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From: Michael Morrell <mmorrell@tachyum.com>
To: Richard Henderson <richard.henderson@linaro.org>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: RE: [PATCH 03/11] softfloat: Introduce float_flag_inorm_denormal
Date: Wed, 14 Jul 2021 16:44:57 +0000	[thread overview]
Message-ID: <eca2d26624004ddea64c11b725c5f163@tachyum.com> (raw)
In-Reply-To: <c46f86e5-ab9e-1f64-f01d-7ec98413f1c5@linaro.org>

Just curious.  What's the expected timeline to get these denormal patches in the tree?

-----Original Message-----
From: Richard Henderson <richard.henderson@linaro.org> 
Sent: Saturday, May 29, 2021 8:21 AM
To: Michael Morrell <mmorrell@tachyum.com>; qemu-devel@nongnu.org
Cc: alex.bennee@linaro.org
Subject: Re: [PATCH 03/11] softfloat: Introduce float_flag_inorm_denormal

On 5/28/21 10:41 AM, Michael Morrell wrote:
> I'm probably missing something, but why do we need both "float_flag_inorm_denormal" and "float_flag_iflush_denormal"?
> 
> Couldn't the code that sets these flags set just a single flag for all 
> denormal inputs and the code that checks these flags check that single flag combined with the "flush_inputs_to_zero" flag to accomplish what the two separate "input denormal" flags do?

The thing that you're missing is that many guests leave the accumulated softfloat exceptions in the float_status structure until the guest FPSCR register is read. Unless the guest needs to raise an exception immediately, there's no reason to do otherwise.

With this setup, you have no temporal connection between "any denormal" and "flush-to-zero is set", thus two flags.


r~

  reply	other threads:[~2021-07-14 16:46 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27  4:13 [PATCH 00/11] softfloat: Improve denormal handling Richard Henderson
2021-05-27  4:13 ` [PATCH 01/11] softfloat: Rename float_flag_input_denormal to float_flag_iflush_denormal Richard Henderson
2021-06-07 15:16   ` Alex Bennée
2021-06-19 15:08   ` Philippe Mathieu-Daudé
2021-05-27  4:13 ` [PATCH 02/11] softfloat: Rename float_flag_output_denormal to float_flag_oflush_denormal Richard Henderson
2021-06-07 15:16   ` Alex Bennée
2021-06-19 15:08   ` Philippe Mathieu-Daudé
2021-05-27  4:13 ` [PATCH 03/11] softfloat: Introduce float_flag_inorm_denormal Richard Henderson
2021-05-28 17:41   ` Michael Morrell
2021-05-29 15:21     ` Richard Henderson
2021-07-14 16:44       ` Michael Morrell [this message]
2021-07-14 16:57         ` Richard Henderson
2021-07-14 17:50           ` Michael Morrell
2022-01-12  0:02             ` Michael Morrell
2021-06-07 15:35   ` Alex Bennée
2021-06-07 16:28     ` Alex Bennée
2021-06-07 16:41     ` Richard Henderson
2021-06-07 17:19       ` Alex Bennée
2021-06-07 20:52         ` Richard Henderson
2021-05-27  4:13 ` [PATCH 04/11] softfloat: Introduce float_flag_result_denormal Richard Henderson
2021-06-07 16:30   ` Alex Bennée
2021-06-19 15:10   ` Philippe Mathieu-Daudé
2021-05-27  4:13 ` [PATCH 05/11] target/i386: Use float_flag_inorm_denormal Richard Henderson
2021-06-19 18:41   ` Richard Henderson
2021-05-27  4:14 ` [PATCH 06/11] target/rx: Handle the FPSW.DN bit in helper_set_fpsw Richard Henderson
2021-05-28 15:34   ` Yoshinori Sato
2021-05-27  4:14 ` [PATCH 07/11] target/rx: Use FloatRoundMode " Richard Henderson
2021-05-28 15:35   ` Yoshinori Sato
2021-06-01  3:27   ` Philippe Mathieu-Daudé
2021-05-27  4:14 ` [PATCH 08/11] target/rx: Fix setting of FPSW.CE Richard Henderson
2021-05-28 15:35   ` Yoshinori Sato
2021-05-27  4:14 ` [PATCH 09/11] target/mips: Drop inline markers from msa_helper.c Richard Henderson
2021-06-01  3:27   ` Philippe Mathieu-Daudé
2021-05-27  4:14 ` [PATCH 10/11] target/mips: Do not check MSACSR_FS_MASK in update_msacsr Richard Henderson
2021-06-19 15:15   ` Philippe Mathieu-Daudé
2021-05-27  4:14 ` [PATCH 11/11] target/mips: Drop denormal operand to update_msacsr Richard Henderson
2021-06-01  3:29   ` Philippe Mathieu-Daudé
2021-06-07 16:31 ` [PATCH 00/11] softfloat: Improve denormal handling Alex Bennée

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