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From: guy@rlgvax.UUCP (Guy Harris)
Newsgroups: net.lang.c
Subject: Re: sizeof
Message-ID: <411@rlgvax.UUCP>
Date: Fri, 1-Feb-85 17:34:27 EST
Article-I.D.: rlgvax.411
Posted: Fri Feb  1 17:34:27 1985
Date-Received: Sun, 3-Feb-85 09:41:41 EST
References: <7904@brl-tgr.ARPA>
Organization: CCI Office Systems Group, Reston, VA
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> Someone also said that ptr's to different objex may be different sizes.
> Where & why?

Where:

On a Zilog 8000 running in segmented mode (24-bit pointers).
On a Motorola 68000.
On an Intel 802*8[68] running large-model code.

Just because a machine supports large pointers doesn't mean that it
supports 32-bit arithmetic well.  The Z8000 probably does 32-bit
arithmetic 16 bits at a time.  The 68000 definitely does, and can't do
32-bit multiplies or divides conveniently at all.

Why:

Because it doesn't say anywhere that you can't.  Because you may not want
to pay the penalty for 32-bit arithmetic.

> I realize that a certain machine may desire this to make implementation
> as efficient as possible, but I think the designers should just bite
> the bullet and make all ptr's the same size.

On this point, I agree.  16-bit "int"s make techniques like using "malloc"
and "realloc" to grow a large table (used by such obscure programs as "nm")
lose big.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy