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Re: [patch/rfc] Add host's floatformat

[picking up a really old thread]

Really, I don't see why this is better than a hardwired table
mapping CPU to floating point format.

Because most FPUs are IEEE, so except for the ones that aren't, it
will auto-detect the FPU type.  Having a table means that CPUs default
to "broken", rather than defaulting to "probably works".

It also means we don't have to keep tweaking the table as people
change their minds about CPU naming schemes

This assume that the floatformat code works.

Below is a table generated by using floatformat to convert the double 1.0 into the corresponding architecture format. Notice the arm_ext_big / arm_littlebyte_bigword and double_big / double_littlebyte_bigword pairs:

3f800000                         floatformat_ieee_single_big
0000803f                         floatformat_ieee_single_little
3ff0000000000000                 floatformat_ieee_double_big
000000000000f03f                 floatformat_ieee_double_little
3ff0000000000000                 floatformat_ieee_double_littlebyte_bigword
0000000000000080ff3f             floatformat_i387_ext
3fff8000000000000000             floatformat_m88110_ext
3fff00008000000000000000         floatformat_m68881_ext
0000000000000080ff3f0000         floatformat_i960_ext
00003fff8000000000000000         floatformat_arm_ext_big
00003fff8000000000000000         floatformat_arm_ext_littlebyte_bigword
3ff00000000000000000000000000000 floatformat_m88110_ext_harris
3fffe000000000000000000000000000 floatformat_ia64_spill_big
00000000000000000000000000e0ff3f floatformat_ia64_spill_little
3fff0000000000000000000000000000 floatformat_ia64_quad_big
0000000000000000000000000000ff3f floatformat_ia64_quad_little

I'm withdrawing my patch. I'll instead fix this as MarkK suggested - local to GDB.


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