From: Richard Henderson <rth@twiddle.net>
To: "Emilio G. Cota" <cota@braap.org>, qemu-devel@nongnu.org
Cc: mttcg@greensocs.com, Peter Maydell <peter.maydell@linaro.org>,
Alvise Rigo <a.rigo@virtualopensystems.com>,
Paolo Bonzini <pbonzini@redhat.com>,
alex.bennee@linaro.org,
Frederic Konrad <fred.konrad@greensocs.com>
Subject: Re: [Qemu-devel] [RFC 1/8] cputlb: add physical address to CPUTLBEntry
Date: Fri, 08 May 2015 14:51:58 -0700 [thread overview]
Message-ID: <554D2FFE.20204@twiddle.net> (raw)
In-Reply-To: <1431118934-20900-2-git-send-email-cota@braap.org>
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~
next prev parent reply other threads:[~2015-05-08 21:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-08 21:02 [Qemu-devel] [RFC 0/8] Helper-based Atomic Instruction Emulation (AIE) Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 1/8] cputlb: add physical address to CPUTLBEntry Emilio G. Cota
2015-05-08 21:51 ` Richard Henderson [this message]
2015-05-10 8:07 ` Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 2/8] softmmu: add helpers to get ld/st physical addresses Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 3/8] tiny_set: add module to test for membership in a tiny set of pointers Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 4/8] radix-tree: add generic lockless radix tree module Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 5/8] aie: add module for Atomic Instruction Emulation Emilio G. Cota
2015-05-08 22:41 ` Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 6/8] aie: add target helpers Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 7/8] target-arm: emulate atomic instructions using AIE Emilio G. Cota
2015-05-08 21:02 ` [Qemu-devel] [RFC 8/8] target-i386: " Emilio G. Cota
2015-05-11 16:01 ` [Qemu-devel] [RFC 0/8] Helper-based Atomic Instruction Emulation (AIE) Frederic Konrad
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