The emulated (CONFIG_MATH_EMULATION_FULL)
PowerPC Floating Point instruction mtfsf
does not correctly copy bits from its source
register to the Floating Point Status and Register (FPSCR).
The error is in the preparation of the mask used to
select the bits to be copied from the source to the FPSCR.
Execution of the mtfsf instruction does not produce the same
results on a MPC8548 platform (emulated floating point)
as on MPC7410 or 440EP platforms (hardware floating point).
This error has been detected using a Freescale MPC8548
based platform and the patch below tested using that platform.
The patch is based on the patch(es) provided by
Gabriel Paubert and analysis by Gabriel, James Yang and David Laight.
Signed-off-by: Stephen Chivers <schivers@csc.com>
Signed-off-by: Gabriel Paubert <paubert@iram.es>
Tested-by: Stephen Chivers <schivers@csc.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The math emulation code is centered around a set of generic macros that
provide the core of the emulation that are shared by the various
architectures and other projects (like glibc). Each arch implements its
own sfp-machine.h to specific various arch specific details.
For historic reasons that are now lost the powerpc math-emu code had
its own version of the common headers. This moves us to using the
kernel generic version and thus getting fixes when those are updated.
Also cleaned up exception/error reporting from the FP emulation functions.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Towards the goal of having arch/powerpc not build anything over in arch/ppc
move math-emu over. Also, killed some references to arch/ppc/ in the
arch/powerpc Makefile which should belong in drivers/ when the particular
sub-arch's move over to arch/powerpc.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Stephen Chivers
Kumar Gala
Harvey Harrison