From: "Emilio G. Cota" <cota@braap.org>
To: "Alex Bennée" <alex.bennee@linaro.org>
Cc: peter.maydell@linaro.org, richard.henderson@linaro.org,
Peter Crosthwaite <crosthwaite.peter@gmail.com>,
Riku Voipio <riku.voipio@iki.fi>,
qemu-devel@nongnu.org, Laurent Vivier <laurent@vivier.eu>,
"open list:ARM" <qemu-arm@nongnu.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Aurelien Jarno <aurelien@aurel32.net>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [Qemu-devel] [PATCH] fpu/softfloat: use hardware sqrt if we can (EXPERIMENT!)
Date: Wed, 21 Mar 2018 16:16:51 -0400 [thread overview]
Message-ID: <20180321201651.GA32458@flamenco> (raw)
In-Reply-To: <20180220210137.18018-1-alex.bennee@linaro.org>
On Tue, Feb 20, 2018 at 21:01:37 +0000, Alex Bennée wrote:
> This is an attempt to save some of the cost of sqrt by using the
> inbuilt support of the host hardware. The idea is assuming we start
> with a valid input we can use the hardware. If any tininess issues
> occur this will trip and FPU exception where:
>
> - we turn off cpu->use_host_fpu
> - mask the FPU exceptions
> - return to what we were doing
Please see this thread for an alternative approach:
[Qemu-devel] [PATCH v1 00/14] fp-test + hostfloat
https://lists.gnu.org/archive/html/qemu-devel/2018-03/msg05908.html
Emilio
next prev parent reply other threads:[~2018-03-21 20:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-06 16:47 [Qemu-devel] [PATCH v4 00/22] re-factor softfloat and add fp16 functions Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 01/22] fpu/softfloat: implement float16_squash_input_denormal Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 02/22] include/fpu/softfloat: remove USE_SOFTFLOAT_STRUCT_TYPES Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 03/22] fpu/softfloat-types: new header to prevent excessive re-builds Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 04/22] target/*/cpu.h: remove softfloat.h Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 05/22] include/fpu/softfloat: implement float16_abs helper Alex Bennée
2018-02-06 16:47 ` [Qemu-devel] [PATCH v4 06/22] include/fpu/softfloat: implement float16_chs helper Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 07/22] include/fpu/softfloat: implement float16_set_sign helper Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 08/22] include/fpu/softfloat: add some float16 constants Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 09/22] fpu/softfloat: improve comments on ARM NaN propagation Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 10/22] fpu/softfloat: move the extract functions to the top of the file Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 11/22] fpu/softfloat: define decompose structures Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 12/22] fpu/softfloat: re-factor add/sub Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 13/22] fpu/softfloat: re-factor mul Alex Bennée
2018-02-13 15:20 ` Peter Maydell
2018-02-13 15:39 ` Richard Henderson
2018-02-19 16:04 ` Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 14/22] fpu/softfloat: re-factor div Alex Bennée
2018-02-13 15:22 ` Peter Maydell
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 15/22] fpu/softfloat: re-factor muladd Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 16/22] fpu/softfloat: re-factor round_to_int Alex Bennée
2018-02-13 15:14 ` Peter Maydell
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 17/22] fpu/softfloat: re-factor float to int/uint Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 18/22] fpu/softfloat: re-factor int/uint to float Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 19/22] fpu/softfloat: re-factor scalbn Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 20/22] fpu/softfloat: re-factor minmax Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 21/22] fpu/softfloat: re-factor compare Alex Bennée
2018-02-06 16:48 ` [Qemu-devel] [PATCH v4 22/22] fpu/softfloat: re-factor sqrt Alex Bennée
2018-02-13 15:50 ` Peter Maydell
2018-02-13 16:23 ` Richard Henderson
2018-02-13 16:34 ` Peter Maydell
2018-02-20 21:01 ` [Qemu-devel] [PATCH] fpu/softfloat: use hardware sqrt if we can (EXPERIMENT!) Alex Bennée
2018-02-21 20:44 ` Alex Bennée
2018-03-21 20:16 ` Emilio G. Cota [this message]
2018-02-13 17:50 ` [Qemu-devel] [PATCH v4 22/22] fpu/softfloat: re-factor sqrt Richard Henderson
2018-02-06 17:42 ` [Qemu-devel] [PATCH v4 00/22] re-factor softfloat and add fp16 functions no-reply
2018-02-13 14:52 ` Peter Maydell
2018-02-17 13:23 ` Alex Bennée
2018-02-19 13:56 ` Peter Maydell
2018-02-22 1:23 ` Fam Zheng
2018-02-13 15:51 ` Peter Maydell
2018-02-13 17:31 ` Laurent Vivier
2018-02-20 12:43 ` Alex Bennée
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