| 0,0 → 1,89 |
|---|
| /* |
| * Copyright (C) 2005 Josef Cejka |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include<sftypes.h> |
| #include<common.h> |
| |
| /** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions |
| * @param exp exponent with bias |
| * @param cfrac fraction shifted 10 places left with added hidden bit |
| * @return valied float64 |
| */ |
| float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign) |
| { |
| float64 result; |
| |
| result.parts.sign = sign; |
| |
| /* find first nonzero digit and shift result and detect possibly underflow */ |
| while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) { |
| cexp--; |
| cfrac <<= 1; |
| /* TODO: fix underflow */ |
| }; |
| |
| cfrac >>= 1; |
| ++cexp; |
| cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3)); |
| |
| if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) { |
| ++cexp; |
| cfrac >>= 1; |
| } |
| |
| /* check overflow */ |
| if (cexp >= FLOAT64_MAX_EXPONENT ) { |
| /* FIXME: overflow, return infinity */ |
| result.parts.exp = FLOAT64_MAX_EXPONENT; |
| result.parts.fraction = 0; |
| return result; |
| } |
| |
| if (cexp < 0) { |
| /* FIXME: underflow */ |
| result.parts.exp = 0; |
| if ((cexp + FLOAT64_FRACTION_SIZE) < 0) { |
| result.parts.fraction = 0; |
| return result; |
| } |
| cfrac >>= 1; |
| while (cexp < 0) { |
| cexp ++; |
| cfrac >>= 1; |
| } |
| return result; |
| |
| } else { |
| cexp ++; /*normalized*/ |
| result.parts.exp = (__u32)cexp; |
| } |
| |
| result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK)); |
| |
| return result; |
| } |