Pointer -> Long Conversion

[Clay Phipps]

Whether pointers should be sign-extended or not depends on the architecture
of the host machine.

Addresses in the ELXSI 6400 are *signed* 32-bit integers.
Therefore, they should be sign-extended when converted to 64-bit "long",
so that they retain their integral value in both sizes.

Although signed addresses are unconventional,
it turns out that they cause no problems whatsoever,
and they removed the need to perform 32-bit unsigned arithmetic
as a special case within the machine for address calculation.

If minus signs on addresses bother you, just print addresses in hexadecimal
(or octal, if you're an octopus :-), and you won't see them at all.

-- Clay Phipps

-- 
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