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Re: integer overflow in muli instruction

From: Bruno Haible
Subject: Re: integer overflow in muli instruction
Date: Tue, 23 Feb 2021 20:21:38 +0100
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Jose E. Marchesi wrote:
> So I think at this point we are good when it comes to detecting overflow
> in signed operations.

There is a problem, though: A literal that was printed cannot be parsed
when viewed as an expression:

(poke) .set obase 10
(poke) -2*0x4000000000000000
(poke) -9223372036854775808L
<stdin>:1:1: error: expression overflows

What's odd is that this works in base 16:

(poke) .set obase 16
(poke) -2*0x4000000000000000
(poke) 0x8000000000000000L

Apparently because in base 16, signed integers are printed as if they were
unsigned. (Not sure whether this is intentional?)


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