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Re: Ada bootstrap failure on ia64


Zack Weinberg wrote:
This is wrong.  Actually, I think *all* definitions of
WIDEST_HARDWARE_FP_SIZE are wrong.

WIDEST_HARDWARE_FP_SIZE was added about the time when soft-fp 128-bit long doubles were added to the sparc port.


Robert Dewar claimed at the time that the Ada standard required all FP operations to be performed in the widest available FP format, and if the widest format was a soft-fp format, then that was obviously very bad for Ada performance. So the Ada front end limits the largest FP format to the largest one that is available in hardware.

I don't know Ada, so I don't know if there is a better way to solve this.

It makes sense that WIDEST_HARDWARE_FP_SIZE should be the FP precision not the FP format size, but since we haven't made this distinction before, it isn't surprising that there is confusion here.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com



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