From: Richard Henderson <rth@twiddle.net>
To: Aurelien Jarno <aurelien@aurel32.net>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 4/5] tcg/i386: use movbe instruction in qemu_ldst routines
Date: Sun, 22 Dec 2013 08:52:58 -0800 [thread overview]
Message-ID: <52B718EA.10500@twiddle.net> (raw)
In-Reply-To: <1387644224-2404-5-git-send-email-aurelien@aurel32.net>
On 12/21/2013 08:43 AM, Aurelien Jarno wrote:
> +/* If bit_MOVBE is defined in cpuid.h (added in GCC version 4.6), we are
> + going to attempt to determine at runtime whether movbe is available. */
> +#if defined(CONFIG_CPUID_H) && defined(bit_MOVBE)
> +static bool have_movbe;
> +#else
> +# define have_movbe 0
> +#endif
> +
Good point about checking bit_MOVBE, I missed that in my version.
I do slightly prefer hoisting the mov opcode, as I do in my version.
I think that tidies the 32 and 64-bit paths a bit. Nothing can really help
adding extra conditionals to the 16-bit load paths though.
r~
next prev parent reply other threads:[~2013-12-22 16:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-21 16:43 [Qemu-devel] [PATCH 0/5] tcg/i386: use movbe instruction in qemu_ldst routines Aurelien Jarno
2013-12-21 16:43 ` [Qemu-devel] [PATCH 1/5] disas/i386.c: disassemble movbe instruction Aurelien Jarno
2013-12-22 16:43 ` Richard Henderson
2013-12-21 16:43 ` [Qemu-devel] [PATCH 2/5] tcg/i386: remove hardcoded P_REXW value Aurelien Jarno
2013-12-22 16:43 ` Richard Henderson
2013-12-21 16:43 ` [Qemu-devel] [PATCH 3/5] tcg/i386: add support for three-byte opcodes Aurelien Jarno
2013-12-22 16:46 ` Richard Henderson
2013-12-21 16:43 ` [Qemu-devel] [PATCH 4/5] tcg/i386: use movbe instruction in qemu_ldst routines Aurelien Jarno
2013-12-22 16:52 ` Richard Henderson [this message]
2013-12-21 16:43 ` [Qemu-devel] [PATCH 5/5] tcg/i386: cleanup useless #ifdef Aurelien Jarno
2013-12-22 16:44 ` Richard Henderson
2013-12-22 11:24 ` [Qemu-devel] [PATCH 0/5] tcg/i386: use movbe instruction in qemu_ldst routines Aurelien Jarno
2013-12-22 11:47 ` Aurelien Jarno
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