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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
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Subject: Re: 64-bit unsigned integer?
Date: Sun, 25 Feb 2018 17:35:32 +0100
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Date: 2018-02-25T17:35:32+01:00
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On 02/25/2018 01:54 PM, MM wrote:
> 
> I don't want to go the BigNum route - too heavyweight. Implementing it
> efficiently myself may require access to the processor's condition code
> registers, so this feels like an assembly language approach?

I'm sure the processor has operations that set the overflow flag. You could 
write machine-code insertions that invoke them and check the flag, but that 
doesn't seem like the best way to proceed.

I consider this a fault in the language design. There are two orthogonal 
concepts: whether the representation is signed or not, and whether overflow is 
detected or not. Mixing them together was a mistake.

GNAT had support for 64-bit integers before 64-bit processors were common, so it 
must have chained 2 32-bit integers together. One could hope that, now that 
64-bit processors are common, they'll support 128-bit integers.

-- 
Jeff Carter
"You empty-headed animal-food-trough wiper."
Monty Python & the Holy Grail
04