WebSVN – HelenOS-historic – Diff – /uspace/trunk/softfloat/generic/common.c


/*
 * 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 */
    };
   
 
 
    if ((cexp < 0) || ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) {
        /* FIXME: underflow */
        result.parts.exp = 0;
        if ((cexp + FLOAT64_FRACTION_SIZE + 1) < 0) { /* +1 is place for rounding */
            result.parts.fraction = 0;
            return result;
        }
       
        while (cexp < 0) {
            cexp++;
            cfrac >>= 1;
        }
   
        cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));
       
        if (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_HIDDEN_BIT_MASK - 1)))) {
           
            result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK));
 
            return result;
        }  
    } else {
        cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));
    }
   
    ++cexp;
 
    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;
    }
 
    result.parts.exp = (__u32)cexp;
   
    result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK));
   
    return result; 
}
 
 

Rev 834	Rev 835
1	/*	1	/*
2	* Copyright (C) 2005 Josef Cejka	2	* Copyright (C) 2005 Josef Cejka
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include<sftypes.h>	29	#include<sftypes.h>
30	#include<common.h>	30	#include<common.h>
31		31
32	/** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions	32	/** Take fraction shifted by 10 bits to left, round it, normalize it and detect exceptions
33	* @param exp exponent with bias	33	* @param exp exponent with bias
34	* @param cfrac fraction shifted 10 places left with added hidden bit	34	* @param cfrac fraction shifted 10 places left with added hidden bit
35	* @return valied float64	35	* @return valied float64
36	*/	36	*/
37	float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign)	37	float64 finishFloat64(__s32 cexp, __u64 cfrac, char sign)
38	{	38	{
39	float64 result;	39	float64 result;
40		40
41	result.parts.sign = sign;	41	result.parts.sign = sign;
42		42
43	/* find first nonzero digit and shift result and detect possibly underflow */	43	/* find first nonzero digit and shift result and detect possibly underflow */
44	while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) {	44	while ((cexp > 0) && (cfrac) && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ) )))) {
45	cexp--;	45	cexp--;
46	cfrac <<= 1;	46	cfrac <<= 1;
47	/* TODO: fix underflow */	47	/* TODO: fix underflow */
48	};	48	};
49		49
50	cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));	-
51		-
52	if ((cexp < 0) \|\| ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) {	50	if ((cexp < 0) \|\| ( cexp == 0 && (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1)))))) {
53	/* FIXME: underflow */	51	/* FIXME: underflow */
54	result.parts.exp = 0;	52	result.parts.exp = 0;
55	if ((cexp + FLOAT64_FRACTION_SIZE) < 0) {	53	if ((cexp + FLOAT64_FRACTION_SIZE + 1) < 0) { /* +1 is place for rounding */
56	result.parts.fraction = 0;	54	result.parts.fraction = 0;
57	return result;	55	return result;
58	}	56	}
59	//cfrac >>= 1;	57
60	while (cexp < 0) {	58	while (cexp < 0) {
61	cexp++;	59	cexp++;
62	cfrac >>= 1;	60	cfrac >>= 1;
63	}	61	}
-		62
-		63	cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));
-		64
-		65	if (!(cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_HIDDEN_BIT_MASK - 1)))) {
64		66
65	result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK));	67	result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2) ) & (~FLOAT64_HIDDEN_BIT_MASK));
66		-
67	return result;	68	return result;
-		69	}
-		70	} else {
-		71	cfrac += (0x1 << (64 - FLOAT64_FRACTION_SIZE - 3));
68	}	72	}
69		73
70	++cexp;	74	++cexp;
71		75
72	if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) {	76	if (cfrac & (FLOAT64_HIDDEN_BIT_MASK << (64 - FLOAT64_FRACTION_SIZE - 1 ))) {
73	++cexp;	77	++cexp;
74	cfrac >>= 1;	78	cfrac >>= 1;
75	}	79	}
76		80
77	/* check overflow */	81	/* check overflow */
78	if (cexp >= FLOAT64_MAX_EXPONENT ) {	82	if (cexp >= FLOAT64_MAX_EXPONENT ) {
79	/* FIXME: overflow, return infinity */	83	/* FIXME: overflow, return infinity */
80	result.parts.exp = FLOAT64_MAX_EXPONENT;	84	result.parts.exp = FLOAT64_MAX_EXPONENT;
81	result.parts.fraction = 0;	85	result.parts.fraction = 0;
82	return result;	86	return result;
83	}	87	}
84		88
85	result.parts.exp = (__u32)cexp;	89	result.parts.exp = (__u32)cexp;
86		90
87	result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK));	91	result.parts.fraction = ((cfrac >>(64 - FLOAT64_FRACTION_SIZE - 2 ) ) & (~FLOAT64_HIDDEN_BIT_MASK));
88		92
89	return result;	93	return result;
90	}	94	}
91		95
92		96

Subversion Repositories HelenOS-historic

(root)/uspace/trunk/softfloat/generic/common.c – Rev 834 → 835