Hello Sir, I am using DELL laptop and with the help of QEMU, NASM and GCC i am trying to compile a simple code which is not executing properly. I am using UBUNTU 10.04.
here is the loader.asm assembly file.
global loader
extern dmain
MODULEALIGN equ 1<<0
MEMINFO equ 1<<1
FLAGS equ MODULEALIGN | MEMINFO
MAGIC equ 0x1BADB002
CHECKSUM equ -(MAGIC + FLAGS)
section .text
align 4
MultiBootHeader:
dd MAGIC
dd FLAGS
dd CHECKSUM
STACKSIZE equ 0x4000
loader:
mov esp, stack+STACKSIZE
push eax
push ebx
call dmain
cli
hang:
hlt
jmp hang
section .bss
align 4
stack :
resb STACKSIZE$nasm -f elf loader.o loader.asm
my c program kernel.c
void dmain(void* mbd ,unsigned int magic)
{
if(magic !=0x1BADB002)
{
clr();
print("Error:Invalid Number",0xAF);
}
else
{
clr();
print("Hello World",0xAF);
}
}
void print(char* msg,int color)
{
char* mem=(char*) 0xB8000;
while(*msg !=0)
{
*mem= *msg;
mem++;
msg++;
*mem=(char*) color;
mem++;
}
}
void clr(void)
{
char* mem=(char*) 0xB8000;
while(*mem !=0)
{
*mem = 0;
mem++;
}
}$gcc -o kernel.o -c kernel.c -Wall -Wextra -nostdlib -nostartfiles -nodefaultlibs
linker prorgram linker.ld
ENTRY(loader)
SECTIONS{
. =0x00100000 ;
.text :{
*(.text)
}
.rodata ALIGN (0x1000) :{
*(.data)
}
.bss : {
sbss = .;
*(COMMON)
*(.bss)
ebss = .;
}
}$ld -T linker.ld -o kernel.bin loader.o kernel.o
$qemu -kernel -kernel.bin
in the output part of QEMU , nothing is displayed. I tried to find error but i am not getting it, Its also not like that its not addressing video memory as in my output clr() is working and clearing the screen but print() is not working it should give output:- Error:Invalid Number.
I am not getting the error, Please help me out..:(
