Re: [PATCH][PR 18702] Fix wrong output of x87 registers due to truncation to double on amd64

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Ruslan Kabatsayev <b7.10110111@gmail.com> [2015-12-04 19:09:46 +0300]:

> When `info float` is used on an AMD64 system, GDB prints floating-point
> values of x87 registers with raw contents like 0x361a867a8e0527397ce0 or
> 0xc4f988454a1ddd3cfdab wrongly. This happens due to truncation to double,
> after which the former becomes 0.0, and the latter becomes negative infinity.
> This is caused by failed detection of x86-64 host, which results in setting
> gdb_host_{float,double,long_double}_format to zeros.
> This commit fixes this misdetection, and adds a test to make sure future
> commits don't introduce a regression here.
> 
> gdb/ChangeLog:
> 
> 	* configure.host: Fix detection of x86_64 host when setting
> 	floatformats.
> 	* testsuite/gdb.arch/i386-float.S: Add a regression test for the fix.
> 	* testsuite/gdb.arch/i386-float.exp: Add checking of the test results.

There's a separate ChangeLog in the gdb/testsuite directory, so you
need to split your entry over these two files.  And remember files
names in the testsuite ChangeLog don't need to have the testsuite/
prefix.

Thanks,
Andrew