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Re: PATCH to c-commonc.c, preliminary for PR/3865 fix


Richard Henderson <rth@redhat.com> writes:

| On Tue, Aug 27, 2002 at 11:21:31AM +0200, Gabriel Dos Reis wrote:
| >  	* doc/cpp.texi (Common Predefined Macros): Document
| > 	__TARGET_BITS_ORDER__, __TARGET_BYTES_ORDER__,
| >  	__TARGET_INT_WORDS_ORDER__, __TARGET_FLOAT_WORDS_ORDER__,
| > 	__TARGET_FLOAT_FORMAT__, __TARGET_USES_VAX_F_FLOAT__,
| > 	__TARGET_USES_VAX_D_FLOAT__, __TARGET_USES_VAX_G_FLOAT__,
| > 	__TARGET_USES_VAX_H_FLOAT__.
| 
| Could you explain where you're going with this?

The _ORDER__ macros make it possible to define the appropriate bytes
for QNaNs, SNaNs and the minimum denormals.  See for example, use in
libstdc++-v3/include/std/std_limits.h
Later, when V3 will provide support for classification functions, they
will be essential in determining appropiate data types.

The _VAX_*_FLOAT__ are also essential on non-IEEE 754 plateforms where
there are a variety of formats possible (a typical example is
Tru64/Unix or VAXes where command-line options can switch betwen
G-format and D-format).

-- Gaby


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