Word Size

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3 total messages Started by "THE DOCTOR." Sat, 07 Nov 1987 21:04

#3931

Author: "THE DOCTOR."
Date: Sat, 07 Nov 1987 21:04

13 lines
1312 bytes

How big is a word?  It seems to be common practice to implement INTEGERS
and CARDINALS as 16 bit words, and use LONGINT and LONGCARD for 32 bits.
If you're developing for a 32 bit computer, would it be appropriate to make
INTEGERS and CARDINALS 32 bits and either drop longs or make them 64 bits?
I notice that Wirth writes ~usually 16 bits~ which would seem to indicate
any word size would be appropriate.  This would raise some more portability
questions.

My own opinion would be to implement 32 bit integers and such, I just wanted
to hear some other opinions.

                                                        Tom Ruby
                                                     MSRS002@ECNCDC

Re: Word Size

#3938

Author: Alan Lovejoy
Date: Wed, 11 Nov 1987 16:17

18 lines
1603 bytes

In article <INFO-M2%87110717121037@UCF1VM> Info-Modula2 Distribution List <INFO-M2%UCF1VM.bitnet@jade.berkeley.edu> writes:
>How big is a word?  It seems to be common practice to implement INTEGERS
>and CARDINALS as 16 bit words, and use LONGINT and LONGCARD for 32 bits.
>
>My own opinion would be to implement 32 bit integers and such, I just wanted
>to hear some other opinions.

I think that 16 bits should be a *minimum* size for a word, and that 32
bits should be a *minimum* size for a longword.  Also SIZE(word) =
SIZE(CARDINAL) = SIZE(INTEGER) and SIZE(LONGWORD) = SIZE(LONGCARD) = 
SIZE(LONGINT).  If the instruction set of the machine supports longwords
greater than 32 bits, then a LONGWORD should be that size.  A WORD
should be an intermediate size between the shortest (byte?) and the
longest operand size.  LONGWORDs should be bigger than WORDs.  The BSI
M2 committee intends to have 3 standard sizes for all number types:
"short" "normal" and "long". A "SHORTWORD" is probably a byte.

--alan@pdn

Re: Word Size

#3942

Author: Markus Schaub
Date: Thu, 12 Nov 1987 20:18

16 lines
1430 bytes

In article <INFO-M2%87110717121037@UCF1VM>, MSRS002@ECNCDC.BITNET ("THE DOCTOR.") writes:
> If you're developing for a 32 bit computer, would it be appropriate to make
> INTEGERS and CARDINALS 32 bits and either drop longs or make them 64 bits?
> I notice that Wirth writes ~usually 16 bits~ which would seem to indicate

Although it is a 32-bit computer I would prefer CARDINAL and INTEGER types
with 16 bit, to save some space in RECORD and ARRAY definitions. If you
pack subranges ([0..255] -> 1 byte; [0..65535] -> 2 bytes) you can use 32 bit
CARDINALs and INTs. Finally on a 32 bit machine you have 32 x 32 bit
multiplications so why mess with 64 bit types and use the same techniques used
today for 32 bit types (routines in the run-time system).

-Markus
-- 
   //	Markus Schaub	uunet!nuchat!sugar!schaub	 (713) 523 8422
 \X/	c/o Interface Technologies Corp, 3336 Richmond #323, Houston Tx 77098

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