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Re: Another thought on #o
- To: Robert W. Kerns <RWK at MIT-MC>
- Subject: Re: Another thought on #o
- From: Guy.Steele at CMU-10A
- Date: Wed, 5 Nov 80 16:23:00 GMT
- Cc: bug-lisp at MIT-MC
- In-reply-to: Robert W. Kerns's message of 1 Nov 80 12:41-EST
- Original-date: 5 November 1980 1123-EST (Wednesday)
"Under my proposal, the only truncation is that if you want
to type in a 32-bit number, you type in 32 bits."
How, pray tell, does one type precisely 32 bits in octal?
(Okay, so the VAX uses hex, but...)
But if you type in a 36-bit number (on the PDP-10), you said
that you wanted to get a fixnum, not a bignum. In order to
do this, you have to *know* that 36 bits is what you wanted.
By "truncation", I don't mean that any bits you typed are lost;
instead I mean that an arbitrary word length is somehow chosen,
which can cause odd things such as negative numbers to appear
if a large "unsigned" number is typed.
By the way, on the VAX should an unsigned number be 28 bits or 32 bits?
(Sorry, I meant 30 or 32.) In the one case you can't specify a full word
unsignedly; in the other you get a bignum.