Re: [Qemu-devel] [RFC 1/8] cputlb: add physical address to CPUTLBEntry

[Richard Henderson]

On 05/08/2015 02:02 PM, Emilio G. Cota wrote:
> -#if HOST_LONG_BITS == 32 && TARGET_LONG_BITS == 32
> -#define CPU_TLB_ENTRY_BITS 4
> -#else
> +#if TARGET_LONG_BITS == 32
>  #define CPU_TLB_ENTRY_BITS 5
> +#else
> +#define CPU_TLB_ENTRY_BITS 6
>  #endif

Ouch.  24 of 64 wasted bytes for 64-bit?

I wonder if there's a better way we can encode this to avoid 3 copies of the
virtual address for read/write/code.  Or if we're better off using more than
one insn to multiply by a non-power-of-two.  Or if the hardware multiplier is
fast enough just multiply by the proper constant.


r~