Re: is Vax addressing sane today

Lawrence D'Oliveiro wrote:

On Mon, 30 Sep 2024 11:15:05 +0300, Michael S wrote:
 

On Mon, 30 Sep 2024 01:28:42 -0000 (UTC)
Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
>

Also the fact that those “64-bit” APIs are not entirely “64-bit” ...

>
They are entirely 64-bit.

 <https://arstechnica.com/gadgets/2018/05/microsoft-learn-from-apple-ii/2/>:
      Another example; Win32 has a function for getting the size of a
     file. File sizes on Windows are limited to 2^64 bytes, and so they
     need a 64-bit integer to be expressed easily. But the API call to
     get the size of a file doesn't give you a 64-bit value. Instead,
     it gives you a pair of 32-bit values that have to be combined in a
     particular way. For 32-bit Windows, that's sort of understandable;
     32-bit Windows is, well, 32-bit, so you might not expect to be
     able to use 64-bit integers. But if you use the same API in 64-bit
     Windows, it still gives you the pair of numbers, rather than just
     a nice simple 64-bit number. While this made some kind of sense on
     32-bit Windows, it makes no sense at all on 64-bit Windows, since
     64-bit Windows can, by definition, use 64-bit numbers.

The first issue here is that the original API defined the return value as 32-bit, with an optional pointer to another variable to receive the high part, but they came up with the GetFileSizeEx() function decades ago, and that one gets the file size as a LARGE_INTEGER. Nobody uses anything else afair.
The second potential issue is with the definition of LARGE_INTEGER:
It is as as you say defined as a pair of 32-bit values, overlayed with a LONGLONG which can only work on a little-endian cpu since the low part is followed by the high, right?
Turns out every single Win32-system in existence/in regular use is little endian, so that is much less of a problem, and the docs tell you to
"The LARGE_INTEGER structure is actually a union. If your compiler has built-in support for 64-bit integers, use the QuadPart member to store the 64-bit integer. Otherwise, use the LowPart and HighPart members to store the 64-bit integer."
Yeah, not too pretty, but also not a real/important problem.
Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"