Path: utzoo!attcan!uunet!lll-winken!ames!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: malloc impossible?
Message-ID: <9351@smoke.BRL.MIL>
Date: 12 Jan 89 16:21:24 GMT
References: <19@xenlink.UUCP> <225800106@uxe.cso.uiuc.edu> <310@twwells.uucp> <9342@smoke.BRL.MIL> <15427@mimsy.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 22

In article <15427@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>But I claim that, if the requirement for malloc() were dropped, one
>could implement C-minus-malloc on a machine that (say) required all
>floating point numbers to live in the floating-point address space,
>by having two stacks (one in the integer space and one in the fp space)
>and two data segments (likewise).

Assuming that integers could not also live in floating-point space,
C would not be implementable on such a hypothetical architecture.
Consider
	union	{
		double	d;
		int	i;
	}	u;
	u.d = 123.0;
	printf("%d\n", u.i);
This is required to work, although the specific value printed of course
depends on details of numeric representation on the specific system.
All data object types in C must be able to live in the same kind of space.
Whatever kind of space that is, is what one would parcel out via malloc().
Therefore malloc() is implementable if C is (at the very least, along the
lines I indicated in my previous example implementation).