Re: [PATCH v3 0/7] Streamline arithmetic instruction emulation

[Gleb Natapov <gleb@redhat.com>]

On Fri, Jan 04, 2013 at 04:18:47PM +0200, Avi Kivity wrote:
> The current arithmetic instruction emulation is fairly clumsy: after
> decode, each instruction gets a switch (size), and for every size
> we fetch the operands, prepare flags, emulate the instruction, then store
> back the flags and operands.
> 
> This patchset simplifies things by moving everything into common code
> except the instruction itself.  All the pre- and post- processing is
> coded just once.  The per-instrution code looks like:
> 
>   add %bl, %al
>   ret
> 
>   add %bx, %ax
>   ret
> 
>   add %ebx, %eax
>   ret
> 
>   add %rbx, %rax
>   ret
> 
> The savings in size, for the ten instructions converted in this patchset,
> are fairly large:
> 
>    text	   data	    bss	    dec	    hex	filename
>   63724	      0	      0	  63724	   f8ec	arch/x86/kvm/emulate.o.before
>   61268	      0	      0	  61268	   ef54	arch/x86/kvm/emulate.o.after
> 
> - around 2500 bytes.
> 
> v3: fix reversed operand order in 2-operand macro
> 
> v2: rebased
> 
Acked-by: Gleb Natapov <gleb@redhat.com>

--
			Gleb.