@@ -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 {
@@ -526,6 +524,15 @@ 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)
@@ -561,11 +568,11 @@ 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)
@@ -588,6 +595,10 @@ 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)
{
@@ -622,6 +633,20 @@ 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)
{
@@ -655,6 +680,18 @@ 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)
@@ -665,8 +702,30 @@ 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,
@@ -3850,6 +3909,17 @@ 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.
@@ -198,6 +198,12 @@ static void parts64_silence_nan(FloatParts64 *p, float_status *status)
p->cls = float_class_qnan;
}
+static void parts128_silence_nan(FloatParts128 *p, float_status *status)
+{
+ p->frac_hi = parts_silence_nan_frac(p->frac_hi, status);
+ p->cls = float_class_qnan;
+}
+
/*----------------------------------------------------------------------------
| The pattern for a default generated extended double-precision NaN.
*----------------------------------------------------------------------------*/
@@ -1057,25 +1063,6 @@ bool float128_is_signaling_nan(float128 a, float_status *status)
}
}
-/*----------------------------------------------------------------------------
-| Returns a quiet NaN from a signalling NaN for the quadruple-precision
-| floating point value `a'.
-*----------------------------------------------------------------------------*/
-
-float128 float128_silence_nan(float128 a, float_status *status)
-{
- if (no_signaling_nans(status)) {
- g_assert_not_reached();
- } else {
- if (snan_bit_is_one(status)) {
- return float128_default_nan(status);
- } else {
- a.high |= UINT64_C(0x0000800000000000);
- return a;
- }
- }
-}
-
/*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point NaN
| `a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
This is the minimal change that also introduces float128_params, float128_unpack_raw, and float128_pack_raw without running into unused symbol Werrors. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- fpu/softfloat.c | 96 +++++++++++++++++++++++++++++----- fpu/softfloat-specialize.c.inc | 25 +++------ 2 files changed, 89 insertions(+), 32 deletions(-)