@@ -741,6 +741,14 @@ static void parts128_canonicalize(FloatParts128 *p, float_status *status,
#define parts_canonicalize(A, S, F) \
PARTS_GENERIC_64_128(canonicalize, A)(A, S, F)
+static void parts64_uncanon(FloatParts64 *p, float_status *status,
+ const FloatFmt *fmt);
+static void parts128_uncanon(FloatParts128 *p, float_status *status,
+ const FloatFmt *fmt);
+
+#define parts_uncanon(A, S, F) \
+ PARTS_GENERIC_64_128(uncanon, A)(A, S, F)
+
/*
* Helper functions for softfloat-parts.c.inc, per-size operations.
*/
@@ -748,6 +756,31 @@ static void parts128_canonicalize(FloatParts128 *p, float_status *status,
#define FRAC_GENERIC_64_128(NAME, P) \
QEMU_GENERIC(P, (FloatParts128 *, frac128_##NAME), frac64_##NAME)
+static bool frac64_addi(FloatParts64 *r, FloatParts64 *a, uint64_t c)
+{
+ return uadd64_overflow(a->frac, c, &r->frac);
+}
+
+static bool frac128_addi(FloatParts128 *r, FloatParts128 *a, uint64_t c)
+{
+ c = uadd64_overflow(a->frac_lo, c, &r->frac_lo);
+ return uadd64_overflow(a->frac_hi, c, &r->frac_hi);
+}
+
+#define frac_addi(R, A, C) FRAC_GENERIC_64_128(addi, R)(R, A, C)
+
+static void frac64_allones(FloatParts64 *a)
+{
+ a->frac = -1;
+}
+
+static void frac128_allones(FloatParts128 *a)
+{
+ a->frac_hi = a->frac_lo = -1;
+}
+
+#define frac_allones(A) FRAC_GENERIC_64_128(allones, A)(A)
+
static int frac64_cmp(FloatParts64 *a, FloatParts64 *b)
{
return a->frac == b->frac ? 0 : a->frac < b->frac ? -1 : 1;
@@ -846,161 +879,17 @@ static void frac128_shr(FloatParts128 *a, int c)
#define frac_shr(A, C) FRAC_GENERIC_64_128(shr, A)(A, C)
-
-/* Round and uncanonicalize a floating-point number by parts. There
- * are FRAC_SHIFT bits that may require rounding at the bottom of the
- * fraction; these bits will be removed. The exponent will be biased
- * by EXP_BIAS and must be bounded by [EXP_MAX-1, 0].
- */
-
-static FloatParts64 round_canonical(FloatParts64 p, float_status *s,
- const FloatFmt *parm)
+static void frac64_shrjam(FloatParts64 *a, int c)
{
- const uint64_t frac_lsb = parm->frac_lsb;
- const uint64_t frac_lsbm1 = parm->frac_lsbm1;
- const uint64_t round_mask = parm->round_mask;
- const uint64_t roundeven_mask = parm->roundeven_mask;
- const int exp_max = parm->exp_max;
- const int frac_shift = parm->frac_shift;
- uint64_t frac, inc;
- int exp, flags = 0;
- bool overflow_norm;
-
- frac = p.frac;
- exp = p.exp;
-
- switch (p.cls) {
- case float_class_normal:
- switch (s->float_rounding_mode) {
- case float_round_nearest_even:
- overflow_norm = false;
- inc = ((frac & roundeven_mask) != frac_lsbm1 ? frac_lsbm1 : 0);
- break;
- case float_round_ties_away:
- overflow_norm = false;
- inc = frac_lsbm1;
- break;
- case float_round_to_zero:
- overflow_norm = true;
- inc = 0;
- break;
- case float_round_up:
- inc = p.sign ? 0 : round_mask;
- overflow_norm = p.sign;
- break;
- case float_round_down:
- inc = p.sign ? round_mask : 0;
- overflow_norm = !p.sign;
- break;
- case float_round_to_odd:
- overflow_norm = true;
- inc = frac & frac_lsb ? 0 : round_mask;
- break;
- default:
- g_assert_not_reached();
- }
-
- exp += parm->exp_bias;
- if (likely(exp > 0)) {
- if (frac & round_mask) {
- flags |= float_flag_inexact;
- if (uadd64_overflow(frac, inc, &frac)) {
- frac = (frac >> 1) | DECOMPOSED_IMPLICIT_BIT;
- exp++;
- }
- }
- frac >>= frac_shift;
-
- if (parm->arm_althp) {
- /* ARM Alt HP eschews Inf and NaN for a wider exponent. */
- if (unlikely(exp > exp_max)) {
- /* Overflow. Return the maximum normal. */
- flags = float_flag_invalid;
- exp = exp_max;
- frac = -1;
- }
- } else if (unlikely(exp >= exp_max)) {
- flags |= float_flag_overflow | float_flag_inexact;
- if (overflow_norm) {
- exp = exp_max - 1;
- frac = -1;
- } else {
- p.cls = float_class_inf;
- goto do_inf;
- }
- }
- } else if (s->flush_to_zero) {
- flags |= float_flag_output_denormal;
- p.cls = float_class_zero;
- goto do_zero;
- } else {
- bool is_tiny = s->tininess_before_rounding || (exp < 0);
-
- if (!is_tiny) {
- uint64_t discard;
- is_tiny = !uadd64_overflow(frac, inc, &discard);
- }
-
- shift64RightJamming(frac, 1 - exp, &frac);
- if (frac & round_mask) {
- /* Need to recompute round-to-even. */
- switch (s->float_rounding_mode) {
- case float_round_nearest_even:
- inc = ((frac & roundeven_mask) != frac_lsbm1
- ? frac_lsbm1 : 0);
- break;
- case float_round_to_odd:
- inc = frac & frac_lsb ? 0 : round_mask;
- break;
- default:
- break;
- }
- flags |= float_flag_inexact;
- frac += inc;
- }
-
- exp = (frac & DECOMPOSED_IMPLICIT_BIT ? 1 : 0);
- frac >>= frac_shift;
-
- if (is_tiny && (flags & float_flag_inexact)) {
- flags |= float_flag_underflow;
- }
- if (exp == 0 && frac == 0) {
- p.cls = float_class_zero;
- }
- }
- break;
-
- case float_class_zero:
- do_zero:
- exp = 0;
- frac = 0;
- break;
-
- case float_class_inf:
- do_inf:
- assert(!parm->arm_althp);
- exp = exp_max;
- frac = 0;
- break;
-
- case float_class_qnan:
- case float_class_snan:
- assert(!parm->arm_althp);
- exp = exp_max;
- frac >>= parm->frac_shift;
- break;
-
- default:
- g_assert_not_reached();
- }
-
- float_raise(flags, s);
- p.exp = exp;
- p.frac = frac;
- return p;
+ shift64RightJamming(a->frac, c, &a->frac);
}
+static void frac128_shrjam(FloatParts128 *a, int c)
+{
+ shift128RightJamming(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo);
+}
+
+#define frac_shrjam(A, C) FRAC_GENERIC_64_128(shrjam, A)(A, C)
#define partsN(NAME) parts64_##NAME
#define FloatPartsN FloatParts64
@@ -1045,7 +934,7 @@ static float16 float16a_round_pack_canonical(FloatParts64 *p,
float_status *s,
const FloatFmt *params)
{
- *p = round_canonical(*p, s, params);
+ parts_uncanon(p, s, params);
return float16_pack_raw(p);
}
@@ -1058,7 +947,7 @@ static float16 float16_round_pack_canonical(FloatParts64 *p,
static bfloat16 bfloat16_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- *p = round_canonical(*p, s, &bfloat16_params);
+ parts_uncanon(p, s, &bfloat16_params);
return bfloat16_pack_raw(p);
}
@@ -1072,7 +961,7 @@ static void float32_unpack_canonical(FloatParts64 *p, float32 f,
static float32 float32_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- *p = round_canonical(*p, s, &float32_params);
+ parts_uncanon(p, s, &float32_params);
return float32_pack_raw(p);
}
@@ -1086,7 +975,7 @@ static void float64_unpack_canonical(FloatParts64 *p, float64 f,
static float64 float64_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- *p = round_canonical(*p, s, &float64_params);
+ parts_uncanon(p, s, &float64_params);
return float64_pack_raw(p);
}
@@ -133,3 +133,151 @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
? float_class_snan : float_class_qnan);
}
}
+
+/*
+ * Round and uncanonicalize a floating-point number by parts. There
+ * are FRAC_SHIFT bits that may require rounding at the bottom of the
+ * fraction; these bits will be removed. The exponent will be biased
+ * by EXP_BIAS and must be bounded by [EXP_MAX-1, 0].
+ */
+static void partsN(uncanon)(FloatPartsN *p, float_status *s,
+ const FloatFmt *fmt)
+{
+ const int exp_max = fmt->exp_max;
+ const int frac_shift = fmt->frac_shift;
+ const uint64_t frac_lsb = fmt->frac_lsb;
+ const uint64_t frac_lsbm1 = fmt->frac_lsbm1;
+ const uint64_t round_mask = fmt->round_mask;
+ const uint64_t roundeven_mask = fmt->roundeven_mask;
+ uint64_t inc;
+ bool overflow_norm;
+ int exp, flags = 0;
+
+ if (unlikely(p->cls != float_class_normal)) {
+ switch (p->cls) {
+ case float_class_zero:
+ p->exp = 0;
+ frac_clear(p);
+ return;
+ case float_class_inf:
+ g_assert(!fmt->arm_althp);
+ p->exp = fmt->exp_max;
+ frac_clear(p);
+ return;
+ case float_class_qnan:
+ case float_class_snan:
+ g_assert(!fmt->arm_althp);
+ p->exp = fmt->exp_max;
+ frac_shr(p, fmt->frac_shift);
+ return;
+ default:
+ break;
+ }
+ g_assert_not_reached();
+ }
+
+ switch (s->float_rounding_mode) {
+ case float_round_nearest_even:
+ overflow_norm = false;
+ inc = ((p->frac_lo & roundeven_mask) != frac_lsbm1 ? frac_lsbm1 : 0);
+ break;
+ case float_round_ties_away:
+ overflow_norm = false;
+ inc = frac_lsbm1;
+ break;
+ case float_round_to_zero:
+ overflow_norm = true;
+ inc = 0;
+ break;
+ case float_round_up:
+ inc = p->sign ? 0 : round_mask;
+ overflow_norm = p->sign;
+ break;
+ case float_round_down:
+ inc = p->sign ? round_mask : 0;
+ overflow_norm = !p->sign;
+ break;
+ case float_round_to_odd:
+ overflow_norm = true;
+ inc = p->frac_lo & frac_lsb ? 0 : round_mask;
+ break;
+ default:
+ g_assert_not_reached();
+ }
+
+ exp = p->exp + fmt->exp_bias;
+ if (likely(exp > 0)) {
+ if (p->frac_lo & round_mask) {
+ flags |= float_flag_inexact;
+ if (frac_addi(p, p, inc)) {
+ frac_shr(p, 1);
+ p->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
+ exp++;
+ }
+ }
+ frac_shr(p, frac_shift);
+
+ if (fmt->arm_althp) {
+ /* ARM Alt HP eschews Inf and NaN for a wider exponent. */
+ if (unlikely(exp > exp_max)) {
+ /* Overflow. Return the maximum normal. */
+ flags = float_flag_invalid;
+ exp = exp_max;
+ frac_allones(p);
+ }
+ } else if (unlikely(exp >= exp_max)) {
+ flags |= float_flag_overflow | float_flag_inexact;
+ if (overflow_norm) {
+ exp = exp_max - 1;
+ frac_allones(p);
+ } else {
+ p->cls = float_class_inf;
+ exp = exp_max;
+ frac_clear(p);
+ }
+ }
+ } else if (s->flush_to_zero) {
+ flags |= float_flag_output_denormal;
+ p->cls = float_class_zero;
+ exp = 0;
+ frac_clear(p);
+ } else {
+ bool is_tiny = s->tininess_before_rounding || exp < 0;
+
+ if (!is_tiny) {
+ FloatPartsN discard;
+ is_tiny = !frac_addi(&discard, p, inc);
+ }
+
+ frac_shrjam(p, 1 - exp);
+
+ if (p->frac_lo & round_mask) {
+ /* Need to recompute round-to-even/round-to-odd. */
+ switch (s->float_rounding_mode) {
+ case float_round_nearest_even:
+ inc = ((p->frac_lo & roundeven_mask) != frac_lsbm1
+ ? frac_lsbm1 : 0);
+ break;
+ case float_round_to_odd:
+ inc = p->frac_lo & frac_lsb ? 0 : round_mask;
+ break;
+ default:
+ break;
+ }
+ flags |= float_flag_inexact;
+ frac_addi(p, p, inc);
+ }
+
+ exp = (p->frac_hi & DECOMPOSED_IMPLICIT_BIT) != 0;
+ frac_shr(p, frac_shift);
+
+ if (is_tiny && (flags & float_flag_inexact)) {
+ flags |= float_flag_underflow;
+ }
+ if (exp == 0 && frac_eqz(p)) {
+ p->cls = float_class_zero;
+ }
+ }
+ p->exp = exp;
+ float_raise(flags, s);
+}