jsdtoa.c

java script test programing source code

#ifdef __STDC__
                rv = HUGE_VAL;
#else
                /* Can't trust HUGE_VAL */
                set_word0(rv, Exp_mask);
                set_word1(rv, 0);
#endif
                if (bd0)
                    goto retfree;
                goto ret;
            }
            e1 >>= 4;
            for(j = 0; e1 > 1; j++, e1 >>= 1)
                if (e1 & 1)
                    rv *= bigtens[j];
            /* The last multiplication could overflow. */
            set_word0(rv, word0(rv) - P*Exp_msk1);
            rv *= bigtens[j];
            if ((z = word0(rv) & Exp_mask) > Exp_msk1*(DBL_MAX_EXP+Bias-P))
                goto ovfl;
            if (z > Exp_msk1*(DBL_MAX_EXP+Bias-1-P)) {
                /* set to largest number */
                /* (Can't trust DBL_MAX) */
                set_word0(rv, Big0);
                set_word1(rv, Big1);
                }
            else
                set_word0(rv, word0(rv) + P*Exp_msk1);
            }
    }
    else if (e1 < 0) {
        e1 = -e1;
        if ((i = e1 & 15) != 0)
            rv /= tens[i];
        if (e1 &= ~15) {
            e1 >>= 4;
            if (e1 >= 1 << n_bigtens)
                goto undfl;
#ifdef Avoid_Underflow
            if (e1 & Scale_Bit)
                scale = P;
            for(j = 0; e1 > 0; j++, e1 >>= 1)
                if (e1 & 1)
                    rv *= tinytens[j];
            if (scale && (j = P + 1 - ((word0(rv) & Exp_mask)
                        >> Exp_shift)) > 0) {
                /* scaled rv is denormal; zap j low bits */
                if (j >= 32) {
                    set_word1(rv, 0);
                    set_word0(rv, word0(rv) & (0xffffffff << (j-32)));
                    if (!word0(rv))
                        set_word0(rv, 1);
                    }
                else
                    set_word1(rv, word1(rv) & (0xffffffff << j));
                }
#else
            for(j = 0; e1 > 1; j++, e1 >>= 1)
                if (e1 & 1)
                    rv *= tinytens[j];
            /* The last multiplication could underflow. */
            rv0 = rv;
            rv *= tinytens[j];
            if (!rv) {
                rv = 2.*rv0;
                rv *= tinytens[j];
#endif
                if (!rv) {
                undfl:
                    rv = 0.;
                    *err = JS_DTOA_ERANGE;
                    if (bd0)
                        goto retfree;
                    goto ret;
                }
#ifndef Avoid_Underflow
                set_word0(rv, Tiny0);
                set_word1(rv, Tiny1);
                /* The refinement below will clean
                 * this approximation up.
                 */
            }
#endif
        }
    }

    /* Now the hard part -- adjusting rv to the correct value.*/

    /* Put digits into bd: true value = bd * 10^e */

    bd0 = s2b(s0, nd0, nd, y);
    if (!bd0)
        goto nomem;

    for(;;) {
        bd = Balloc(bd0->k);
        if (!bd)
            goto nomem;
        Bcopy(bd, bd0);
        bb = d2b(rv, &bbe, &bbbits);    /* rv = bb * 2^bbe */
        if (!bb)
            goto nomem;
        bs = i2b(1);
        if (!bs)
            goto nomem;

        if (e >= 0) {
            bb2 = bb5 = 0;
            bd2 = bd5 = e;
        }
        else {
            bb2 = bb5 = -e;
            bd2 = bd5 = 0;
        }
        if (bbe >= 0)
            bb2 += bbe;
        else
            bd2 -= bbe;
        bs2 = bb2;
#ifdef Sudden_Underflow
        j = P + 1 - bbbits;
#else
#ifdef Avoid_Underflow
        j = bbe - scale;
#else
        j = bbe;
#endif
        i = j + bbbits - 1; /* logb(rv) */
        if (i < Emin)   /* denormal */
            j += P - Emin;
        else
            j = P + 1 - bbbits;
#endif
        bb2 += j;
        bd2 += j;
#ifdef Avoid_Underflow
        bd2 += scale;
#endif
        i = bb2 < bd2 ? bb2 : bd2;
        if (i > bs2)
            i = bs2;
        if (i > 0) {
            bb2 -= i;
            bd2 -= i;
            bs2 -= i;
        }
        if (bb5 > 0) {
            bs = pow5mult(bs, bb5);
            if (!bs)
                goto nomem;
            bb1 = mult(bs, bb);
            if (!bb1)
                goto nomem;
            Bfree(bb);
            bb = bb1;
        }
        if (bb2 > 0) {
            bb = lshift(bb, bb2);
            if (!bb)
                goto nomem;
        }
        if (bd5 > 0) {
            bd = pow5mult(bd, bd5);
            if (!bd)
                goto nomem;
        }
        if (bd2 > 0) {
            bd = lshift(bd, bd2);
            if (!bd)
                goto nomem;
        }
        if (bs2 > 0) {
            bs = lshift(bs, bs2);
            if (!bs)
                goto nomem;
        }
        delta = diff(bb, bd);
        if (!delta)
            goto nomem;
        dsign = delta->sign;
        delta->sign = 0;
        i = cmp(delta, bs);
        if (i < 0) {
            /* Error is less than half an ulp -- check for
             * special case of mantissa a power of two.
             */
            if (dsign || word1(rv) || word0(rv) & Bndry_mask
#ifdef Avoid_Underflow
             || (word0(rv) & Exp_mask) <= Exp_msk1 + P*Exp_msk1
#else
             || (word0(rv) & Exp_mask) <= Exp_msk1
#endif
                ) {
#ifdef Avoid_Underflow
                if (!delta->x[0] && delta->wds == 1)
                    dsign = 2;
#endif
                break;
                }
            delta = lshift(delta,Log2P);
            if (!delta)
                goto nomem;
            if (cmp(delta, bs) > 0)
                goto drop_down;
            break;
        }
        if (i == 0) {
            /* exactly half-way between */
            if (dsign) {
                if ((word0(rv) & Bndry_mask1) == Bndry_mask1
                    &&  word1(rv) == 0xffffffff) {
                    /*boundary case -- increment exponent*/
                    set_word0(rv, (word0(rv) & Exp_mask) + Exp_msk1);
                    set_word1(rv, 0);
#ifdef Avoid_Underflow
                    dsign = 0;
#endif
                    break;
                }
            }
            else if (!(word0(rv) & Bndry_mask) && !word1(rv)) {
#ifdef Avoid_Underflow
                dsign = 2;
#endif
            drop_down:
                /* boundary case -- decrement exponent */
#ifdef Sudden_Underflow
                L = word0(rv) & Exp_mask;
                if (L <= Exp_msk1)
                    goto undfl;
                L -= Exp_msk1;
#else
                L = (word0(rv) & Exp_mask) - Exp_msk1;
#endif
                set_word0(rv, L | Bndry_mask1);
                set_word1(rv, 0xffffffff);
                break;
            }
#ifndef ROUND_BIASED
            if (!(word1(rv) & LSB))
                break;
#endif
            if (dsign)
                rv += ulp(rv);
#ifndef ROUND_BIASED
            else {
                rv -= ulp(rv);
#ifndef Sudden_Underflow
                if (!rv)
                    goto undfl;
#endif
            }
#ifdef Avoid_Underflow
            dsign = 1 - dsign;
#endif
#endif
            break;
        }
        if ((aadj = ratio(delta, bs)) <= 2.) {
            if (dsign)
                aadj = aadj1 = 1.;
            else if (word1(rv) || word0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
                if (word1(rv) == Tiny1 && !word0(rv))
                    goto undfl;
#endif
                aadj = 1.;
                aadj1 = -1.;
            }
            else {
                /* special case -- power of FLT_RADIX to be */
                /* rounded down... */

                if (aadj < 2./FLT_RADIX)
                    aadj = 1./FLT_RADIX;
                else
                    aadj *= 0.5;
                aadj1 = -aadj;
            }
        }
        else {
            aadj *= 0.5;
            aadj1 = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
            switch(FLT_ROUNDS) {
            case 2: /* towards +infinity */
                aadj1 -= 0.5;
                break;
            case 0: /* towards 0 */
            case 3: /* towards -infinity */
                aadj1 += 0.5;
            }
#else
            if (FLT_ROUNDS == 0)
                aadj1 += 0.5;
#endif
        }
        y = word0(rv) & Exp_mask;

        /* Check for overflow */

        if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
            rv0 = rv;
            set_word0(rv, word0(rv) - P*Exp_msk1);
            adj = aadj1 * ulp(rv);
            rv += adj;
            if ((word0(rv) & Exp_mask) >=
                Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
                if (word0(rv0) == Big0 && word1(rv0) == Big1)
                    goto ovfl;
                set_word0(rv, Big0);
                set_word1(rv, Big1);
                goto cont;
            }
            else
                set_word0(rv, word0(rv) + P*Exp_msk1);
        }
        else {
#ifdef Sudden_Underflow
            if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
                rv0 = rv;
                set_word0(rv, word0(rv) + P*Exp_msk1);
                adj = aadj1 * ulp(rv);
                rv += adj;
                    if ((word0(rv) & Exp_mask) <= P*Exp_msk1)
                        {
                            if (word0(rv0) == Tiny0
                                && word1(rv0) == Tiny1)
                                goto undfl;
                            set_word0(rv, Tiny0);
                            set_word1(rv, Tiny1);
                            goto cont;
                        }
                    else
                        set_word0(rv, word0(rv) - P*Exp_msk1);
            }
            else {
                adj = aadj1 * ulp(rv);
                rv += adj;
            }
#else
            /* Compute adj so that the IEEE rounding rules will
             * correctly round rv + adj in some half-way cases.
             * If rv * ulp(rv) is denormalized (i.e.,
             * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid
             * trouble from bits lost to denormalization;
             * example: 1.2e-307 .
             */
#ifdef Avoid_Underflow
            if (y <= P*Exp_msk1 && aadj > 1.)
#else
            if (y <= (P-1)*Exp_msk1 && aadj > 1.)
#endif
                {
                aadj1 = (double)(int32)(aadj + 0.5);
                if (!dsign)
                    aadj1 = -aadj1;
            }
#ifdef Avoid_Underflow
            if (scale && y <= P*Exp_msk1)
                set_word0(aadj1, word0(aadj1) + (P+1)*Exp_msk1 - y);
#endif
            adj = aadj1 * ulp(rv);
            rv += adj;
#endif
        }
        z = word0(rv) & Exp_mask;
#ifdef Avoid_Underflow
        if (!scale)
#endif
        if (y == z) {
            /* Can we stop now? */
            L = (Long)aadj;
            aadj -= L;
            /* The tolerances below are conservative. */
            if (dsign || word1(rv) || word0(rv) & Bndry_mask) {
                if (aadj < .4999999 || aadj > .5000001)
                    break;
            }
            else if (aadj < .4999999/FLT_RADIX)
                break;
        }
    cont:
        Bfree(bb);
        Bfree(bd);
        Bfree(bs);
        Bfree(delta);
        bb = bd = bs = delta = NULL;
    }
#ifdef Avoid_Underflow
    if (scale) {
        rv0 = 0.;
        set_word0(rv0, Exp_1 - P*Exp_msk1);
        set_word1(rv0, 0);
        if ((word0(rv) & Exp_mask) <= P*Exp_msk1
              && word1(rv) & 1
              && dsign != 2) {
            if (dsign) {
#ifdef Sudden_Underflow
                /* rv will be 0, but this would give the  */
                /* right result if only rv *= rv0 worked. */
                set_word0(rv, word0(rv) + P*Exp_msk1);
                set_word0(rv0, Exp_1 - 2*P*Exp_msk1);
#endif
                rv += ulp(rv);
                }
            else
                set_word1(rv, word1(rv) & ~1);
        }
        rv *= rv0;
    }
#endif /* Avoid_Underflow */
retfree:
    Bfree(bb);
    Bfree(bd);
    Bfree(bs);
    Bfree(bd0);
    Bfree(delta);
ret:
    RELEASE_DTOA_LOCK();
    if (se)
        *se = (char *)s;
    return sign ? -rv : rv;

nomem:
    Bfree(bb);
    Bfree(bd);
    Bfree(bs);
    Bfree(bd0);
    Bfree(delta);
    RELEASE_DTOA_LOCK();
    *err = JS_DTOA_ENOMEM;
    return 0;
}


/* Return floor(b/2^k) and set b to be the remainder.  The returned quotient must be less than 2^32. */
static uint32 quorem2(Bigint *b, int32 k)
{
    ULong mask;
    ULong result;
    ULong *bx, *bxe;
    int32 w;
    int32 n = k >> 5;
    k &= 0x1F;
    mask = (1<<k) - 1;

    w = b->wds - n;
    if (w <= 0)
        return 0;
    JS_ASSERT(w <= 2);
    bx = b->x;
    bxe = bx + n;
    result = *bxe >> k;
    *bxe &= mask;
    if (w == 2) {
        JS_ASSERT(!(bxe[1] & ~mask));
        if (k)
            result |= bxe[1] << (32 - k);
    }
    n++;
    while (!*bxe && bxe != bx) {
        n--;
        bxe--;
    }
    b->wds = n;
    return result;
}

/* Return floor(b/S) and set b to be the remainder.  As added restrictions, b must not have
 * more words than S, the most significant word of S must not start with a 1 bit, and the
 * returned quotient must be less than 36. */
static int32 quorem(Bigint *b, Bigint *S)
{
    int32 n;
    ULong *bx, *bxe, q, *sx, *sxe;
#ifdef ULLong
    ULLong borrow, carry, y, ys;
#else