> The problem is that it thinks that it can use NaN as any other
> number, which is illegal on vax (but legal with IEEE fp).

Only for quiet NaNs.  VAX reserved operands are like IEEE signaling
NaNs; the VAX has nothing like IEEE's quiet NaNs.  (Ragge, I imagine
you know this; this is more for people who aren't entirely clear on the
differences between VAX fp and IEEE fp.)

This mismatch between what "NaN" converts to on the VAX (a reserved
operand) and what it converts to under IEEE (a quiet NaN) is the
problem here.  If "NaN" converted to a signaling NaN under IEEE, you'd
presumably get the same issues on IEEE-using machines too.

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