PageRenderTime 45ms CodeModel.GetById 13ms app.highlight 14ms RepoModel.GetById 1ms app.codeStats 0ms

/arch/mips/math-emu/sp_tlong.c

https://bitbucket.org/evzijst/gittest
C | 123 lines | 81 code | 11 blank | 31 comment | 32 complexity | 7497f7de0c04f247036e871bbe2a10bf MD5 | raw file
  1/* IEEE754 floating point arithmetic
  2 * single precision
  3 */
  4/*
  5 * MIPS floating point support
  6 * Copyright (C) 1994-2000 Algorithmics Ltd.
  7 * http://www.algor.co.uk
  8 *
  9 * ########################################################################
 10 *
 11 *  This program is free software; you can distribute it and/or modify it
 12 *  under the terms of the GNU General Public License (Version 2) as
 13 *  published by the Free Software Foundation.
 14 *
 15 *  This program is distributed in the hope it will be useful, but WITHOUT
 16 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 17 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 18 *  for more details.
 19 *
 20 *  You should have received a copy of the GNU General Public License along
 21 *  with this program; if not, write to the Free Software Foundation, Inc.,
 22 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 23 *
 24 * ########################################################################
 25 */
 26
 27
 28#include "ieee754sp.h"
 29
 30s64 ieee754sp_tlong(ieee754sp x)
 31{
 32	COMPXDP;		/* <-- need 64-bit mantissa tmp */
 33
 34	CLEARCX;
 35
 36	EXPLODEXSP;
 37	FLUSHXSP;
 38
 39	switch (xc) {
 40	case IEEE754_CLASS_SNAN:
 41	case IEEE754_CLASS_QNAN:
 42	case IEEE754_CLASS_INF:
 43		SETCX(IEEE754_INVALID_OPERATION);
 44		return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
 45	case IEEE754_CLASS_ZERO:
 46		return 0;
 47	case IEEE754_CLASS_DNORM:
 48	case IEEE754_CLASS_NORM:
 49		break;
 50	}
 51	if (xe >= 63) {
 52		/* look for valid corner case */
 53		if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
 54			return -0x8000000000000000LL;
 55		/* Set invalid. We will only use overflow for floating
 56		   point overflow */
 57		SETCX(IEEE754_INVALID_OPERATION);
 58		return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
 59	}
 60	/* oh gawd */
 61	if (xe > SP_MBITS) {
 62		xm <<= xe - SP_MBITS;
 63	} else if (xe < SP_MBITS) {
 64		u32 residue;
 65		int round;
 66		int sticky;
 67		int odd;
 68
 69		if (xe < -1) {
 70			residue = xm;
 71			round = 0;
 72			sticky = residue != 0;
 73			xm = 0;
 74		}
 75		else {
 76			residue = xm << (32 - SP_MBITS + xe);
 77			round = (residue >> 31) != 0;
 78			sticky = (residue << 1) != 0;
 79			xm >>= SP_MBITS - xe;
 80		}
 81		odd = (xm & 0x1) != 0x0;
 82		switch (ieee754_csr.rm) {
 83		case IEEE754_RN:
 84			if (round && (sticky || odd))
 85				xm++;
 86			break;
 87		case IEEE754_RZ:
 88			break;
 89		case IEEE754_RU:	/* toward +Infinity */
 90			if ((round || sticky) && !xs)
 91				xm++;
 92			break;
 93		case IEEE754_RD:	/* toward -Infinity */
 94			if ((round || sticky) && xs)
 95				xm++;
 96			break;
 97		}
 98		if ((xm >> 63) != 0) {
 99			/* This can happen after rounding */
100			SETCX(IEEE754_INVALID_OPERATION);
101			return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
102		}
103		if (round || sticky)
104			SETCX(IEEE754_INEXACT);
105	}
106	if (xs)
107		return -xm;
108	else
109		return xm;
110}
111
112
113u64 ieee754sp_tulong(ieee754sp x)
114{
115	ieee754sp hb = ieee754sp_1e63();
116
117	/* what if x < 0 ?? */
118	if (ieee754sp_lt(x, hb))
119		return (u64) ieee754sp_tlong(x);
120
121	return (u64) ieee754sp_tlong(ieee754sp_sub(x, hb)) |
122	    (1ULL << 63);
123}