一个内核的helloworld

编程技术  /  houtizong 发布于 3年前   147

项目代码 https://github.com/killinux/mkernel

下载qemu，模拟器http://qemu.weilnetz.de/w32/qemu-20130616-w32.exe
安装后使用
E:\Program Files (x86)\qemu>qemu-system-i386.exe
代码如下
kernel.asm

bits 32section .text        ;multiboot spec        align 4        dd 0x1BADB002              ;magic        dd 0x00                    ;flags        dd - (0x1BADB002 + 0x00)   ;checksum. m+f+c should be zeroglobal startextern kmain            ;this is defined in the c filestart:  cli                           ;block interrupts  call kmain  hlt                           ;halt the CPU

kernel.c

void kmain(void){        char *str = "my first kernel";        //video memory begins at address 0xb8000        char *vidptr = (char*)0xb8000;        unsigned int i = 0;        unsigned int j = 0;        //this loops clears the screen        //there are 25 lines each of 80 columns; each element takes 2 bytes        while(j < 80 * 25 * 2) {                //blank character                vidptr[j] = ' ';                //attribute-byte                vidptr[j+1] = 0x07;                 j = j + 2;        }        j = 0;        //this loop write the string to video memory        while(str[j] != '\0') {                //the character's ascii                vidptr[i] = str[j];                //attribute-byte: give character black bg and-light grey fg                vidptr[i+1] = 0x07;                ++j;                i = i + 2;        }        return;}

link.ld

OUTPUT_FORMAT(elf32-i386)ENTRY(start)SECTIONS {   . = 0x100000;   .text : { *(.text) }   .data : { *(.data) }   .bss  : { *(.bss)  } }

nasm -f elf32 kernel.asm -o kasm.o
gcc -m32 -c kernel.c -o kc.o
ld -m elf_i386 -T link.ld -o kernel kasm.o kc.o
sz kernel

E:\Program Files (x86)\qemu>qemu-system-i386.exe -kernel kernel

参考
http://www.geekfan.net/8663/