target-mips: Implement FCR31's R/W bitmask and related functionalities

This patch implements read and write access rules for Mips floating
point control and status register (FCR31). The change can be divided
into following parts:

- Add fields that will keep FCR31's R/W bitmask in procesor
  definitions and processor float_status structure.

- Add appropriate value for FCR31's R/W bitmask for each supported
  processor.

- Add function for setting snan_bit_is_one, and integrate it in
  appropriate places.

- Modify handling of CTC1 (case 31) instruction to use FCR31's R/W
  bitmask.

- Modify handling user mode executables for Mips, in relation to the
  bit EF_MIPS_NAN2008 from ELF header, that is in turn related to
  reading and writing to FCR31.

- Modify gdb behavior in relation to FCR31.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
This commit is contained in:
Aleksandar Markovic 2016-06-10 11:57:36 +02:00 committed by Leon Alrae
parent 87552089b6
commit 599bc5e89c
6 changed files with 56 additions and 19 deletions

View file

@ -111,6 +111,7 @@ struct CPUMIPSFPUContext {
#define FCR0_PRID 8
#define FCR0_REV 0
/* fcsr */
uint32_t fcr31_rw_bitmask;
uint32_t fcr31;
#define FCR31_ABS2008 19
#define FCR31_NAN2008 18
@ -853,10 +854,17 @@ static inline void restore_flush_mode(CPUMIPSState *env)
&env->active_fpu.fp_status);
}
static inline void restore_snan_bit_mode(CPUMIPSState *env)
{
set_snan_bit_is_one((env->active_fpu.fcr31 & (1 << FCR31_NAN2008)) == 0,
&env->active_fpu.fp_status);
}
static inline void restore_fp_status(CPUMIPSState *env)
{
restore_rounding_mode(env);
restore_flush_mode(env);
restore_snan_bit_mode(env);
}
static inline void restore_msa_fp_status(CPUMIPSState *env)