From nobody Fri Mar 31 22:28:01 2023 X-Original-To: arch@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4PpFKv1HJmz43LJP for ; Fri, 31 Mar 2023 22:28:03 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4PpFKv0fPrz3rvL; Fri, 31 Mar 2023 22:28:03 +0000 (UTC) (envelope-from jhb@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1680301683; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=h4NjrtA2O2g2ZC3gHx/m5kYM0xVJ3S6VNJmw0R9lsr8=; b=tHrYTHkcmjbOEdxHMaUImNVTV+GBpTiSuOaIU/tXObSeOYW32SgcpHFto2jaiVAQgtPP4J IDMsRjasYFbYpDHK8aq5zmxbuPN91uuckUHBUwpbSWNXnbNdU2vOtDD2elzEjeif6yaI9D E5vMQl0/Ol+8UZ3X/NCcP0V8pSabUefI2W+3b+gb6d4c12ttqoOJiZ/X7mxBVH1fnSvAdZ fDMu+ZuE9f3gEJkoc/e1Zi8fb5/DyivEhFohM2qXGPmPfbJJuSdnf1MYprzmaKJyxRS/nL 0PYRODg3/G3KOZ2d8mjKS/O3brI8lOCFe5Ih5qQahjBrJOWgRMvOEM4/A9xfGA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1680301683; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=h4NjrtA2O2g2ZC3gHx/m5kYM0xVJ3S6VNJmw0R9lsr8=; b=pKiWZ978eWyY/6m9l78JdTjJeOXnFwetLT8bMTrS5ia7/ZhglTpzdlPc8sN2zkzJypXfXY H+poJVTEe9UkHym9Syrho2WBBPATd9nFL8U7v65hOKgEXjxQzOq8EiD/uNUS7V3Hs7HsTC XZhRl295HCFdbSMZEqsjn3Kls8xOkSehJNoAWwxYoMZQN+Qy9m6x9ulOhHXQFCK+noO9xV 5ZHMvegsHjMYFhjmBtXSMMo96udEwcH8fFIwxgulHXyoRAIROVVEqroeVV3BX+HAXLs9/R xCzBX0RO8htK+OMzFODJ8XCN042BY3JBe9w5kuQB/fm7K8ahLwQX2Xk0AGFaFg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1680301683; a=rsa-sha256; cv=none; b=rdlQxH0qUMz/rM03Il41oPOT8+3wA6d57poKo0YgpYF0fX/Ov0MydDU6QT8qziaBUIg5Ie FOVMQkr8RWyBFSspy19xyNKZ0k8XyxN1rfQ67Tt6JOBwVfy44pqah8glxcR63pm5N02QLR 9ESu1f9jNEnaUyN7tVQgQboanDPrgWHSqHicMNZA5qb9ze6T4uZuLiOfyPh7TseqnK53bp 0DZcskwu7e91sJDoc4N+VgZsjTB2HkpT26XrYy7Hatpry0tFnCye6WUpjOn/JiIEWISW6p eyIN0KrM+HwJ4uiL6i4qUIPKKs7eq6BucByAaVDneonM4HotRTpyA8xqbDBXTw== Received: from [IPV6:2601:648:8680:16b0:1094:688c:52c:68a7] (unknown [IPv6:2601:648:8680:16b0:1094:688c:52c:68a7]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id 4PpFKt4zRzzFc8; Fri, 31 Mar 2023 22:28:02 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Message-ID: <0146d3b2-2dd2-0968-4e54-d5afc01c0854@FreeBSD.org> Date: Fri, 31 Mar 2023 15:28:01 -0700 List-Id: Discussion related to FreeBSD architecture List-Archive: https://lists.freebsd.org/archives/freebsd-arch List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arch@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: Deprecate/remove riscv64sf Content-Language: en-US To: Ruslan Bukin Cc: arch@freebsd.org References: <629bf85d-4d48-17f5-cb26-dfd29f7e6ff7@FreeBSD.org> From: John Baldwin In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ThisMailContainsUnwantedMimeParts: N On 3/31/23 1:11 PM, Ruslan Bukin wrote: > On Wed, Mar 29, 2023 at 11:17:21AM -0700, John Baldwin wrote: >> Is anyone using riscv64sf? All of the existing RISC-V boards include hard-float >> support as well as QEMU. The FPGA cores we use at Cambridge also all support >> hard-float. My understanding is that glibc doesn't bother supporting soft-float >> on RV64. If no one is using it (and has no plans to use it), then I propose >> we drop it in 14.0 and save one more buildworld from make tinderbox. >> > > The idea behind this was to support extensibility of architecture (which is one of the key features of RISC-V). So if F,D,Q extension is not implemented, then riscv64sf could be used. It could be that those times some simulators/emulators did not support these extensions, so riscv64sf created (I could not remember). > It could be some of new (synthesized) hardware or new emulators won't have support for this straight away. So in research&development perspective it could be useful, in real life probably not for 64 bit. I think when riscv64sf was added we were less certain about how prevalent floating point support would be for RISC-V. For example, at Cambridge our MIPS cores did not always include floating point hardware. However, I think in practice FP is always available for 64-bit RISC-V cores. Even open source cores for 64-bit RISC-V include FP support. It's true that cores targetted at more embedded use cases might not include FP, but I don't think FreeBSD is targeted at those cores (nor really Linux for that matter). -- John Baldwin