diff options
Diffstat (limited to 'gdtoa/g_ddfmt.c')
| -rw-r--r-- | gdtoa/g_ddfmt.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/gdtoa/g_ddfmt.c b/gdtoa/g_ddfmt.c new file mode 100644 index 00000000..7fc30578 --- /dev/null +++ b/gdtoa/g_ddfmt.c @@ -0,0 +1,154 @@ +/**************************************************************** + +The author of this software is David M. Gay. + +Copyright (C) 1998 by Lucent Technologies +All Rights Reserved + +Permission to use, copy, modify, and distribute this software and +its documentation for any purpose and without fee is hereby +granted, provided that the above copyright notice appear in all +copies and that both that the copyright notice and this +permission notice and warranty disclaimer appear in supporting +documentation, and that the name of Lucent or any of its entities +not be used in advertising or publicity pertaining to +distribution of the software without specific, written prior +permission. + +LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, +INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. +IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY +SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER +IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, +ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF +THIS SOFTWARE. + +****************************************************************/ + +/* Please send bug reports to David M. Gay (dmg@acm.org). */ + +#include "gdtoaimp.h" +#include <string.h> + + char * +#ifdef KR_headers +g_ddfmt(buf, dd, ndig, bufsize) char *buf; double *dd; int ndig; unsigned bufsize; +#else +g_ddfmt(char *buf, double *dd, int ndig, unsigned bufsize) +#endif +{ + 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 < 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 < (int)(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, z->sign); + Bfree(z); + return b; + } |