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sizeof(double) is not guaranteed to be 64bits #37

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mickjc750 opened this issue Aug 29, 2021 · 1 comment
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sizeof(double) is not guaranteed to be 64bits #37

mickjc750 opened this issue Aug 29, 2021 · 1 comment
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@mickjc750 @eyalroz
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resolved-on-develop A changeset fixing this issue has been commiutted to the development branch task

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@mickjc750
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On AVR, and most likely some other 8-bit platforms, double is only 32bit.
This breaks %e and %g (but not %f).
Ideally, it would be nice to provide some kind of %e %g functionality when double is 32bit, perhaps with reduced precision.
At a minimum, a build error should occur if %e and or %g is enabled on these platforms.
@eyalroz
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eyalroz commented Sep 5, 2021

Hmm, you're right about the size. The standard apparently allows for smaller doubles.

How come it doesn't break %f, I wonder?

Anyway, I'll need to go over the code and see.

@eyalroz eyalroz self-assigned this Sep 5, 2021
@eyalroz eyalroz added the task label Sep 6, 2021
eyalroz added a commit that referenced this issue Sep 20, 2021
@eyalroz
Fixes #37: Now supporting the possibility of double having 32 bits …
bd89cc7 
…(single-precision) rather than 64 bits (double precision).

* `double` type size is now checked indirectly via the number of mantissa digits.
* Now ensuring floating-point types are binary (as, technically, they could theoretically not be).
* Replaced some 64-bit-double-specific magic numbers with preprocessor-defined constants, depending on whether `double` is a 32 or 64-bit type.
* Now defining an unsigned integer type to correspond exactly to `double`.
* Some comment tweaks.
@eyalroz eyalroz added the resolved-on-develop A changeset fixing this issue has been commiutted to the development branch label Sep 20, 2021
eyalroz added a commit that referenced this issue Sep 27, 2021
@eyalroz
Fixes #37: Now supporting the possibility of double having 32 bits …
1336270 
…(single-precision) rather than 64 bits (double precision).

* `double` type size is now checked indirectly via the number of mantissa digits.
* Now ensuring floating-point types are binary (as, technically, they could theoretically not be).
* Replaced some 64-bit-double-specific magic numbers with preprocessor-defined constants, depending on whether `double` is a 32 or 64-bit type.
* Now defining an unsigned integer type to correspond exactly to `double`.
* Some comment tweaks.
@eyalroz eyalroz closed this as completed Oct 5, 2021
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