Re: [Qemu-discuss] Experimenting with x86 real mode code in qemu

[Bodo Eggert]

On Tue, 8 Dec 2015, Jay Aurabind wrote:

> Thank you for you response Jakob. Please see my inline replies
> 
> On 7 December 2015 at 21:18, Jakob Bohm <address@hidden> wrote:
> > On 07/12/2015 16:17, Jay Aurabind wrote:

> I am be beginnner at making linker scripts. I intended to put a jmp
> instruction at 0XFFFF0:
> 
> OUTPUT(binary);
> ENTRY(start);
> SECTIONS
> {
>     .text : { *(.text) }
>     .data : { *(.data) }
>     .bss : { *(.bss COMMON) }
>     . = 0xFFFF0;
>     .startup . : { startup.o (.text)}
> }


I don't know about your assembler, but for a classic BIOS, you should have 
exactly 65536 bytes, and in your file at 0xfff0, there should be the jump 
instructions.

The jump should point to the function using a long jump with the full 
destination address of your code.

JMP F000:1234 ; Your code is at 0x1234 in the file
(ea 34 12 00 f0)

https://en.wikipedia.org/wiki/JMP_(x86_instruction)