From: Richard Henderson <richard.henderson@linaro.org>
To: "Emilio G. Cota" <cota@braap.org>,
"Alex Bennée" <alex.bennee@linaro.org>
Cc: laurent.desnogues@gmail.com,
Peter Maydell <peter.maydell@linaro.org>,
qemu-devel@nongnu.org, Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [RFC PATCH] fpu: add compile time check for old glibc/libm and fma
Date: Fri, 21 Dec 2018 14:01:02 -0800 [thread overview]
Message-ID: <72dff278-24d4-61db-3b49-a50a5aec6448@linaro.org> (raw)
In-Reply-To: <20181221193037.GB11197@flamenco>
On 12/21/18 11:30 AM, Emilio G. Cota wrote:
> + ua.s = 0x0020000000000001;
> + ub.s = 0x3ca0000000000000;
> + uc.s = 0x0020000000000000;
> + ur.h = fma(ua.h, ub.h, uc.h);
> + if (ur.s != 0x0020000000000001) {
Forgot your ull's, but otherwise ok.
In email to Alex, I did wonder if we should check for fma hardware (at least on
x86). Without a hardware insn, the libm routine is probably no faster than
softmmu.
r~
next prev parent reply other threads:[~2018-12-21 22:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-20 11:10 [Qemu-devel] [RFC PATCH] fpu: add compile time check for old glibc/libm and fma Alex Bennée
2018-12-20 13:10 ` Aleksandar Markovic
2018-12-21 14:14 ` Laurent Desnogues
2018-12-21 19:30 ` Emilio G. Cota
2018-12-21 22:01 ` Richard Henderson [this message]
2019-01-07 11:50 ` Alex Bennée
2019-01-07 12:42 ` Alex Bennée
2018-12-22 6:40 ` Aleksandar Markovic
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