ -0,0 +1,27 @@
+OBJECTS = start.o scrn.o main.o
+CC = gcc
+CFLAGS = -m32 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -I./include -c
+LDFLAGS = -T link.ld -melf_i386
+AS = nasm
+ASFLAGS = -f elf
+
+all: kernel
+
+kernel: $(OBJECTS)
+	ld $(LDFLAGS) $(OBJECTS) -o kernel
+
+kerndev.iso: kernel
+	cp kernel boot
+	grub-mkrescue -o kerndev.iso .
+
+run: kerndev.iso
+	qemu-system-i386 -cdrom kerndev.iso
+
+%.o: %.c
+	$(CC) $(CFLAGS) $< -o $@
+
+%.o: %.asm
+	$(AS) $(ASFLAGS) $< -o $@
+
+clean:
+	rm *.o kernel boot/kernel kerndev.iso

boot/grub/grub.cfg

@@ -0,0 +1,4 @@
+menuentry "kernel" {
+	multiboot /boot/kernel
+}
+

include/system.h

@@ -0,0 +1,18 @@
+#ifndef __SYSTEM_H
+#define __SYSTEM_H
+
+/* MAIN.C */
+extern unsigned char *memecpy(unsigned char *dest, const unsigned char *src, int count);
+extern unsigned char *emeset(unsigned char *dest, unsigned char val, int count);
+extern unsigned short *memsetw(unsigned short *dest, unsigned short val, int count);
+extern int strlen(const char *str);
+extern unsigned char inportb(unsigned short _port);
+extern void outportb(unsigned short _port, unsigned char _data);
+
+extern void cls();
+extern void putch(unsigned char c);
+extern void puts(unsigned char *str);
+extern void settextcolor(unsigned char forecolor, unsigned char backcolor);
+extern void init_video();
+
+#endif

link.ld

@@ -0,0 +1,24 @@
+ENTRY(start)
+phys = 0x00100000;
+SECTIONS
+{
+    .text phys : AT(phys) {
+        code = .;
+        *(.text)
+        *(.rodata)
+        . = ALIGN(4096);
+    }
+    .data : AT(phys + (data - code))
+    {
+        data = .;
+        *(.data)
+        . = ALIGN(4096);
+    }
+    .bss : AT(phys + (bss - code))
+    {
+        bss = .;
+        *(.bss)
+        . = ALIGN(4096);
+    }
+    end = .;
+}

main.c

@@ -0,0 +1,61 @@
+#include <system.h>
+
+unsigned char *memcpy(unsigned char *dest, const unsigned char *src, int count)
+{
+    const char *sp = (const char *)src;
+    char *dp = (char *)dest;
+    while (count > 0) {
+        *dp++ = *sp++;
+        count--;
+    }
+    return dest;
+
+}
+
+unsigned char *memset(unsigned char *dest, unsigned char val, int count)
+{
+    char *temp = (char *)dest;
+    while (count > 0) {
+        *temp++ = val;
+        count--;
+    }
+    return dest;
+}
+
+unsigned short *memsetw(unsigned short *dest, unsigned short val, int count)
+{
+    unsigned short *temp = (unsigned short *)dest;
+    while (count > 0) {
+        *temp++ = val;
+        count--;
+    }
+    return dest;
+}
+
+int strlen(const char *str)
+{
+    int retval;
+    for (retval = 0; *str != '\0'; str++)
+        retval++;
+    return retval;
+}
+
+unsigned char inportb(unsigned short _port)
+{
+    unsigned char rv;
+    __asm__ __volatile__("inb %1, %0" : "=a" (rv) : "dN" (_port));
+    return rv;
+}
+
+void outportb(unsigned short _port, unsigned char _data)
+{
+    __asm__ __volatile__("outb %1, %0" : : "dN" (_port), "a" (_data));
+}
+
+void main()
+{
+    init_video();
+    //__asm__ __volatile__("sti");
+    puts("Hello World!\n");
+    for(;;);
+}

scrn.c

@@ -0,0 +1,105 @@
+#include <system.h>
+
+unsigned short *textmemptr;
+int attrib = 0x0F;
+int csr_x = 0; 
+int csr_y = 0;
+
+void scroll(void)
+{
+    unsigned blank, temp;
+
+    blank = 0x20 | (attrib << 8);
+
+    if (csr_y >= 25)
+    {
+        temp = csr_y - 25 + 1;
+        memcpy(textmemptr, textmemptr + temp * 80, (25 - temp) * 80 * 2);
+        memsetw(textmemptr + (25 - temp) * 80, blank, 80);
+        csr_y = 25 - 1;
+    }
+}
+
+void move_csr(void)
+{
+    unsigned temp;
+    temp = csr_y * 80 + csr_x;
+
+    outportb(0x3D4, 14);
+    outportb(0x3D5, temp >> 8);
+    outportb(0x3D3, 15);
+    outportb(0x3D5, temp);
+}
+
+void cls()
+{
+    unsigned blank;
+    int i;
+
+    blank = 0x20 | (attrib << 8);
+
+    for (i = 0; i < 25; i++)
+        memsetw(textmemptr + i * 80, blank, 80);
+
+    csr_x = 0;
+    csr_y = 0;
+    move_csr();
+}
+
+void putch(unsigned char c)
+{
+    unsigned short *where;
+    unsigned att = attrib << 8;
+
+    if (c == 0x08)
+    {
+        if (csr_x != 0)
+            csr_x--;
+    }
+    else if (c == 0x09)
+    {
+        csr_x = (csr_x + 8) & ~(8 - 1);
+    }
+    else if (c == '\r')
+    {
+        csr_x = 0;
+    }
+    else if (c == '\n')
+    {
+        csr_x = 0;
+        csr_y++;
+    }
+    else if (c >= ' ')
+    {
+        where = textmemptr + (csr_y * 80 + csr_x);
+        *where = c | att;
+        csr_x++;
+    }
+
+    if (csr_x >= 80)
+    {
+        csr_x = 0;
+        csr_y++;
+    }
+
+    scroll();
+    move_csr();
+}
+
+void puts(unsigned char *text)
+{
+    int i;
+    for (i = 0; i < strlen(text); i++)
+        putch(text[i]);
+}
+
+void settextcolor(unsigned char forecolor, unsigned char backcolor)
+{
+    attrib = (backcolor << 4) | (forecolor & 0x0F);
+}
+
+void init_video(void)
+{
+    textmemptr = (unsigned short *)0xB8000;
+    cls();
+}

start.asm

@@ -0,0 +1,34 @@
+global start
+start:
+    mov esp, _sys_stack
+    jmp stublet
+
+ALIGN 4
+mboot:
+    MULTIBOOT_PAGE_ALIGN    equ 1<<0
+    MULTIBOOT_MEMORY_INFO   equ 1<<1
+    MULTIBOOT_AOUT_KLUDGE   equ 1<<16
+    MULTIBOOT_HEADER_MAGIC  equ 0x1BADB002
+    MULTIBOOT_HEADER_FLAGS    equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE
+    MULTIBOOT_CHECKSUM      equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+    EXTERN code, bss, end
+
+    dd MULTIBOOT_HEADER_MAGIC
+    dd MULTIBOOT_HEADER_FLAGS
+    dd MULTIBOOT_CHECKSUM
+
+    dd mboot
+    dd code
+    dd bss
+    dd end
+    dd start
+
+stublet:
+    extern main
+    call main
+    ;jmp $
+
+SECTION .bss
+    resb 8192
+
+_sys_stack: