[PATCH 36/72] softfloat: Move mul_floats to softfloat-parts.c.inc

[Richard Henderson <richard.henderson@linaro.org>]

Rename to parts$N_mul.
Reimplement float128_mul with FloatParts128.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 fpu/softfloat.c           | 206 ++++++++++++++------------------------
 fpu/softfloat-parts.c.inc |  51 ++++++++++
 2 files changed, 128 insertions(+), 129 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index f48e6b1f64..4f498c11e5 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -532,6 +532,16 @@ typedef struct {
     uint64_t frac_lo;
 } FloatParts128;
 
+typedef struct {
+    FloatClass cls;
+    bool sign;
+    int32_t exp;
+    uint64_t frac_hi;
+    uint64_t frac_hm;  /* high-middle */
+    uint64_t frac_lm;  /* low-middle */
+    uint64_t frac_lo;
+} FloatParts256;
+
 /* These apply to the most significant word of each FloatPartsN. */
 #define DECOMPOSED_BINARY_POINT    63
 #define DECOMPOSED_IMPLICIT_BIT    (1ull << DECOMPOSED_BINARY_POINT)
@@ -768,6 +778,14 @@ static FloatParts128 *parts128_addsub(FloatParts128 *a, FloatParts128 *b,
 #define parts_addsub(A, B, S, Z) \
     PARTS_GENERIC_64_128(addsub, A)(A, B, S, Z)
 
+static FloatParts64 *parts64_mul(FloatParts64 *a, FloatParts64 *b,
+                                 float_status *s);
+static FloatParts128 *parts128_mul(FloatParts128 *a, FloatParts128 *b,
+                                   float_status *s);
+
+#define parts_mul(A, B, S) \
+    PARTS_GENERIC_64_128(mul, A)(A, B, S)
+
 /*
  * Helper functions for softfloat-parts.c.inc, per-size operations.
  */
@@ -858,6 +876,19 @@ static bool frac128_eqz(FloatParts128 *a)
 
 #define frac_eqz(A)  FRAC_GENERIC_64_128(eqz, A)(A)
 
+static void frac64_mulw(FloatParts128 *r, FloatParts64 *a, FloatParts64 *b)
+{
+    mulu64(&r->frac_lo, &r->frac_hi, a->frac, b->frac);
+}
+
+static void frac128_mulw(FloatParts256 *r, FloatParts128 *a, FloatParts128 *b)
+{
+    mul128To256(a->frac_hi, a->frac_lo, b->frac_hi, b->frac_lo,
+                &r->frac_hi, &r->frac_hm, &r->frac_lm, &r->frac_lo);
+}
+
+#define frac_mulw(R, A, B)  FRAC_GENERIC_64_128(mulw, A)(R, A, B)
+
 static void frac64_neg(FloatParts64 *a)
 {
     a->frac = -a->frac;
@@ -954,23 +985,42 @@ static bool frac128_sub(FloatParts128 *r, FloatParts128 *a, FloatParts128 *b)
 
 #define frac_sub(R, A, B)  FRAC_GENERIC_64_128(sub, R)(R, A, B)
 
+static void frac64_truncjam(FloatParts64 *r, FloatParts128 *a)
+{
+    r->frac = a->frac_hi | (a->frac_lo != 0);
+}
+
+static void frac128_truncjam(FloatParts128 *r, FloatParts256 *a)
+{
+    r->frac_hi = a->frac_hi;
+    r->frac_lo = a->frac_hm | ((a->frac_lm | a->frac_lo) != 0);
+}
+
+#define frac_truncjam(R, A)  FRAC_GENERIC_64_128(truncjam, R)(R, A)
+
 #define partsN(NAME)   glue(glue(glue(parts,N),_),NAME)
 #define FloatPartsN    glue(FloatParts,N)
+#define FloatPartsW    glue(FloatParts,W)
 
 #define N 64
+#define W 128
 
 #include "softfloat-parts-addsub.c.inc"
 #include "softfloat-parts.c.inc"
 
 #undef  N
+#undef  W
 #define N 128
+#define W 256
 
 #include "softfloat-parts-addsub.c.inc"
 #include "softfloat-parts.c.inc"
 
 #undef  N
+#undef  W
 #undef  partsN
 #undef  FloatPartsN
+#undef  FloatPartsW
 
 /*
  * Pack/unpack routines with a specific FloatFmt.
@@ -1249,89 +1299,42 @@ float128 float128_sub(float128 a, float128 b, float_status *status)
 }
 
 /*
- * Returns the result of multiplying the floating-point values `a' and
- * `b'. The operation is performed according to the IEC/IEEE Standard
- * for Binary Floating-Point Arithmetic.
+ * Multiplication
  */
 
-static FloatParts64 mul_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 hi, lo;
-        int exp = a.exp + b.exp;
-
-        mul64To128(a.frac, b.frac, &hi, &lo);
-        if (hi & DECOMPOSED_IMPLICIT_BIT) {
-            exp += 1;
-        } else {
-            hi <<= 1;
-        }
-        hi |= (lo != 0);
-
-        /* Re-use a */
-        a.exp = exp;
-        a.sign = sign;
-        a.frac = hi;
-        return a;
-    }
-    /* handle all the NaN cases */
-    if (is_nan(a.cls) || is_nan(b.cls)) {
-        return *parts_pick_nan(&a, &b, s);
-    }
-    /* Inf * Zero == NaN */
-    if ((a.cls == float_class_inf && b.cls == float_class_zero) ||
-        (a.cls == float_class_zero && b.cls == float_class_inf)) {
-        float_raise(float_flag_invalid, s);
-        parts_default_nan(&a, s);
-        return a;
-    }
-    /* Multiply by 0 or Inf */
-    if (a.cls == float_class_inf || a.cls == float_class_zero) {
-        a.sign = sign;
-        return a;
-    }
-    if (b.cls == float_class_inf || b.cls == float_class_zero) {
-        b.sign = sign;
-        return b;
-    }
-    g_assert_not_reached();
-}
-
 float16 QEMU_FLATTEN float16_mul(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 = mul_floats(pa, pb, status);
+    pr = parts_mul(&pa, &pb, status);
 
-    return float16_round_pack_canonical(&pr, status);
+    return float16_round_pack_canonical(pr, status);
 }
 
 static float32 QEMU_SOFTFLOAT_ATTR
 soft_f32_mul(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 = mul_floats(pa, pb, status);
+    pr = parts_mul(&pa, &pb, status);
 
-    return float32_round_pack_canonical(&pr, status);
+    return float32_round_pack_canonical(pr, status);
 }
 
 static float64 QEMU_SOFTFLOAT_ATTR
 soft_f64_mul(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 = mul_floats(pa, pb, status);
+    pr = parts_mul(&pa, &pb, status);
 
-    return float64_round_pack_canonical(&pr, status);
+    return float64_round_pack_canonical(pr, status);
 }
 
 static float hard_f32_mul(float a, float b)
@@ -1358,20 +1361,28 @@ float64_mul(float64 a, float64 b, float_status *s)
                         f64_is_zon2, f64_addsubmul_post);
 }
 
-/*
- * Returns the result of multiplying the bfloat16
- * values `a' and `b'.
- */
-
-bfloat16 QEMU_FLATTEN bfloat16_mul(bfloat16 a, bfloat16 b, float_status *status)
+bfloat16 QEMU_FLATTEN
+bfloat16_mul(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 = mul_floats(pa, pb, status);
+    pr = parts_mul(&pa, &pb, status);
 
-    return bfloat16_round_pack_canonical(&pr, status);
+    return bfloat16_round_pack_canonical(pr, status);
+}
+
+float128 QEMU_FLATTEN
+float128_mul(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_mul(&pa, &pb, status);
+
+    return float128_round_pack_canonical(pr, status);
 }
 
 /*
@@ -7067,69 +7078,6 @@ float128 float128_round_to_int(float128 a, float_status *status)
 
 }
 
-/*----------------------------------------------------------------------------
-| Returns the result of multiplying the quadruple-precision floating-point
-| values `a' and `b'.  The operation is performed according to the IEC/IEEE
-| Standard for Binary Floating-Point Arithmetic.
-*----------------------------------------------------------------------------*/
-
-float128 float128_mul(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, zSig3;
-
-    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 )
-             || ( ( bExp == 0x7FFF ) && ( bSig0 | bSig1 ) ) ) {
-            return propagateFloat128NaN(a, b, status);
-        }
-        if ( ( bExp | bSig0 | bSig1 ) == 0 ) goto invalid;
-        return packFloat128( zSign, 0x7FFF, 0, 0 );
-    }
-    if ( bExp == 0x7FFF ) {
-        if (bSig0 | bSig1) {
-            return propagateFloat128NaN(a, b, status);
-        }
-        if ( ( aExp | aSig0 | aSig1 ) == 0 ) {
- invalid:
-            float_raise(float_flag_invalid, status);
-            return float128_default_nan(status);
-        }
-        return packFloat128( zSign, 0x7FFF, 0, 0 );
-    }
-    if ( aExp == 0 ) {
-        if ( ( aSig0 | aSig1 ) == 0 ) return packFloat128( zSign, 0, 0, 0 );
-        normalizeFloat128Subnormal( aSig0, aSig1, &aExp, &aSig0, &aSig1 );
-    }
-    if ( bExp == 0 ) {
-        if ( ( bSig0 | bSig1 ) == 0 ) return packFloat128( zSign, 0, 0, 0 );
-        normalizeFloat128Subnormal( bSig0, bSig1, &bExp, &bSig0, &bSig1 );
-    }
-    zExp = aExp + bExp - 0x4000;
-    aSig0 |= UINT64_C(0x0001000000000000);
-    shortShift128Left( bSig0, bSig1, 16, &bSig0, &bSig1 );
-    mul128To256( aSig0, aSig1, bSig0, bSig1, &zSig0, &zSig1, &zSig2, &zSig3 );
-    add128( zSig0, zSig1, aSig0, aSig1, &zSig0, &zSig1 );
-    zSig2 |= ( zSig3 != 0 );
-    if (UINT64_C( 0x0002000000000000) <= zSig0 ) {
-        shift128ExtraRightJamming(
-            zSig0, zSig1, zSig2, 1, &zSig0, &zSig1, &zSig2 );
-        ++zExp;
-    }
-    return roundAndPackFloat128(zSign, zExp, zSig0, zSig1, zSig2, status);
-
-}
-
 /*----------------------------------------------------------------------------
 | Returns the result of dividing the quadruple-precision floating-point value
 | `a' by the corresponding value `b'.  The operation is performed according to
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index cfce9f6421..9a67ab2bea 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -362,3 +362,54 @@ static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b,
  p_nan:
     return parts_pick_nan(a, b, s);
 }
+
+/*
+ * Returns the result of multiplying the floating-point values `a' and
+ * `b'. The operation is performed according to the IEC/IEEE Standard
+ * for Binary Floating-Point Arithmetic.
+ */
+static FloatPartsN *partsN(mul)(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)) {
+        FloatPartsW tmp;
+
+        frac_mulw(&tmp, a, b);
+        frac_truncjam(a, &tmp);
+
+        a->exp += b->exp + 1;
+        if (!(a->frac_hi & DECOMPOSED_IMPLICIT_BIT)) {
+            frac_add(a, a, a);
+            a->exp -= 1;
+        }
+
+        a->sign = sign;
+        return a;
+    }
+
+    /* Inf * Zero == NaN */
+    if (unlikely(ab_mask == float_cmask_infzero)) {
+        float_raise(float_flag_invalid, s);
+        parts_default_nan(a, s);
+        return a;
+    }
+
+    if (unlikely(ab_mask & float_cmask_anynan)) {
+        return parts_pick_nan(a, b, s);
+    }
+
+    /* Multiply by 0 or Inf */
+    if (ab_mask & float_cmask_inf) {
+        a->cls = float_class_inf;
+        a->sign = sign;
+        return a;
+    }
+
+    g_assert(ab_mask & float_cmask_zero);
+    a->cls = float_class_zero;
+    a->sign = sign;
+    return a;
+}
-- 
2.25.1