ld: cannot perform PE operations on non PE output file error

Question

I am new to operating system programming and I am reading a book which gives a simple example of kernel as follows:

main() {
   char *video_memory = 0xb8000;
           


        

Answer 1

The first thing you'll need to is change the name of you function. If you call it main the MinGW version of GCC will insert a call to __main to do initialization. For example:

start() {
   char *video_memory = 0xb8000;
   *video_memory = 'X';
}

This means you'll also have to edit kernel_entry.asm accordingly:

[bits 32]
[extern _start]
call _start
jmp $ 

Next compile and assemble the two files as you did before, and link it with these commands:

ld -T NUL -o kernel.tmp -Ttext 0x1000 kernel_entry.o kernel.o
objcopy -O binary -j .text  kernel.tmp kernel.bin 

The first command links the objects as a PECOFF executable, and then the second command converts it to a binary. Now combine the binary with the boot loader:

copy /b boot_sect.bin+kernel.bin os-image