g_ddfmt.c File Reference

#include "gdtoaimp.h"
#include <string.h>

Include dependency graph for g_ddfmt.c:

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Functions
char *	g_ddfmt (char *buf, double *dd, int ndig, unsigned bufsize)

Function Documentation

g_ddfmt()

char* g_ddfmt	(	char *	buf,
		double *	dd,
		int	ndig,
		unsigned	bufsize
	)

Definition at line 41 of file g_ddfmt.c.

{
    FPI fpi;
    char *b, *s, *se;
    ULong *L, bits0[4], *bits, *zx;
    int bx, by, decpt, ex, ey, i, j, mode;
    Bigint *x, *y, *z;
    double ddx[2];

    if(bufsize < 10 || bufsize < (unsigned)(ndig + 8))
    {
        {
            return 0;
        }
    }

    L = (ULong*)dd;
    if((L[_0] & 0x7ff00000L) == 0x7ff00000L)
    {
        /* Infinity or NaN */
        if(L[_0] & 0xfffff || L[_1])
        {
        nanret:
            return strcp(buf, "NaN");
        }
        if((L[2 + _0] & 0x7ff00000) == 0x7ff00000)
        {
            if(L[2 + _0] & 0xfffff || L[2 + _1])
            {
                {
                    goto nanret;
                }
            }
            if((L[_0] ^ L[2 + _0]) & 0x80000000L)
            {
                {
                    goto nanret; /* Infinity - Infinity */
                }
            }
        }
    infret:
        b = buf;
        if(L[_0] & 0x80000000L)
        {
            {
                *b++ = '-';
            }
        }
        return strcp(b, "Infinity");
    }
    if((L[2 + _0] & 0x7ff00000) == 0x7ff00000)
    {
        L += 2;
        if(L[_0] & 0xfffff || L[_1])
        {
            {
                goto nanret;
            }
        }
        goto infret;
    }
    if(dd[0] + dd[1] == 0.)
    {
        b = buf;
#ifndef IGNORE_ZERO_SIGN
        if(L[_0] & L[2 + _0] & 0x80000000L)
        {
            {
                *b++ = '-';
            }
        }
#endif
        *b++ = '0';
        *b = 0;
        return b;
    }
    if((L[_0] & 0x7ff00000L) < (L[2 + _0] & 0x7ff00000L))
    {
        ddx[1] = dd[0];
        ddx[0] = dd[1];
        dd = ddx;
        L = (ULong*)dd;
    }
    z = d2b(dd[0], &ex, &bx);
    if(dd[1] == 0.)
    {
        {
            goto no_y;
        }
    }
    x = z;
    y = d2b(dd[1], &ey, &by);
    if((i = ex - ey) != 0)
    {
        if(i > 0)
        {
            x = lshift(x, i);
            ex = ey;
        }
        else
        {
            {
                y = lshift(y, -i);
            }
        }
    }
    if((L[_0] ^ L[2 + _0]) & 0x80000000L)
    {
        z = diff(x, y);
        if(L[_0] & 0x80000000L)
        {
            {
                z->sign = 1 - z->sign;
            }
        }
    }
    else
    {
        z = sum(x, y);
        if(L[_0] & 0x80000000L)
        {
            {
                z->sign = 1;
            }
        }
    }
    Bfree(x);
    Bfree(y);
no_y:
    bits = zx = z->x;
    for(i = 0; !*zx; zx++)
    {
        {
            i += 32;
        }
    }
    i += lo0bits(zx);
    if(i)
    {
        rshift(z, i);
        ex += i;
    }
    fpi.nbits = z->wds * 32 - hi0bits(z->x[j = z->wds - 1]);
    if(fpi.nbits < 106)
    {
        fpi.nbits = 106;
        if(j < 3)
        {
            for(i = 0; i <= j; i++)
            {
                bits0[i] = bits[i];
            }
            while(i < 4)
            {
                bits0[i++] = 0;
            }
            bits = bits0;
        }
    }
    mode = 2;
    if(ndig <= 0)
    {
        if(bufsize < (unsigned)(fpi.nbits * .301029995664) + 10)
        {
            Bfree(z);
            return 0;
        }
        mode = 0;
    }
    fpi.emin = 1 - 1023 - 53 + 1;
    fpi.emax = 2046 - 1023 - 106 + 1;
    fpi.rounding = FPI_Round_near;
    fpi.sudden_underflow = 0;
    i = STRTOG_Normal;
    s = gdtoa(&fpi, ex, bits, &i, mode, ndig, &decpt, &se);
    b = g__fmt(buf, s, se, decpt, (ULong)z->sign);
    Bfree(z);
    return b;
}

References Bfree(), d2b(), diff(), FPI::emax, FPI::emin, FPI_Round_near, g__fmt(), gdtoa(), hi0bits, lo0bits(), lshift(), FPI::nbits, FPI::rounding, rshift(), Bigint::sign, strcp, STRTOG_Normal, FPI::sudden_underflow, sum(), Bigint::wds, and Bigint::x.