Re: [Qemu-devel] Re: Detecting an assembly instruction in QEMU

[Atif Hashmi]

Hi Eduardo,

I really appreciate your help but there is a small think that I need to ask you. 

In target-i386/translate.c, there are many variants of mov i.e. 
 case 0x89: /* mov Gv, Ev */
 case 0xc7: /* mov Ev, Iv */
 case 0x8b: /* mov Ev, Gv */
 case 0x8e: /* mov seg, Gv */

which one do you think will be called when "mov %eax, %eax" instruction is translated. 
I printed the value of modrm inside the case 0x89 but the value remains the same whether I use %eax or %ebx. 

Secondly, How can I extract the source and destination registers from modrm.

I will really appreciate your help.

Thanks,
Atif

On 4/6/07, Eduardo Felipe <address@hidden> wrote:

Hi,

Your should create a new helper function in \target-i386\helper.c to perform whatever you want QEMU to do when movl %eax,%eax is found.

To invoke that function create a new opcode in \target-i386\op.c. That opcode should only call your helper function.

Finally, modify \target-i386\translate.c to generate your opcode when movl %eax,%eax is translated. Look for the string 0x89, you can find out target and source registers of the move operation from variable modrm, so only %eax is considered.

Regards,
Eduardo