Date: Sun, 26 Feb 2017 10:37:45 -0700 From: Warner Losh <imp@bsdimp.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Bruce Evans <brde@optusnet.com.au>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r314087 - head/sys/x86/x86 Message-ID: <CANCZdfrNKALZdrNSXUXKRS8hH_=LpQsP7pWD%2BRZbJM6cuTC=8A@mail.gmail.com> In-Reply-To: <20170226124445.GE2092@kib.kiev.ua> References: <201702220707.v1M7764i020598@repo.freebsd.org> <20170223053954.J1044@besplex.bde.org> <20170224125335.GV2092@kib.kiev.ua> <20170225130549.C1026@besplex.bde.org> <20170225101543.GC2092@kib.kiev.ua> <20170226013936.S856@besplex.bde.org> <20170226124445.GE2092@kib.kiev.ua>
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On Sun, Feb 26, 2017 at 5:44 AM, Konstantin Belousov <kostikbel@gmail.com> wrote: > On Sun, Feb 26, 2017 at 04:43:12AM +1100, Bruce Evans wrote: > 2.9 BSD was a port to PDP-11, AFAIK, with 16bit ints. A bit off topic, but 2BSD was basically[**] a continuation of Research Unix which started out life on the PDP-11 (well, OK, it started life in assembler on the PDP-7, but then was rewritten in C on the PDP-11). PDP-11 had 16-bit ints, 32-bit longs, 16-bit shorts, 16-bit pointers, 8-bit chars and 20-bit physical addresses. After 2.9, it also required weird things like separate I&D space where you could have a function pointer and a data pointer that had the same bit pattern, but referred to different objects because instruction space and address space were different (effectively giving 17-bits of address space, kinda). But you also had things like an overlay manager from hell that would page in different parts of the code if the program couldn't fit int 64k, and many of the limitations of the BSD 2.11 TCP stack were based on limitations of how deep you could do the overlays. It didn't have long longs. Or a compiler more modern than K&R[*]. Other than that, ULL vs explicit casts Warner [*] OK, gcc can produce pdp-11 output, even to this day. But it's far far to large to run on a pdp-11 natively. [**] Lots of cross pollination between BSD and Bell Labs is noted and documented extensively elsewhere.
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