From: don@DonHopkins.com (Don Hopkins)
Subject: [TUHS] origins of void* -- Apology!
Date: Wed, 8 Nov 2017 21:43:00 +0100 [thread overview]
Message-ID: <F9685E8B-F048-4498-B4AF-78B07A3CCF49@gmail.com> (raw)
In-Reply-To: <CADFF66F-2291-43E4-A293-A96775829F28@gmail.com>
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> The PDP-10 had arbitrarily sized byte pointers! Did anybody ever implement a C compiler on that hardware?
>
> https://stackoverflow.com/questions/3153141/defining-a-byte-in-c <https://stackoverflow.com/questions/3153141/defining-a-byte-in-c>
>
> https://en.wikipedia.org/wiki/36-bit <https://en.wikipedia.org/wiki/36-bit>
>
> As DIGEX teased the VAX weenies at DECUS:
>
> “If you’re not playing with 36 bits, you’re not playing with a full DEC!"
>
> -Don
>
Re: PDP-10 backend for gcc
https://gcc.gnu.org/ml/gcc/2000-09/msg00073.html <https://gcc.gnu.org/ml/gcc/2000-09/msg00073.html>
ftp://kermit.columbia.edu/kermit/dec20/assembler-guide.txt <ftp://kermit.columbia.edu/kermit/dec20/assembler-guide.txt>
2.12. Byte Instructions
In the PDP-10 a "byte" is some number of contiguous bits within one word. A
byte pointer is a word that describes the byte. There are three parts to the
description of a byte: the word (i.e., address) in which the byte occurs, the
position of the byte within the word, and the length of the byte.
A byte pointer has the following format:
Bit 000000 000011 1 1 1111 112222222222333333
Position 012345 678901 2 3 4567 890123456789012345
_________________________________________
| | | | | | |
| POS | SIZE |U|I| X | Y |
|______|______|_|_|____|__________________|
- POS is the byte position: the number of bits remaining in the word
to the right of the byte.
- SIZE is the byte size in bits.
- The U field is reserved for future use and must be zero.
- I, X, and Y are the same as in an instruction.
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next prev parent reply other threads:[~2017-11-08 20:43 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-04 10:19 [TUHS] origins of void* Paul Ruizendaal
2017-11-05 9:48 ` Clem Cole
2017-11-05 10:06 ` arnold
2017-11-05 13:20 ` Ron Natalie
2017-11-05 15:14 ` Warner Losh
2017-11-05 17:53 ` Clem cole
2017-11-05 18:29 ` Steve Simon
2017-11-05 20:12 ` Clem cole
2017-11-05 21:08 ` Chet Ramey
2017-11-05 21:38 ` Clem cole
2017-11-05 21:53 ` Steve Simon
2017-11-05 20:44 ` Paul Ruizendaal
2017-11-05 21:06 ` Warner Losh
2017-11-06 7:24 ` arnold
2017-11-06 15:02 ` Warner Losh
2017-11-06 21:46 ` [TUHS] origins of void* -- Apology! Steve Johnson
2017-11-06 22:18 ` Warner Losh
2017-11-07 0:25 ` Ron Natalie
2017-11-07 0:34 ` Arthur Krewat
2017-11-07 0:36 ` Ron Natalie
2017-11-07 1:09 ` Bakul Shah
2017-11-07 1:55 ` Ron Natalie
2017-11-08 17:44 ` Ralph Corderoy
2017-11-08 19:56 ` Ron Natalie
2017-11-08 20:39 ` Don Hopkins
2017-11-08 20:42 ` Ron Natalie
2017-11-08 20:47 ` Don Hopkins
2017-11-08 20:48 ` Don Hopkins
2017-11-08 20:43 ` Don Hopkins [this message]
2017-11-08 20:43 ` Clem Cole
2017-11-08 20:45 ` Warner Losh
2017-11-09 6:33 ` Lars Brinkhoff
2017-11-08 20:50 ` Steve Nickolas
2017-11-08 21:25 ` Bakul Shah
2017-11-09 6:37 ` Lars Brinkhoff
2017-11-09 7:14 ` Don Hopkins
2017-11-09 7:44 ` Lars Brinkhoff
2017-11-10 23:43 ` [TUHS] PowerPC, bit twiddling - was " Toby Thain
2017-11-10 23:58 ` Ralph Corderoy
2017-11-07 15:34 [TUHS] " Nelson H. F. Beebe
2017-11-08 12:48 ` Tony Finch
2017-11-08 13:36 ` Otto Moerbeek
2017-11-08 16:03 ` Warner Losh
2017-11-08 16:07 Nemo
2017-11-08 16:12 ` Warner Losh
2017-11-08 19:59 ` Ron Natalie
2017-11-08 23:33 ` Steffen Nurpmeso
2017-11-09 1:35 ` Steve Johnson
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