malloc impossible?
Doug Gwyn
gwyn at smoke.BRL.MIL
Fri Jan 13 02:21:24 AEST 1989
In article <15427 at mimsy.UUCP> chris at 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).
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