Saving FPU registers: fxam, tag word etc

[raymond]

in case other parts of the code have put valid entries inside

If that code is entirely yours, I still maintain that you should be aware if those other parts have left valid data. To be more precise, good programming would dictate that those other parts should never leave valid data if there is any possibility that it could be trashed by any other part of your code.

[jj2007]

in case other parts of the code have put valid entries inside

If that code is entirely yours, I still maintain that you should be aware if those other parts have left valid data. To be more precise, good programming would dictate that those other parts should never leave valid data if there is any possibility that it could be trashed by any other part of your code.

It boils down to the same behaviour as the Masm32 FloatToStr routine: ST5-ST7 will be trashed by float$ - if they are really needed, it's up to the calling routine to save and restore them. Checking inside float$ is a waste of 100+ cycles...

[raymond]

it's up to the calling routine to save and restore them. Checking inside float$ is a waste of 100+ cycles..

I support that 100%+ :clap: :clap:

[jj2007]

it's up to the calling routine to save and restore them. Checking inside float$ is a waste of 100+ cycles..

I support that 100%+ :clap: :clap:

Thanks, Raymond :bg

Although JimG also has a point here:

As a general purpose routine, I'm assuming the user might want to print out any fpu register for debugging purposes, and would be upset if anything about the fpu changed.

My current version of float$ will only trash the last two regs, ST6 and ST7 - I guess 99% of all code does not use them. It is a factor 3 faster than the Masm32 FloatToStr, but I am still fighting with a tiny little bug. We'll see :P