From mboxrd@z Thu Jan 1 00:00:00 1970 From: charles.unix.pro@gmail.com (Charles Anthony) Date: Wed, 18 Jan 2017 10:58:40 -0800 Subject: [TUHS] [TUHS} PDP-11, Unix, octal? In-Reply-To: <20170118184709.GC82883@server.rulingia.com> References: <50a7fbcbb6af280eb108fff1361c37ee1718bff0@webmail.yaccman.com> <86lgu8rjio.fsf@molnjunk.nocrew.org> <20170118184709.GC82883@server.rulingia.com> Message-ID: On Wed, Jan 18, 2017 at 10:47 AM, Peter Jeremy wrote: > On 2017-Jan-18 07:04:31 +0100, Lars Brinkhoff wrote: > >The PDP-10 did not have a fixed byte size. Were there any 9-bit > >machines? > > The Honeywell 6000 series (aka 66/DPS, a rebadged GE 6xx series) was > 36-bit and supported either 6-bit or 9-bit characters. I don't recall > how you selected which you were using but I recall both Pascal and APL > used the 9-bit byte. > > The [EIS] instruction set supported 4, 6 and 9 bit operands; it was a matter of which instructions you used. For pl1, the instructions generated were driven by the DCLs; for Pascal and APL, [I would guess] that the compiler/interpreter writers defined character size to be 9 bits and generated the 9 bit variants of the instructions. Move 9 6-bit bytes starting at the 3rd byte in the word, convert to 4 bit bytes in some signed manner, and store as 10 4-bit bytes starting at offset 6. MLR ,,400 move with sign captured ADSC6 FLD1,3,9 sending descriptor ADSC4 FLD2,6,10 receiving descriptor -- Charles -------------- next part -------------- An HTML attachment was scrubbed... URL: