diff options
Diffstat (limited to 'target/mips/msa.c')
| -rw-r--r-- | target/mips/msa.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/target/mips/msa.c b/target/mips/msa.c index 61f1a9a..32c6acb 100644 --- a/target/mips/msa.c +++ b/target/mips/msa.c @@ -48,6 +48,35 @@ void msa_reset(CPUMIPSState *env) /* tininess detected after rounding.*/ set_float_detect_tininess(float_tininess_after_rounding, &env->active_tc.msa_fp_status); + /* + * MSACSR.FS detects tiny results to flush to zero before rounding + * (per "MIPS Architecture for Programmers Volume IV-j: The MIPS64 SIMD + * Architecture Module, Revision 1.1" section 3.5.4), even though it + * detects tininess after rounding for underflow purposes (section 3.4.2 + * table 3.3). + */ + set_float_ftz_detection(float_ftz_before_rounding, + &env->active_tc.msa_fp_status); + + /* + * According to MIPS specifications, if one of the two operands is + * a sNaN, a new qNaN has to be generated. This is done in + * floatXX_silence_nan(). For qNaN inputs the specifications + * says: "When possible, this QNaN result is one of the operand QNaN + * values." In practice it seems that most implementations choose + * the first operand if both operands are qNaN. In short this gives + * the following rules: + * 1. A if it is signaling + * 2. B if it is signaling + * 3. A (quiet) + * 4. B (quiet) + * A signaling NaN is always silenced before returning it. + */ + set_float_2nan_prop_rule(float_2nan_prop_s_ab, + &env->active_tc.msa_fp_status); + + set_float_3nan_prop_rule(float_3nan_prop_s_cab, + &env->active_tc.msa_fp_status); /* clear float_status exception flags */ set_float_exception_flags(0, &env->active_tc.msa_fp_status); @@ -57,4 +86,11 @@ void msa_reset(CPUMIPSState *env) /* set proper signanling bit meaning ("1" means "quiet") */ set_snan_bit_is_one(0, &env->active_tc.msa_fp_status); + + /* Inf * 0 + NaN returns the input NaN */ + set_float_infzeronan_rule(float_infzeronan_dnan_never, + &env->active_tc.msa_fp_status); + /* Default NaN: sign bit clear, frac msb set */ + set_float_default_nan_pattern(0b01000000, + &env->active_tc.msa_fp_status); } |