[Lightning] Re: Updates for x86_64

[Paolo Bonzini]

On 08/24/2010 01:12 AM, Paulo César Pereira de Andrade wrote:
>   Patch1 is a clear typo and should be trivial.

Ok.

>   Patch2 changes JIT_REXTMP to %r11, so that, when calling a function
> with 6 integer arguments, it will not clobber the 6th argument in the
> last moment, due to putting the function pointer on it.
>
>   /* Used to implement ldc, stc, ... */
>   #define JIT_CAN_16 0
> -#define JIT_REXTMP             _R9D
> +#define JIT_REXTMP             _R11D
>
>   #define JIT_R_NUM             3
>   #define JIT_R(i)                ((i) == 0 ? _EAX : _R9D + (i))

Doesn't this mean JIT_R2 overlaps JIT_REXTMP?  Please redo the patch 
using %r12, and at the same time moving V1/V2 to r13/r14.

>   Patch3 defines symbolic names for extra SSE2 %xmmN registers, and
> sets JIT_FPTMP to the topmost one.

Ok.

>   Patch4 increases JIT_V_NUM to 5, and make %r14 and %r15 available,
> at the cost of needing to also save them. They are callee save registers
> in the abi.

I'd rather skip this one, 3 callee-save register are often enough.  %r14 
is going to be used anyway for V2 after you redo patch 2.

>   Patch5 adds safety check on number of integer or float arguments
> being passed to a function, and also increases the number of float
> register arguments to 8. Also, it defines JIT_RA_NUM and JIT_FA_NUM
> that matches the number of integer and float register arguments.
>
>   Patch6 also changes the mapping of JIT_R(num) and JIT_V(num), as well
> as JIT_REXTMP to use the 64 bits defines, so that it will not trigger
> an JITFAIL on jit_getarg_l and jit_getarg_ul for example, due to _rC
> telling it is a 32 bits registers. This is only an issue when
> _ASM_SAFETY is defined.

Both look fine.

Paolo