From fc3c199facd60cc2facbfeee3e541e6aa6410f52 Mon Sep 17 00:00:00 2001 From: Faraz Shahbazker Date: Wed, 2 Feb 2022 11:17:24 +0100 Subject: [PATCH] sim: Add partial support for IEEE 754-2008 2022-02-01 Faraz Shahbazker sim/common/ChangeLog: * sim-fpu.c (sim_fpu_minmax_nan): New. (sim_fpu_max): Add variant behaviour for IEEE 754-2008. (sim_fpu_min): Likewise. (sim_fpu_is_un, sim_fpu_is_or): New. (sim_fpu_un, sim_fpu_or): New. (sim_fpu_is_ieee754_2008, sim_fpu_is_ieee754_1985): New. (sim_fpu_set_mode): New. (sim_fpu_classify): New. * sim-fpu.h (sim_fpu_minmax_nan): New declaration. (sim_fpu_un, sim_fpu_or): New declarations. (sim_fpu_is_un, sim_fpu_is_or): New declarations. (sim_fpu_mode): New enum. [sim_fpu_state](current_mode): New field. (sim_fpu_current_mode): New define. (sim_fpu_is_ieee754_2008): New declaration. (sim_fpu_is_ieee754_1985): New declaration. (sim_fpu_set_mode): New declaration. (sim_fpu_classify): New declaration. --- sim/common/sim-fpu.c | 110 +++++++++++++++++++++++++++++++++++++++++-- sim/common/sim-fpu.h | 26 +++++++++- 2 files changed, 131 insertions(+), 5 deletions(-) diff --git a/sim/common/sim-fpu.c b/sim/common/sim-fpu.c index 9174eaf17b4..ccaff9c7661 100644 --- a/sim/common/sim-fpu.c +++ b/sim/common/sim-fpu.c @@ -1005,6 +1005,30 @@ sim_fpu_op_nan (sim_fpu *f, const sim_fpu *l, const sim_fpu *r) return 0; } +/* NaN handling specific to min/max operations. */ + +INLINE_SIM_FPU (int) +sim_fpu_minmax_nan (sim_fpu *f, const sim_fpu *l, const sim_fpu *r) +{ + if (sim_fpu_is_snan (l) + || sim_fpu_is_snan (r) + || sim_fpu_is_ieee754_1985 ()) + return sim_fpu_op_nan (f, l, r); + else + /* if sim_fpu_is_ieee754_2008() + && ((sim_fpu_is_qnan (l) || sim_fpu_is_qnan (r))) */ + { + /* In IEEE754-2008: + "minNum/maxNum is ... the canonicalized number if one + operand is a number and the other a quiet NaN." */ + if (sim_fpu_is_qnan (l)) + *f = *r; + else /* if (sim_fpu_is_qnan (r)) */ + *f = *l; + return 0; + } +} + /* Arithmetic ops */ INLINE_SIM_FPU (int) @@ -1553,7 +1577,7 @@ sim_fpu_max (sim_fpu *f, const sim_fpu *r) { if (sim_fpu_is_nan (l) || sim_fpu_is_nan (r)) - return sim_fpu_op_nan (f, l, r); + return sim_fpu_minmax_nan (f, l, r); if (sim_fpu_is_infinity (l)) { if (sim_fpu_is_infinity (r) @@ -1616,7 +1640,7 @@ sim_fpu_min (sim_fpu *f, const sim_fpu *r) { if (sim_fpu_is_nan (l) || sim_fpu_is_nan (r)) - return sim_fpu_op_nan (f, l, r); + return sim_fpu_minmax_nan (f, l, r); if (sim_fpu_is_infinity (l)) { if (sim_fpu_is_infinity (r) @@ -1677,7 +1701,7 @@ INLINE_SIM_FPU (int) sim_fpu_neg (sim_fpu *f, const sim_fpu *r) { - if (sim_fpu_is_snan (r)) + if (sim_fpu_is_ieee754_1985 () && sim_fpu_is_snan (r)) { *f = *r; f->class = sim_fpu_class_qnan; @@ -1700,7 +1724,7 @@ sim_fpu_abs (sim_fpu *f, { *f = *r; f->sign = 0; - if (sim_fpu_is_snan (r)) + if (sim_fpu_is_ieee754_1985 () && sim_fpu_is_snan (r)) { f->class = sim_fpu_class_qnan; return sim_fpu_status_invalid_snan; @@ -2255,6 +2279,21 @@ sim_fpu_is_gt (const sim_fpu *l, const sim_fpu *r) return is; } +INLINE_SIM_FPU (int) +sim_fpu_is_un (const sim_fpu *l, const sim_fpu *r) +{ + int is; + sim_fpu_un (&is, l, r); + return is; +} + +INLINE_SIM_FPU (int) +sim_fpu_is_or (const sim_fpu *l, const sim_fpu *r) +{ + int is; + sim_fpu_or (&is, l, r); + return is; +} /* Compare operators */ @@ -2378,12 +2417,57 @@ sim_fpu_gt (int *is, return sim_fpu_lt (is, r, l); } +INLINE_SIM_FPU (int) +sim_fpu_un (int *is, const sim_fpu *l, const sim_fpu *r) +{ + if (sim_fpu_is_nan (l) || sim_fpu_is_nan (r)) + { + *is = 1; + return 0; + } + + *is = 0; + return 0; +} + +INLINE_SIM_FPU (int) +sim_fpu_or (int *is, const sim_fpu *l, const sim_fpu *r) +{ + sim_fpu_un (is, l, r); + + /* Invert result. */ + *is = !*is; + return 0; +} + +INLINE_SIM_FPU(int) +sim_fpu_classify (const sim_fpu *f) +{ + switch (f->class) + { + case sim_fpu_class_snan: return SIM_FPU_IS_SNAN; + case sim_fpu_class_qnan: return SIM_FPU_IS_QNAN; + case sim_fpu_class_infinity: + return f->sign ? SIM_FPU_IS_NINF : SIM_FPU_IS_PINF; + case sim_fpu_class_zero: + return f->sign ? SIM_FPU_IS_NZERO : SIM_FPU_IS_PZERO; + case sim_fpu_class_number: + return f->sign ? SIM_FPU_IS_NNUMBER : SIM_FPU_IS_PNUMBER; + case sim_fpu_class_denorm: + return f->sign ? SIM_FPU_IS_NDENORM : SIM_FPU_IS_PDENORM; + default: + fprintf (stderr, "Bad switch\n"); + abort (); + } + return 0; +} /* A number of useful constants */ #if EXTERN_SIM_FPU_P sim_fpu_state _sim_fpu = { .quiet_nan_inverted = false, + .current_mode = sim_fpu_ieee754_1985, }; const sim_fpu sim_fpu_zero = { @@ -2406,6 +2490,24 @@ const sim_fpu sim_fpu_max64 = { }; #endif +/* Specification swapping behaviour */ +INLINE_SIM_FPU (bool) +sim_fpu_is_ieee754_1985 (void) +{ + return (sim_fpu_current_mode == sim_fpu_ieee754_1985); +} + +INLINE_SIM_FPU (bool) +sim_fpu_is_ieee754_2008 (void) +{ + return (sim_fpu_current_mode == sim_fpu_ieee754_2008); +} + +INLINE_SIM_FPU (void) +sim_fpu_set_mode (const sim_fpu_mode m) +{ + sim_fpu_current_mode = m; +} /* For debugging */ diff --git a/sim/common/sim-fpu.h b/sim/common/sim-fpu.h index 2a141981687..a20b2861491 100644 --- a/sim/common/sim-fpu.h +++ b/sim/common/sim-fpu.h @@ -163,8 +163,15 @@ typedef enum FIXME: This state is global, but should be moved to SIM_CPU. */ +typedef enum +{ + sim_fpu_ieee754_1985, + sim_fpu_ieee754_2008, +} sim_fpu_mode; + typedef struct _sim_fpu_state { bool quiet_nan_inverted; /* Toggle quiet NaN semantics. */ + sim_fpu_mode current_mode; } sim_fpu_state; @@ -268,6 +275,8 @@ INLINE_SIM_FPU (int) sim_fpu_sqrt (sim_fpu *f, INLINE_SIM_FPU (int) sim_fpu_op_nan (sim_fpu *f, const sim_fpu *l, const sim_fpu *r); +INLINE_SIM_FPU (int) sim_fpu_minmax_nan (sim_fpu *f, + const sim_fpu *l, const sim_fpu *r); @@ -318,7 +327,8 @@ INLINE_SIM_FPU (double) sim_fpu_2d (const sim_fpu *d); /* INLINE_SIM_FPU (void) sim_fpu_f2 (sim_fpu *f, float s); */ INLINE_SIM_FPU (void) sim_fpu_d2 (sim_fpu *f, double d); - +/* IEEE754-2008 classifiction function. */ +INLINE_SIM_FPU (int) sim_fpu_classify (const sim_fpu *f); /* Specific number classes. @@ -367,7 +377,20 @@ INLINE_SIM_FPU (int) sim_fpu_is_ne (const sim_fpu *l, const sim_fpu *r); INLINE_SIM_FPU (int) sim_fpu_is_ge (const sim_fpu *l, const sim_fpu *r); INLINE_SIM_FPU (int) sim_fpu_is_gt (const sim_fpu *l, const sim_fpu *r); +/* Unordered/ordered comparison operators. */ + +INLINE_SIM_FPU (int) sim_fpu_un (int *is, const sim_fpu *l, const sim_fpu *r); +INLINE_SIM_FPU (int) sim_fpu_or (int *is, const sim_fpu *l, const sim_fpu *r); + +INLINE_SIM_FPU (int) sim_fpu_is_un (const sim_fpu *l, const sim_fpu *r); +INLINE_SIM_FPU (int) sim_fpu_is_or (const sim_fpu *l, const sim_fpu *r); + +/* Changes the behaviour of the library to IEEE754-2008 or IEEE754-1985. + The default for the library is IEEE754-1985. */ +INLINE_SIM_FPU (bool) sim_fpu_is_ieee754_1985 (void); +INLINE_SIM_FPU (bool) sim_fpu_is_ieee754_2008 (void); +INLINE_SIM_FPU (void) sim_fpu_set_mode (const sim_fpu_mode m); /* General number class and comparison operators. @@ -411,6 +434,7 @@ extern sim_fpu_state _sim_fpu; between pre-R6 and R6 MIPS cores. */ #define sim_fpu_quiet_nan_inverted _sim_fpu.quiet_nan_inverted +#define sim_fpu_current_mode _sim_fpu.current_mode /* A number of useful constants. */ -- 2.30.2