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-rw-r--r--fpu/softfloat-parts.c.inc55
-rw-r--r--fpu/softfloat.c290
2 files changed, 171 insertions, 174 deletions
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index a203811..f8165d9 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -539,3 +539,58 @@ static FloatPartsN *partsN(muladd)(FloatPartsN *a, FloatPartsN *b,
parts_default_nan(a, s);
return a;
}
+
+/*
+ * Returns the result of dividing the floating-point value `a' by the
+ * corresponding value `b'. The operation is performed according to
+ * the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
+ */
+static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
+ float_status *s)
+{
+ int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
+ bool sign = a->sign ^ b->sign;
+
+ if (likely(ab_mask == float_cmask_normal)) {
+ a->sign = sign;
+ a->exp -= b->exp + frac_div(a, b);
+ return a;
+ }
+
+ /* 0/0 or Inf/Inf => NaN */
+ if (unlikely(ab_mask == float_cmask_zero) ||
+ unlikely(ab_mask == float_cmask_inf)) {
+ float_raise(float_flag_invalid, s);
+ parts_default_nan(a, s);
+ return a;
+ }
+
+ /* All the NaN cases */
+ if (unlikely(ab_mask & float_cmask_anynan)) {
+ return parts_pick_nan(a, b, s);
+ }
+
+ a->sign = sign;
+
+ /* Inf / X */
+ if (a->cls == float_class_inf) {
+ return a;
+ }
+
+ /* 0 / X */
+ if (a->cls == float_class_zero) {
+ return a;
+ }
+
+ /* X / Inf */
+ if (b->cls == float_class_inf) {
+ a->cls = float_class_zero;
+ return a;
+ }
+
+ /* X / 0 => Inf */
+ g_assert(b->cls == float_class_zero);
+ float_raise(float_flag_divbyzero, s);
+ a->cls = float_class_inf;
+ return a;
+}
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 3468995..a6dbb1d 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -803,6 +803,14 @@ static FloatParts128 *parts128_muladd(FloatParts128 *a, FloatParts128 *b,
#define parts_muladd(A, B, C, Z, S) \
PARTS_GENERIC_64_128(muladd, A)(A, B, C, Z, S)
+static FloatParts64 *parts64_div(FloatParts64 *a, FloatParts64 *b,
+ float_status *s);
+static FloatParts128 *parts128_div(FloatParts128 *a, FloatParts128 *b,
+ float_status *s);
+
+#define parts_div(A, B, S) \
+ PARTS_GENERIC_64_128(div, A)(A, B, S)
+
/*
* Helper functions for softfloat-parts.c.inc, per-size operations.
*/
@@ -895,6 +903,87 @@ static void frac128_clear(FloatParts128 *a)
#define frac_clear(A) FRAC_GENERIC_64_128(clear, A)(A)
+static bool frac64_div(FloatParts64 *a, FloatParts64 *b)
+{
+ uint64_t n1, n0, r, q;
+ bool ret;
+
+ /*
+ * We want a 2*N / N-bit division to produce exactly an N-bit
+ * result, so that we do not lose any precision and so that we
+ * do not have to renormalize afterward. If A.frac < B.frac,
+ * then division would produce an (N-1)-bit result; shift A left
+ * by one to produce the an N-bit result, and return true to
+ * decrement the exponent to match.
+ *
+ * The udiv_qrnnd algorithm that we're using requires normalization,
+ * i.e. the msb of the denominator must be set, which is already true.
+ */
+ ret = a->frac < b->frac;
+ if (ret) {
+ n0 = a->frac;
+ n1 = 0;
+ } else {
+ n0 = a->frac >> 1;
+ n1 = a->frac << 63;
+ }
+ q = udiv_qrnnd(&r, n0, n1, b->frac);
+
+ /* Set lsb if there is a remainder, to set inexact. */
+ a->frac = q | (r != 0);
+
+ return ret;
+}
+
+static bool frac128_div(FloatParts128 *a, FloatParts128 *b)
+{
+ uint64_t q0, q1, a0, a1, b0, b1;
+ uint64_t r0, r1, r2, r3, t0, t1, t2, t3;
+ bool ret = false;
+
+ a0 = a->frac_hi, a1 = a->frac_lo;
+ b0 = b->frac_hi, b1 = b->frac_lo;
+
+ ret = lt128(a0, a1, b0, b1);
+ if (!ret) {
+ a1 = shr_double(a0, a1, 1);
+ a0 = a0 >> 1;
+ }
+
+ /* Use 128/64 -> 64 division as estimate for 192/128 -> 128 division. */
+ q0 = estimateDiv128To64(a0, a1, b0);
+
+ /*
+ * Estimate is high because B1 was not included (unless B1 == 0).
+ * Reduce quotient and increase remainder until remainder is non-negative.
+ * This loop will execute 0 to 2 times.
+ */
+ mul128By64To192(b0, b1, q0, &t0, &t1, &t2);
+ sub192(a0, a1, 0, t0, t1, t2, &r0, &r1, &r2);
+ while (r0 != 0) {
+ q0--;
+ add192(r0, r1, r2, 0, b0, b1, &r0, &r1, &r2);
+ }
+
+ /* Repeat using the remainder, producing a second word of quotient. */
+ q1 = estimateDiv128To64(r1, r2, b0);
+ mul128By64To192(b0, b1, q1, &t1, &t2, &t3);
+ sub192(r1, r2, 0, t1, t2, t3, &r1, &r2, &r3);
+ while (r1 != 0) {
+ q1--;
+ add192(r1, r2, r3, 0, b0, b1, &r1, &r2, &r3);
+ }
+
+ /* Any remainder indicates inexact; set sticky bit. */
+ q1 |= (r2 | r3) != 0;
+
+ a->frac_hi = q0;
+ a->frac_lo = q1;
+ return ret;
+}
+
+#define frac_div(A, B) FRAC_GENERIC_64_128(div, A)(A, B)
+
static bool frac64_eqz(FloatParts64 *a)
{
return a->frac == 0;
@@ -1821,110 +1910,42 @@ float128 QEMU_FLATTEN float128_muladd(float128 a, float128 b, float128 c,
}
/*
- * Returns the result of dividing the floating-point value `a' by the
- * corresponding value `b'. The operation is performed according to
- * the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
+ * Division
*/
-static FloatParts64 div_floats(FloatParts64 a, FloatParts64 b, float_status *s)
-{
- bool sign = a.sign ^ b.sign;
-
- if (a.cls == float_class_normal && b.cls == float_class_normal) {
- uint64_t n0, n1, q, r;
- int exp = a.exp - b.exp;
-
- /*
- * We want a 2*N / N-bit division to produce exactly an N-bit
- * result, so that we do not lose any precision and so that we
- * do not have to renormalize afterward. If A.frac < B.frac,
- * then division would produce an (N-1)-bit result; shift A left
- * by one to produce the an N-bit result, and decrement the
- * exponent to match.
- *
- * The udiv_qrnnd algorithm that we're using requires normalization,
- * i.e. the msb of the denominator must be set, which is already true.
- */
- if (a.frac < b.frac) {
- exp -= 1;
- shift128Left(0, a.frac, DECOMPOSED_BINARY_POINT + 1, &n1, &n0);
- } else {
- shift128Left(0, a.frac, DECOMPOSED_BINARY_POINT, &n1, &n0);
- }
- q = udiv_qrnnd(&r, n1, n0, b.frac);
-
- /* Set lsb if there is a remainder, to set inexact. */
- a.frac = q | (r != 0);
- a.sign = sign;
- a.exp = exp;
- return a;
- }
- /* handle all the NaN cases */
- if (is_nan(a.cls) || is_nan(b.cls)) {
- return *parts_pick_nan(&a, &b, s);
- }
- /* 0/0 or Inf/Inf */
- if (a.cls == b.cls
- &&
- (a.cls == float_class_inf || a.cls == float_class_zero)) {
- float_raise(float_flag_invalid, s);
- parts_default_nan(&a, s);
- return a;
- }
- /* Inf / x or 0 / x */
- if (a.cls == float_class_inf || a.cls == float_class_zero) {
- a.sign = sign;
- return a;
- }
- /* Div 0 => Inf */
- if (b.cls == float_class_zero) {
- float_raise(float_flag_divbyzero, s);
- a.cls = float_class_inf;
- a.sign = sign;
- return a;
- }
- /* Div by Inf */
- if (b.cls == float_class_inf) {
- a.cls = float_class_zero;
- a.sign = sign;
- return a;
- }
- g_assert_not_reached();
-}
-
float16 float16_div(float16 a, float16 b, float_status *status)
{
- FloatParts64 pa, pb, pr;
+ FloatParts64 pa, pb, *pr;
float16_unpack_canonical(&pa, a, status);
float16_unpack_canonical(&pb, b, status);
- pr = div_floats(pa, pb, status);
+ pr = parts_div(&pa, &pb, status);
- return float16_round_pack_canonical(&pr, status);
+ return float16_round_pack_canonical(pr, status);
}
static float32 QEMU_SOFTFLOAT_ATTR
soft_f32_div(float32 a, float32 b, float_status *status)
{
- FloatParts64 pa, pb, pr;
+ FloatParts64 pa, pb, *pr;
float32_unpack_canonical(&pa, a, status);
float32_unpack_canonical(&pb, b, status);
- pr = div_floats(pa, pb, status);
+ pr = parts_div(&pa, &pb, status);
- return float32_round_pack_canonical(&pr, status);
+ return float32_round_pack_canonical(pr, status);
}
static float64 QEMU_SOFTFLOAT_ATTR
soft_f64_div(float64 a, float64 b, float_status *status)
{
- FloatParts64 pa, pb, pr;
+ FloatParts64 pa, pb, *pr;
float64_unpack_canonical(&pa, a, status);
float64_unpack_canonical(&pb, b, status);
- pr = div_floats(pa, pb, status);
+ pr = parts_div(&pa, &pb, status);
- return float64_round_pack_canonical(&pr, status);
+ return float64_round_pack_canonical(pr, status);
}
static float hard_f32_div(float a, float b)
@@ -1985,20 +2006,28 @@ float64_div(float64 a, float64 b, float_status *s)
f64_div_pre, f64_div_post);
}
-/*
- * Returns the result of dividing the bfloat16
- * value `a' by the corresponding value `b'.
- */
-
-bfloat16 bfloat16_div(bfloat16 a, bfloat16 b, float_status *status)
+bfloat16 QEMU_FLATTEN
+bfloat16_div(bfloat16 a, bfloat16 b, float_status *status)
{
- FloatParts64 pa, pb, pr;
+ FloatParts64 pa, pb, *pr;
bfloat16_unpack_canonical(&pa, a, status);
bfloat16_unpack_canonical(&pb, b, status);
- pr = div_floats(pa, pb, status);
+ pr = parts_div(&pa, &pb, status);
- return bfloat16_round_pack_canonical(&pr, status);
+ return bfloat16_round_pack_canonical(pr, status);
+}
+
+float128 QEMU_FLATTEN
+float128_div(float128 a, float128 b, float_status *status)
+{
+ FloatParts128 pa, pb, *pr;
+
+ float128_unpack_canonical(&pa, a, status);
+ float128_unpack_canonical(&pb, b, status);
+ pr = parts_div(&pa, &pb, status);
+
+ return float128_round_pack_canonical(pr, status);
}
/*
@@ -7124,93 +7153,6 @@ float128 float128_round_to_int(float128 a, float_status *status)
}
/*----------------------------------------------------------------------------
-| Returns the result of dividing the quadruple-precision floating-point value
-| `a' by the corresponding value `b'. The operation is performed according to
-| the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
-*----------------------------------------------------------------------------*/
-
-float128 float128_div(float128 a, float128 b, float_status *status)
-{
- bool aSign, bSign, zSign;
- int32_t aExp, bExp, zExp;
- uint64_t aSig0, aSig1, bSig0, bSig1, zSig0, zSig1, zSig2;
- uint64_t rem0, rem1, rem2, rem3, term0, term1, term2, term3;
-
- aSig1 = extractFloat128Frac1( a );
- aSig0 = extractFloat128Frac0( a );
- aExp = extractFloat128Exp( a );
- aSign = extractFloat128Sign( a );
- bSig1 = extractFloat128Frac1( b );
- bSig0 = extractFloat128Frac0( b );
- bExp = extractFloat128Exp( b );
- bSign = extractFloat128Sign( b );
- zSign = aSign ^ bSign;
- if ( aExp == 0x7FFF ) {
- if (aSig0 | aSig1) {
- return propagateFloat128NaN(a, b, status);
- }
- if ( bExp == 0x7FFF ) {
- if (bSig0 | bSig1) {
- return propagateFloat128NaN(a, b, status);
- }
- goto invalid;
- }
- return packFloat128( zSign, 0x7FFF, 0, 0 );
- }
- if ( bExp == 0x7FFF ) {
- if (bSig0 | bSig1) {
- return propagateFloat128NaN(a, b, status);
- }
- return packFloat128( zSign, 0, 0, 0 );
- }
- if ( bExp == 0 ) {
- if ( ( bSig0 | bSig1 ) == 0 ) {
- if ( ( aExp | aSig0 | aSig1 ) == 0 ) {
- invalid:
- float_raise(float_flag_invalid, status);
- return float128_default_nan(status);
- }
- float_raise(float_flag_divbyzero, status);
- return packFloat128( zSign, 0x7FFF, 0, 0 );
- }
- normalizeFloat128Subnormal( bSig0, bSig1, &bExp, &bSig0, &bSig1 );
- }
- if ( aExp == 0 ) {
- if ( ( aSig0 | aSig1 ) == 0 ) return packFloat128( zSign, 0, 0, 0 );
- normalizeFloat128Subnormal( aSig0, aSig1, &aExp, &aSig0, &aSig1 );
- }
- zExp = aExp - bExp + 0x3FFD;
- shortShift128Left(
- aSig0 | UINT64_C(0x0001000000000000), aSig1, 15, &aSig0, &aSig1 );
- shortShift128Left(
- bSig0 | UINT64_C(0x0001000000000000), bSig1, 15, &bSig0, &bSig1 );
- if ( le128( bSig0, bSig1, aSig0, aSig1 ) ) {
- shift128Right( aSig0, aSig1, 1, &aSig0, &aSig1 );
- ++zExp;
- }
- zSig0 = estimateDiv128To64( aSig0, aSig1, bSig0 );
- mul128By64To192( bSig0, bSig1, zSig0, &term0, &term1, &term2 );
- sub192( aSig0, aSig1, 0, term0, term1, term2, &rem0, &rem1, &rem2 );
- while ( (int64_t) rem0 < 0 ) {
- --zSig0;
- add192( rem0, rem1, rem2, 0, bSig0, bSig1, &rem0, &rem1, &rem2 );
- }
- zSig1 = estimateDiv128To64( rem1, rem2, bSig0 );
- if ( ( zSig1 & 0x3FFF ) <= 4 ) {
- mul128By64To192( bSig0, bSig1, zSig1, &term1, &term2, &term3 );
- sub192( rem1, rem2, 0, term1, term2, term3, &rem1, &rem2, &rem3 );
- while ( (int64_t) rem1 < 0 ) {
- --zSig1;
- add192( rem1, rem2, rem3, 0, bSig0, bSig1, &rem1, &rem2, &rem3 );
- }
- zSig1 |= ( ( rem1 | rem2 | rem3 ) != 0 );
- }
- shift128ExtraRightJamming( zSig0, zSig1, 0, 15, &zSig0, &zSig1, &zSig2 );
- return roundAndPackFloat128(zSign, zExp, zSig0, zSig1, zSig2, status);
-
-}
-
-/*----------------------------------------------------------------------------
| Returns the remainder of the quadruple-precision floating-point value `a'
| with respect to the corresponding value `b'. The operation is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
generated by cgit v1.1 at 2024-12-24 06:15:45 +0000