diff options
Diffstat (limited to 'include/fpu')
| -rw-r--r-- | include/fpu/softfloat-helpers.h | 11 | ||||
| -rw-r--r-- | include/fpu/softfloat-types.h | 38 |
2 files changed, 49 insertions, 0 deletions
diff --git a/include/fpu/softfloat-helpers.h b/include/fpu/softfloat-helpers.h index 94cbe073ec..453188de70 100644 --- a/include/fpu/softfloat-helpers.h +++ b/include/fpu/softfloat-helpers.h @@ -75,6 +75,12 @@ static inline void set_floatx80_rounding_precision(FloatX80RoundPrec val, status->floatx80_rounding_precision = val; } +static inline void set_float_2nan_prop_rule(Float2NaNPropRule rule, + float_status *status) +{ + status->float_2nan_prop_rule = rule; +} + static inline void set_flush_to_zero(bool val, float_status *status) { status->flush_to_zero = val; @@ -126,6 +132,11 @@ get_floatx80_rounding_precision(float_status *status) return status->floatx80_rounding_precision; } +static inline Float2NaNPropRule get_float_2nan_prop_rule(float_status *status) +{ + return status->float_2nan_prop_rule; +} + static inline bool get_flush_to_zero(float_status *status) { return status->flush_to_zero; diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h index 0884ec4ef7..8f39691dfd 100644 --- a/include/fpu/softfloat-types.h +++ b/include/fpu/softfloat-types.h @@ -171,6 +171,43 @@ typedef enum __attribute__((__packed__)) { } FloatX80RoundPrec; /* + * 2-input NaN propagation rule. Individual architectures have + * different rules for which input NaN is propagated to the output + * when there is more than one NaN on the input. + * + * If default_nan_mode is enabled then it is valid not to set a + * NaN propagation rule, because the softfloat code guarantees + * not to try to pick a NaN to propagate in default NaN mode. + * When not in default-NaN mode, it is an error for the target + * not to set the rule in float_status, and we will assert if + * we need to handle an input NaN and no rule was selected. + */ +typedef enum __attribute__((__packed__)) { + /* No propagation rule specified */ + float_2nan_prop_none = 0, + /* Prefer SNaN over QNaN, then operand A over B */ + float_2nan_prop_s_ab, + /* Prefer SNaN over QNaN, then operand B over A */ + float_2nan_prop_s_ba, + /* Prefer A over B regardless of SNaN vs QNaN */ + float_2nan_prop_ab, + /* Prefer B over A regardless of SNaN vs QNaN */ + float_2nan_prop_ba, + /* + * This implements x87 NaN propagation rules: + * SNaN + QNaN => return the QNaN + * two SNaNs => return the one with the larger significand, silenced + * two QNaNs => return the one with the larger significand + * SNaN and a non-NaN => return the SNaN, silenced + * QNaN and a non-NaN => return the QNaN + * + * If we get down to comparing significands and they are the same, + * return the NaN with the positive sign bit (if any). + */ + float_2nan_prop_x87, +} Float2NaNPropRule; + +/* * Floating Point Status. Individual architectures may maintain * several versions of float_status for different functions. The * correct status for the operation is then passed by reference to @@ -181,6 +218,7 @@ typedef struct float_status { uint16_t float_exception_flags; FloatRoundMode float_rounding_mode; FloatX80RoundPrec floatx80_rounding_precision; + Float2NaNPropRule float_2nan_prop_rule; bool tininess_before_rounding; /* should denormalised results go to zero and set the inexact flag? */ bool flush_to_zero; |