diff options
Diffstat (limited to 'fpu/softfloat.c')
| -rw-r--r-- | fpu/softfloat.c | 96 |
1 files changed, 83 insertions, 13 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index ee609540aa..f8f4ef51e8 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -500,14 +500,12 @@ static inline __attribute__((unused)) bool is_qnan(FloatClass c) } /* - * Structure holding all of the decomposed parts of a float. The - * exponent is unbiased and the fraction is normalized. All - * calculations are done with a 64 bit fraction and then rounded as - * appropriate for the final format. + * Structure holding all of the decomposed parts of a float. + * The exponent is unbiased and the fraction is normalized. * - * Thanks to the packed FloatClass a decent compiler should be able to - * fit the whole structure into registers and avoid using the stack - * for parameter passing. + * The fraction words are stored in big-endian word ordering, + * so that truncation from a larger format to a smaller format + * can be done simply by ignoring subsequent elements. */ typedef struct { @@ -527,6 +525,15 @@ typedef struct { }; } FloatParts64; +typedef struct { + FloatClass cls; + bool sign; + int32_t exp; + uint64_t frac_hi; + uint64_t frac_lo; +} FloatParts128; + +/* These apply to the most significant word of each FloatPartsN. */ #define DECOMPOSED_BINARY_POINT 63 #define DECOMPOSED_IMPLICIT_BIT (1ull << DECOMPOSED_BINARY_POINT) @@ -562,11 +569,11 @@ typedef struct { .exp_bias = ((1 << E) - 1) >> 1, \ .exp_max = (1 << E) - 1, \ .frac_size = F, \ - .frac_shift = DECOMPOSED_BINARY_POINT - F, \ - .frac_lsb = 1ull << (DECOMPOSED_BINARY_POINT - F), \ - .frac_lsbm1 = 1ull << ((DECOMPOSED_BINARY_POINT - F) - 1), \ - .round_mask = (1ull << (DECOMPOSED_BINARY_POINT - F)) - 1, \ - .roundeven_mask = (2ull << (DECOMPOSED_BINARY_POINT - F)) - 1 + .frac_shift = (-F - 1) & 63, \ + .frac_lsb = 1ull << ((-F - 1) & 63), \ + .frac_lsbm1 = 1ull << ((-F - 2) & 63), \ + .round_mask = (1ull << ((-F - 1) & 63)) - 1, \ + .roundeven_mask = (2ull << ((-F - 1) & 63)) - 1 static const FloatFmt float16_params = { FLOAT_PARAMS(5, 10) @@ -589,6 +596,10 @@ static const FloatFmt float64_params = { FLOAT_PARAMS(11, 52) }; +static const FloatFmt float128_params = { + FLOAT_PARAMS(15, 112) +}; + /* Unpack a float to parts, but do not canonicalize. */ static void unpack_raw64(FloatParts64 *r, const FloatFmt *fmt, uint64_t raw) { @@ -623,6 +634,20 @@ static inline void float64_unpack_raw(FloatParts64 *p, float64 f) unpack_raw64(p, &float64_params, f); } +static void float128_unpack_raw(FloatParts128 *p, float128 f) +{ + const int f_size = float128_params.frac_size - 64; + const int e_size = float128_params.exp_size; + + *p = (FloatParts128) { + .cls = float_class_unclassified, + .sign = extract64(f.high, f_size + e_size, 1), + .exp = extract64(f.high, f_size, e_size), + .frac_hi = extract64(f.high, 0, f_size), + .frac_lo = f.low, + }; +} + /* Pack a float from parts, but do not canonicalize. */ static uint64_t pack_raw64(const FloatParts64 *p, const FloatFmt *fmt) { @@ -656,6 +681,18 @@ static inline float64 float64_pack_raw(const FloatParts64 *p) return make_float64(pack_raw64(p, &float64_params)); } +static float128 float128_pack_raw(const FloatParts128 *p) +{ + const int f_size = float128_params.frac_size - 64; + const int e_size = float128_params.exp_size; + uint64_t hi; + + hi = (uint64_t)p->sign << (f_size + e_size); + hi = deposit64(hi, f_size, e_size, p->exp); + hi = deposit64(hi, 0, f_size, p->frac_hi); + return make_float128(hi, p->frac_lo); +} + /*---------------------------------------------------------------------------- | Functions and definitions to determine: (1) whether tininess for underflow | is detected before or after rounding by default, (2) what (if anything) @@ -666,8 +703,30 @@ static inline float64 float64_pack_raw(const FloatParts64 *p) *----------------------------------------------------------------------------*/ #include "softfloat-specialize.c.inc" +#define PARTS_GENERIC_64_128(NAME, P) \ + QEMU_GENERIC(P, (FloatParts128 *, parts128_##NAME), parts64_##NAME) + #define parts_default_nan parts64_default_nan -#define parts_silence_nan parts64_silence_nan +#define parts_silence_nan(P, S) PARTS_GENERIC_64_128(silence_nan, P)(P, S) + + +/* + * Helper functions for softfloat-parts.c.inc, per-size operations. + */ + +static void frac128_shl(FloatParts128 *a, int c) +{ + shift128Left(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo); +} + +#define frac_shl(A, C) frac128_shl(A, C) + +static void frac128_shr(FloatParts128 *a, int c) +{ + shift128Right(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo); +} + +#define frac_shr(A, C) frac128_shr(A, C) /* Canonicalize EXP and FRAC, setting CLS. */ static FloatParts64 sf_canonicalize(FloatParts64 part, const FloatFmt *parm, @@ -3851,6 +3910,17 @@ bfloat16 bfloat16_silence_nan(bfloat16 a, float_status *status) return bfloat16_pack_raw(&p); } +float128 float128_silence_nan(float128 a, float_status *status) +{ + FloatParts128 p; + + float128_unpack_raw(&p, a); + frac_shl(&p, float128_params.frac_shift); + parts_silence_nan(&p, status); + frac_shr(&p, float128_params.frac_shift); + return float128_pack_raw(&p); +} + /*---------------------------------------------------------------------------- | If `a' is denormal and we are in flush-to-zero mode then set the | input-denormal exception and return zero. Otherwise just return the value. |