From: Andriy Gapon <avg@FreeBSD.org>
To: malc <av1474@comtv.ru>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?
Date: Mon, 08 Oct 2012 12:02:04 +0300 [thread overview]
Message-ID: <5072968C.60000@FreeBSD.org> (raw)
In-Reply-To: <alpine.LNX.2.00.1210081152040.2993@linmac>
on 08/10/2012 10:52 malc said the following:
> On Mon, 8 Oct 2012, Andriy Gapon wrote:
>
>>
>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
>> provides popcnt instruction. Qemu advertises availability of pocnt
>> to a guest as well. What I see in the guest that popcnt
>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
>> With %rdi and %rax operands the instruction worked fine though.
>>
>>
>
> Does following work?
It does! Thank you very much.
> diff --git a/target-i386/translate.c b/target-i386/translate.c
> index e896abf..c36cc3e 100644
> --- a/target-i386/translate.c
> +++ b/target-i386/translate.c
> @@ -7818,7 +7818,7 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
> goto illegal_op;
>
> modrm = cpu_ldub_code(cpu_single_env, s->pc++);
> - reg = ((modrm >> 3) & 7);
> + reg = ((modrm >> 3) & 7) | rex_r;
>
> if (s->prefix & PREFIX_DATA)
> ot = OT_WORD;
>
--
Andriy Gapon
next prev parent reply other threads:[~2012-10-08 9:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-07 23:12 [Qemu-devel] bug in popcnt emulation with some register operand(s)? Andriy Gapon
2012-10-08 7:52 ` malc
2012-10-08 9:02 ` Andriy Gapon [this message]
2012-10-10 21:03 ` Andriy Gapon
2012-10-10 21:09 ` malc
2012-10-14 10:25 ` Andriy Gapon
2012-10-14 10:56 ` malc
2012-10-14 11:01 ` Andriy Gapon
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