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
> 
> Avi Kivity (7):
>   KVM: x86 emulator: framework for streamlining arithmetic opcodes
>   KVM: x86 emulator: Support for declaring single operand fastops
>   KVM: x86 emulator: introduce NoWrite flag
>   KVM: x86 emulator: mark CMP, CMPS, SCAS, TEST as NoWrite
>   KVM: x86 emulator: convert NOT, NEG to fastop
>   KVM: x86 emulator: add macros for defining 2-operand fastop emulation
>   KVM: x86 emulator: convert basic ALU ops to fastop
> 
>  arch/x86/kvm/emulate.c | 215 
> +++++++++++++++++++++++++++----------------------
>  1 file changed, 120 insertions(+), 95 deletions(-)

Applied, thanks.

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