From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11238 Path: news.gmane.org!.POSTED!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: [MUSL] microMIPS32R2 O32 port Date: Thu, 13 Apr 2017 11:00:37 +0200 Message-ID: <20170413090036.GH2082@port70.net> References: <20170406161804.GM17319@brightrain.aerifal.cx> <20170407141941.GQ17319@brightrain.aerifal.cx> <20170412192535.GG2082@port70.net> <20170412202721.GY17319@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1492074060 5495 195.159.176.226 (13 Apr 2017 09:01:00 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 13 Apr 2017 09:01:00 +0000 (UTC) User-Agent: Mutt/1.6.0 (2016-04-01) Cc: Andre McCurdy , Jaydeep Patil To: musl@lists.openwall.com Original-X-From: musl-return-11253-gllmg-musl=m.gmane.org@lists.openwall.com Thu Apr 13 11:00:51 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1cyacU-000159-4c for gllmg-musl@m.gmane.org; Thu, 13 Apr 2017 11:00:50 +0200 Original-Received: (qmail 7319 invoked by uid 550); 13 Apr 2017 09:00:49 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 7301 invoked from network); 13 Apr 2017 09:00:48 -0000 Mail-Followup-To: musl@lists.openwall.com, Andre McCurdy , Jaydeep Patil Content-Disposition: inline In-Reply-To: Xref: news.gmane.org gmane.linux.lib.musl.general:11238 Archived-At: * Jaydeep Patil [2017-04-13 04:29:10 +0000]: > With this branch (micromips32r2_v2) we are supporting microMIPS cores tha= t co-exist with MIPS. The MUSL library must be built with -minterlink-compr= essed option as there are couple of hand-written MIPS only functions. For m= icroMIPS only cores we will create a different subarch. >=20 ok the _v2 branch makes sense to me (the patch is sufficiently small that you can send it to the list) i think i was looking at _v1 before > >-----Original Message----- > >From: Andre McCurdy [mailto:armccurdy@gmail.com] > >Sent: 13 April 2017 AM 03:17 > >To: musl@lists.openwall.com > >Cc: Jaydeep Patil > >Subject: Re: [musl] [MUSL] microMIPS32R2 O32 port > > > >On Wed, Apr 12, 2017 at 1:27 PM, Rich Felker wrote: > >> On Wed, Apr 12, 2017 at 09:25:35PM +0200, Szabolcs Nagy wrote: > >>> * Jaydeep Patil [2017-04-12 11:54:10 +0000= ]: > >>> > Hi Rich, > >>> > > >>> > We can reuse existing MIPS code for microMIPS. There are places whe= re > >we read from $ra must be compiled for MIPS. > >>> > Please refer to https://github.com/JaydeepIMG/musl- > >1/tree/micromips32r2_v2 for modifications. > >>> > > >>> > >>> is micromips a different encoding for mips instructions that works on > >>> some cpus but not others? > >> > >> Yes, it's something like thumb or thumb2 on arm, or the riscv > >> compressed isa. What I'm not clear on is whether there are > >> micromips-only cpu models that can't execute normal mips. > > > >According to: > > > > https://imagination-technologies-cloudfront- > >assets.s3.amazonaws.com/documentation/MIPS_Architecture_microMIPS32 > >_InstructionSet_AFP_P_MD00582_06.04.pdf > > > >"microMIPS is also an alternative to the MIPS=AE instruction encoding an= d can > >be implemented in parallel or stand-alone." > > > >"If only one ISA mode exists (either MIPS or microMIPS) then this mode > >switch mechanism does not exist" > > > >> If so we probably need the ability to build musl as micromips, but as > >> long as cpus which support both support interworking (calls between > >> the two type of code in the same process) reasonably, I don't think > >> there's any reason to consider it a different subarch. > >> > >> If not (that is, if all cpus that support micromips also support the > >> normal mips isa) then I fail to see why there's any need to compile > >> musl's asm files as micromips. They're not size or performance > >> bottlenecks. > >> > >> Rich