softfloat: Move round_canonical to softfloat-parts.c.inc
At the same time, convert to pointers, renaming to parts$N_uncanon, and define a macro for parts_uncanon using QEMU_GENERIC. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson
parent
d46975bce1
commit
ee6959f277
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@ -133,3 +133,151 @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
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? float_class_snan : float_class_qnan);
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}
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}
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/*
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* Round and uncanonicalize a floating-point number by parts. There
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* are FRAC_SHIFT bits that may require rounding at the bottom of the
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* fraction; these bits will be removed. The exponent will be biased
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* by EXP_BIAS and must be bounded by [EXP_MAX-1, 0].
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*/
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static void partsN(uncanon)(FloatPartsN *p, float_status *s,
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const FloatFmt *fmt)
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{
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const int exp_max = fmt->exp_max;
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const int frac_shift = fmt->frac_shift;
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const uint64_t frac_lsb = fmt->frac_lsb;
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const uint64_t frac_lsbm1 = fmt->frac_lsbm1;
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const uint64_t round_mask = fmt->round_mask;
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const uint64_t roundeven_mask = fmt->roundeven_mask;
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uint64_t inc;
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bool overflow_norm;
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int exp, flags = 0;
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if (unlikely(p->cls != float_class_normal)) {
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switch (p->cls) {
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case float_class_zero:
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p->exp = 0;
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frac_clear(p);
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return;
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case float_class_inf:
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g_assert(!fmt->arm_althp);
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p->exp = fmt->exp_max;
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frac_clear(p);
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return;
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case float_class_qnan:
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case float_class_snan:
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g_assert(!fmt->arm_althp);
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p->exp = fmt->exp_max;
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frac_shr(p, fmt->frac_shift);
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return;
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default:
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break;
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}
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g_assert_not_reached();
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}
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switch (s->float_rounding_mode) {
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case float_round_nearest_even:
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overflow_norm = false;
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inc = ((p->frac_lo & roundeven_mask) != frac_lsbm1 ? frac_lsbm1 : 0);
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break;
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case float_round_ties_away:
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overflow_norm = false;
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inc = frac_lsbm1;
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break;
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case float_round_to_zero:
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overflow_norm = true;
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inc = 0;
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break;
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case float_round_up:
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inc = p->sign ? 0 : round_mask;
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overflow_norm = p->sign;
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break;
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case float_round_down:
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inc = p->sign ? round_mask : 0;
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overflow_norm = !p->sign;
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break;
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case float_round_to_odd:
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overflow_norm = true;
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inc = p->frac_lo & frac_lsb ? 0 : round_mask;
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break;
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default:
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g_assert_not_reached();
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}
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exp = p->exp + fmt->exp_bias;
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if (likely(exp > 0)) {
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if (p->frac_lo & round_mask) {
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flags |= float_flag_inexact;
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if (frac_addi(p, p, inc)) {
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frac_shr(p, 1);
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p->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
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exp++;
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}
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}
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frac_shr(p, frac_shift);
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if (fmt->arm_althp) {
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/* ARM Alt HP eschews Inf and NaN for a wider exponent. */
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if (unlikely(exp > exp_max)) {
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/* Overflow. Return the maximum normal. */
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flags = float_flag_invalid;
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exp = exp_max;
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frac_allones(p);
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}
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} else if (unlikely(exp >= exp_max)) {
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flags |= float_flag_overflow | float_flag_inexact;
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if (overflow_norm) {
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exp = exp_max - 1;
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frac_allones(p);
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} else {
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p->cls = float_class_inf;
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exp = exp_max;
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frac_clear(p);
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}
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}
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} else if (s->flush_to_zero) {
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flags |= float_flag_output_denormal;
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p->cls = float_class_zero;
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exp = 0;
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frac_clear(p);
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} else {
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bool is_tiny = s->tininess_before_rounding || exp < 0;
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if (!is_tiny) {
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FloatPartsN discard;
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is_tiny = !frac_addi(&discard, p, inc);
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}
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frac_shrjam(p, 1 - exp);
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if (p->frac_lo & round_mask) {
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/* Need to recompute round-to-even/round-to-odd. */
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switch (s->float_rounding_mode) {
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case float_round_nearest_even:
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inc = ((p->frac_lo & roundeven_mask) != frac_lsbm1
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? frac_lsbm1 : 0);
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break;
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case float_round_to_odd:
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inc = p->frac_lo & frac_lsb ? 0 : round_mask;
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break;
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default:
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break;
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}
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flags |= float_flag_inexact;
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frac_addi(p, p, inc);
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}
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exp = (p->frac_hi & DECOMPOSED_IMPLICIT_BIT) != 0;
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frac_shr(p, frac_shift);
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if (is_tiny && (flags & float_flag_inexact)) {
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flags |= float_flag_underflow;
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}
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if (exp == 0 && frac_eqz(p)) {
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p->cls = float_class_zero;
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}
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}
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p->exp = exp;
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float_raise(flags, s);
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}
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201
fpu/softfloat.c
201
fpu/softfloat.c
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@ -741,6 +741,14 @@ static void parts128_canonicalize(FloatParts128 *p, float_status *status,
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#define parts_canonicalize(A, S, F) \
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PARTS_GENERIC_64_128(canonicalize, A)(A, S, F)
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static void parts64_uncanon(FloatParts64 *p, float_status *status,
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const FloatFmt *fmt);
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static void parts128_uncanon(FloatParts128 *p, float_status *status,
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const FloatFmt *fmt);
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#define parts_uncanon(A, S, F) \
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PARTS_GENERIC_64_128(uncanon, A)(A, S, F)
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/*
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* Helper functions for softfloat-parts.c.inc, per-size operations.
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*/
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@ -748,6 +756,31 @@ static void parts128_canonicalize(FloatParts128 *p, float_status *status,
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#define FRAC_GENERIC_64_128(NAME, P) \
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QEMU_GENERIC(P, (FloatParts128 *, frac128_##NAME), frac64_##NAME)
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static bool frac64_addi(FloatParts64 *r, FloatParts64 *a, uint64_t c)
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{
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return uadd64_overflow(a->frac, c, &r->frac);
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}
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static bool frac128_addi(FloatParts128 *r, FloatParts128 *a, uint64_t c)
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{
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c = uadd64_overflow(a->frac_lo, c, &r->frac_lo);
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return uadd64_overflow(a->frac_hi, c, &r->frac_hi);
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}
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#define frac_addi(R, A, C) FRAC_GENERIC_64_128(addi, R)(R, A, C)
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static void frac64_allones(FloatParts64 *a)
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{
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a->frac = -1;
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}
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static void frac128_allones(FloatParts128 *a)
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{
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a->frac_hi = a->frac_lo = -1;
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}
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#define frac_allones(A) FRAC_GENERIC_64_128(allones, A)(A)
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static int frac64_cmp(FloatParts64 *a, FloatParts64 *b)
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{
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return a->frac == b->frac ? 0 : a->frac < b->frac ? -1 : 1;
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@ -846,161 +879,17 @@ static void frac128_shr(FloatParts128 *a, int c)
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#define frac_shr(A, C) FRAC_GENERIC_64_128(shr, A)(A, C)
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/* Round and uncanonicalize a floating-point number by parts. There
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* are FRAC_SHIFT bits that may require rounding at the bottom of the
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* fraction; these bits will be removed. The exponent will be biased
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* by EXP_BIAS and must be bounded by [EXP_MAX-1, 0].
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*/
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static FloatParts64 round_canonical(FloatParts64 p, float_status *s,
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const FloatFmt *parm)
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static void frac64_shrjam(FloatParts64 *a, int c)
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{
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const uint64_t frac_lsb = parm->frac_lsb;
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const uint64_t frac_lsbm1 = parm->frac_lsbm1;
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const uint64_t round_mask = parm->round_mask;
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const uint64_t roundeven_mask = parm->roundeven_mask;
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const int exp_max = parm->exp_max;
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const int frac_shift = parm->frac_shift;
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uint64_t frac, inc;
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int exp, flags = 0;
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bool overflow_norm;
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frac = p.frac;
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exp = p.exp;
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switch (p.cls) {
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case float_class_normal:
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switch (s->float_rounding_mode) {
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case float_round_nearest_even:
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overflow_norm = false;
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inc = ((frac & roundeven_mask) != frac_lsbm1 ? frac_lsbm1 : 0);
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break;
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case float_round_ties_away:
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overflow_norm = false;
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inc = frac_lsbm1;
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break;
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case float_round_to_zero:
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overflow_norm = true;
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inc = 0;
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break;
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case float_round_up:
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inc = p.sign ? 0 : round_mask;
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overflow_norm = p.sign;
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break;
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case float_round_down:
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inc = p.sign ? round_mask : 0;
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overflow_norm = !p.sign;
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break;
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case float_round_to_odd:
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overflow_norm = true;
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inc = frac & frac_lsb ? 0 : round_mask;
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break;
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default:
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g_assert_not_reached();
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}
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exp += parm->exp_bias;
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if (likely(exp > 0)) {
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if (frac & round_mask) {
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flags |= float_flag_inexact;
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if (uadd64_overflow(frac, inc, &frac)) {
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frac = (frac >> 1) | DECOMPOSED_IMPLICIT_BIT;
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exp++;
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}
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}
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frac >>= frac_shift;
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if (parm->arm_althp) {
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/* ARM Alt HP eschews Inf and NaN for a wider exponent. */
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if (unlikely(exp > exp_max)) {
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/* Overflow. Return the maximum normal. */
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flags = float_flag_invalid;
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exp = exp_max;
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frac = -1;
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}
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} else if (unlikely(exp >= exp_max)) {
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flags |= float_flag_overflow | float_flag_inexact;
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if (overflow_norm) {
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exp = exp_max - 1;
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frac = -1;
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} else {
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p.cls = float_class_inf;
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goto do_inf;
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}
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}
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} else if (s->flush_to_zero) {
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flags |= float_flag_output_denormal;
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p.cls = float_class_zero;
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goto do_zero;
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} else {
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bool is_tiny = s->tininess_before_rounding || (exp < 0);
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if (!is_tiny) {
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uint64_t discard;
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is_tiny = !uadd64_overflow(frac, inc, &discard);
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}
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shift64RightJamming(frac, 1 - exp, &frac);
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if (frac & round_mask) {
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/* Need to recompute round-to-even. */
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switch (s->float_rounding_mode) {
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case float_round_nearest_even:
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inc = ((frac & roundeven_mask) != frac_lsbm1
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? frac_lsbm1 : 0);
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break;
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case float_round_to_odd:
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inc = frac & frac_lsb ? 0 : round_mask;
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break;
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default:
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break;
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}
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flags |= float_flag_inexact;
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frac += inc;
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}
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exp = (frac & DECOMPOSED_IMPLICIT_BIT ? 1 : 0);
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frac >>= frac_shift;
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if (is_tiny && (flags & float_flag_inexact)) {
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flags |= float_flag_underflow;
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}
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if (exp == 0 && frac == 0) {
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p.cls = float_class_zero;
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}
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}
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break;
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case float_class_zero:
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do_zero:
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exp = 0;
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frac = 0;
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break;
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case float_class_inf:
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do_inf:
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assert(!parm->arm_althp);
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exp = exp_max;
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frac = 0;
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break;
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case float_class_qnan:
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case float_class_snan:
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assert(!parm->arm_althp);
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exp = exp_max;
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frac >>= parm->frac_shift;
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break;
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default:
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g_assert_not_reached();
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}
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float_raise(flags, s);
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p.exp = exp;
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p.frac = frac;
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return p;
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shift64RightJamming(a->frac, c, &a->frac);
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}
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static void frac128_shrjam(FloatParts128 *a, int c)
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{
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shift128RightJamming(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo);
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}
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#define frac_shrjam(A, C) FRAC_GENERIC_64_128(shrjam, A)(A, C)
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#define partsN(NAME) parts64_##NAME
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#define FloatPartsN FloatParts64
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@ -1045,7 +934,7 @@ static float16 float16a_round_pack_canonical(FloatParts64 *p,
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float_status *s,
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const FloatFmt *params)
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{
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*p = round_canonical(*p, s, params);
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parts_uncanon(p, s, params);
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return float16_pack_raw(p);
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}
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@ -1058,7 +947,7 @@ static float16 float16_round_pack_canonical(FloatParts64 *p,
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static bfloat16 bfloat16_round_pack_canonical(FloatParts64 *p,
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float_status *s)
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{
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*p = round_canonical(*p, s, &bfloat16_params);
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parts_uncanon(p, s, &bfloat16_params);
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return bfloat16_pack_raw(p);
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}
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@ -1072,7 +961,7 @@ static void float32_unpack_canonical(FloatParts64 *p, float32 f,
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static float32 float32_round_pack_canonical(FloatParts64 *p,
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float_status *s)
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{
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*p = round_canonical(*p, s, &float32_params);
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parts_uncanon(p, s, &float32_params);
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return float32_pack_raw(p);
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}
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@ -1086,7 +975,7 @@ static void float64_unpack_canonical(FloatParts64 *p, float64 f,
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static float64 float64_round_pack_canonical(FloatParts64 *p,
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float_status *s)
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{
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*p = round_canonical(*p, s, &float64_params);
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parts_uncanon(p, s, &float64_params);
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return float64_pack_raw(p);
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}
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