On Mon, May 16, 2016 at 04:12:44PM +0200, Aleksandar Markovic wrote: > From: Aleksandar Markovic <aleksandar.marko...@imgtec.com> > > New set of helpers for handling nan2008-syle versions of instructions > <CEIL|CVT|FLOOR|ROUND|TRUNC>.<L|W>.<S|D>, for Mips R6. > > All involved instructions have float operand and integer result. Their > core functionality is implemented via invocations of appropriate SoftFloat > functions. The problematic cases are when the operand is a NaN, and also > when the operand (float) is out of the range of the result. > > Here one can distinguish three cases: > > CASE MIPS-A: (FCR31.NAN2008 == 1) > > 1. Operand is a NaN, result should be 0; > 2. Operand is larger than INT_MAX, result should be INT_MAX; > 2. Operand is smaller than INT_MIN, result should be INT_MIN. > > CASE MIPS-B: (FCR31.NAN2008 == 0) > > 1. Operand is a NaN, result should be INT_MAX; > 2. Operand is larger than INT_MAX, result should be INT_MAX; > 2. Operand is smaller than INT_MIN, result should be INT_MAX. > > CASE SOFTFLOAT: > > 1. Operand is a NaN, result is INT_MAX; > 2. Operand is larger than INT_MAX, result is INT_MAX; > 2. Operand is smaller than INT_MIN, result is INT_MIN. > > It is interesting that neither MIPS-A nor MIPS-B desired behaviors > are in this sense identical to correspondent SoftFloat behavior. > > Current implementation of <CEIL|CVT|FLOOR|ROUND|TRUNC>.<L|W>.<S|D> > implements case MIPS-B. This patch relates to case MIPS-A. For case > MIPS-A, only return value for NaN-operands should be corrected after > appropriate SoftFloat library function is called. > > Related MSA instructions FTRUNC_S and FTINT_S already handle well > all cases, in the fashion similar to the code from this patch. > > Signed-off-by: Aleksandar Markovic <aleksandar.marko...@imgtec.com> > --- > target-mips/helper.h | 18 +-- > target-mips/op_helper.c | 369 > +++++++++++++++++++++++++++++++++++++++++++++--- > target-mips/translate.c | 122 +++++++++++++--- > 3 files changed, 461 insertions(+), 48 deletions(-)
Reviewed-by: Leon Alrae <leon.al...@imgtec.com>
