WebSVN – HelenOS – Diff – /tags/0.4.1/kernel/genarch/src/softint/division.c


/*
 * Copyright (c) 2006 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.
 */
 
/** @addtogroup genarch
 * @{
 */
/** @file
 */
 
#include <genarch/softint/division.h>
 
#define ABSVAL(x) ((x) > 0 ? (x) : -(x))
#define SGN(x) ((x) >= 0 ? 1 : 0)
                     
static unsigned int divandmod32(unsigned int a, unsigned int b,
    unsigned int *remainder)
{
    unsigned int result;
    int steps = sizeof(unsigned int) * 8;
   
    *remainder = 0;
    result = 0;
   
    if (b == 0) {
        /* FIXME: division by zero */
        return 0;
    }
   
    if (a < b) {
        *remainder = a;
        return 0;
    }
 
    for (; steps > 0; steps--) {
        /* shift one bit to remainder */
        *remainder = ((*remainder) << 1) | (( a >> 31) & 0x1);
        result <<= 1;
       
        if (*remainder >= b) {
            *remainder -= b;
            result |= 0x1;
        }
        a <<= 1;
    }
 
    return result;
}
 
 
static unsigned long long divandmod64(unsigned long long a,
    unsigned long long b, unsigned long long *remainder)
{
    unsigned long long result;
    int steps = sizeof(unsigned long long) * 8;
   
    *remainder = 0;
    result = 0;
   
    if (b == 0) {
        /* FIXME: division by zero */
        return 0;
    }
   
    if (a < b) {
        *remainder = a;
        return 0;
    }
 
    for (; steps > 0; steps--) {
        /* shift one bit to remainder */
        *remainder = ((*remainder) << 1) | ((a >> 63) & 0x1);
        result <<= 1;
       
        if (*remainder >= b) {
            *remainder -= b;
            result |= 0x1;
        }
        a <<= 1;
    }
 
    return result;
}
 
/* 32bit integer division */
int __divsi3(int a, int b)
{
    unsigned int rem;
    int result;
   
    result = (int) divandmod32(ABSVAL(a), ABSVAL(b), &rem);
 
    if (SGN(a) == SGN(b))
        return result;
    return -result;
}
 
/* 64bit integer division */
long long __divdi3(long long a, long long b)
{
    unsigned long long rem;
    long long result;
   
    result = (long long) divandmod64(ABSVAL(a), ABSVAL(b), &rem);
 
    if (SGN(a) == SGN(b))
        return result;
    return -result;
}
 
/* 32bit unsigned integer division */
unsigned int __udivsi3(unsigned int a, unsigned int b)
{
    unsigned int rem;
    return divandmod32(a, b, &rem);
}
 
/* 64bit unsigned integer division */
unsigned long long __udivdi3(unsigned long long a, unsigned long long b)
{
    unsigned long long  rem;
    return divandmod64(a, b, &rem);
}
 
/* 32bit remainder of the signed division */
int __modsi3(int a, int b)
{
    unsigned int rem;
    divandmod32(a, b, &rem);
   
    /* if divident is negative, remainder must be too */
    if (!(SGN(a))) {
        return -((int) rem);
    }
   
    return (int) rem;
}
 
/* 64bit remainder of the signed division */
long long __moddi3(long long a,long  long b)
{
    unsigned long long rem;
    divandmod64(a, b, &rem);
   
    /* if divident is negative, remainder must be too */
    if (!(SGN(a))) {
        return -((long long) rem);
    }
   
    return (long long) rem;
}
 
/* 32bit remainder of the unsigned division */
unsigned int __umodsi3(unsigned int a, unsigned int b)
{
    unsigned int rem;
    divandmod32(a, b, &rem);
    return rem;
}
 
/* 64bit remainder of the unsigned division */
unsigned long long __umoddi3(unsigned long long a, unsigned long long b)
{
    unsigned long long rem;
    divandmod64(a, b, &rem);
    return rem;
}
 
unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b,
    unsigned long long *c)
{
    return divandmod64(a, b, c);
}
 
/** @}
 */
 

Rev 2505	Rev 4687
1	/*	1	/*
2	* Copyright (c) 2006 Josef Cejka	2	* Copyright (c) 2006 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	/** @addtogroup genarch	29	/** @addtogroup genarch
30	* @{	30	* @{
31	*/	31	*/
32	/** @file	32	/** @file
33	*/	33	*/
34		34
35	#include <genarch/softint/division.h>	35	#include <genarch/softint/division.h>
36		36
37	#define ABSVAL(x) ((x) > 0 ? (x) : -(x))	37	#define ABSVAL(x) ((x) > 0 ? (x) : -(x))
38	#define SGN(x) ((x) >= 0 ? 1 : 0)	38	#define SGN(x) ((x) >= 0 ? 1 : 0)
39		39
40	static unsigned int divandmod32(unsigned int a, unsigned int b,	40	static unsigned int divandmod32(unsigned int a, unsigned int b,
41	unsigned int *remainder)	41	unsigned int *remainder)
42	{	42	{
43	unsigned int result;	43	unsigned int result;
44	int steps = sizeof(unsigned int) * 8;	44	int steps = sizeof(unsigned int) * 8;
45		45
46	*remainder = 0;	46	*remainder = 0;
47	result = 0;	47	result = 0;
48		48
49	if (b == 0) {	49	if (b == 0) {
50	/* FIXME: division by zero */	50	/* FIXME: division by zero */
51	return 0;	51	return 0;
52	}	52	}
53		53
54	if (a < b) {	54	if (a < b) {
55	*remainder = a;	55	*remainder = a;
56	return 0;	56	return 0;
57	}	57	}
58		58
59	for (; steps > 0; steps--) {	59	for (; steps > 0; steps--) {
60	/* shift one bit to remainder */	60	/* shift one bit to remainder */
61	remainder = ((remainder) << 1) \| (( a >> 31) & 0x1);	61	remainder = ((remainder) << 1) \| (( a >> 31) & 0x1);
62	result <<= 1;	62	result <<= 1;
63		63
64	if (*remainder >= b) {	64	if (*remainder >= b) {
65	*remainder -= b;	65	*remainder -= b;
66	result \|= 0x1;	66	result \|= 0x1;
67	}	67	}
68	a <<= 1;	68	a <<= 1;
69	}	69	}
70		70
71	return result;	71	return result;
72	}	72	}
73		73
74		74
75	static unsigned long long divandmod64(unsigned long long a,	75	static unsigned long long divandmod64(unsigned long long a,
76	unsigned long long b, unsigned long long *remainder)	76	unsigned long long b, unsigned long long *remainder)
77	{	77	{
78	unsigned long long result;	78	unsigned long long result;
79	int steps = sizeof(unsigned long long) * 8;	79	int steps = sizeof(unsigned long long) * 8;
80		80
81	*remainder = 0;	81	*remainder = 0;
82	result = 0;	82	result = 0;
83		83
84	if (b == 0) {	84	if (b == 0) {
85	/* FIXME: division by zero */	85	/* FIXME: division by zero */
86	return 0;	86	return 0;
87	}	87	}
88		88
89	if (a < b) {	89	if (a < b) {
90	*remainder = a;	90	*remainder = a;
91	return 0;	91	return 0;
92	}	92	}
93		93
94	for (; steps > 0; steps--) {	94	for (; steps > 0; steps--) {
95	/* shift one bit to remainder */	95	/* shift one bit to remainder */
96	remainder = ((remainder) << 1) \| ((a >> 63) & 0x1);	96	remainder = ((remainder) << 1) \| ((a >> 63) & 0x1);
97	result <<= 1;	97	result <<= 1;
98		98
99	if (*remainder >= b) {	99	if (*remainder >= b) {
100	*remainder -= b;	100	*remainder -= b;
101	result \|= 0x1;	101	result \|= 0x1;
102	}	102	}
103	a <<= 1;	103	a <<= 1;
104	}	104	}
105		105
106	return result;	106	return result;
107	}	107	}
108		108
109	/* 32bit integer division */	109	/* 32bit integer division */
110	int __divsi3(int a, int b)	110	int __divsi3(int a, int b)
111	{	111	{
112	unsigned int rem;	112	unsigned int rem;
113	int result;	113	int result;
114		114
115	result = (int) divandmod32(ABSVAL(a), ABSVAL(b), &rem);	115	result = (int) divandmod32(ABSVAL(a), ABSVAL(b), &rem);
116		116
117	if (SGN(a) == SGN(b))	117	if (SGN(a) == SGN(b))
118	return result;	118	return result;
119	return -result;	119	return -result;
120	}	120	}
121		121
122	/* 64bit integer division */	122	/* 64bit integer division */
123	long long __divdi3(long long a, long long b)	123	long long __divdi3(long long a, long long b)
124	{	124	{
125	unsigned long long rem;	125	unsigned long long rem;
126	long long result;	126	long long result;
127		127
128	result = (long long) divandmod64(ABSVAL(a), ABSVAL(b), &rem);	128	result = (long long) divandmod64(ABSVAL(a), ABSVAL(b), &rem);
129		129
130	if (SGN(a) == SGN(b))	130	if (SGN(a) == SGN(b))
131	return result;	131	return result;
132	return -result;	132	return -result;
133	}	133	}
134		134
135	/* 32bit unsigned integer division */	135	/* 32bit unsigned integer division */
136	unsigned int __udivsi3(unsigned int a, unsigned int b)	136	unsigned int __udivsi3(unsigned int a, unsigned int b)
137	{	137	{
138	unsigned int rem;	138	unsigned int rem;
139	return divandmod32(a, b, &rem);	139	return divandmod32(a, b, &rem);
140	}	140	}
141		141
142	/* 64bit unsigned integer division */	142	/* 64bit unsigned integer division */
143	unsigned long long __udivdi3(unsigned long long a, unsigned long long b)	143	unsigned long long __udivdi3(unsigned long long a, unsigned long long b)
144	{	144	{
145	unsigned long long rem;	145	unsigned long long rem;
146	return divandmod64(a, b, &rem);	146	return divandmod64(a, b, &rem);
147	}	147	}
148		148
149	/* 32bit remainder of the signed division */	149	/* 32bit remainder of the signed division */
150	int __modsi3(int a, int b)	150	int __modsi3(int a, int b)
151	{	151	{
152	unsigned int rem;	152	unsigned int rem;
153	divandmod32(a, b, &rem);	153	divandmod32(a, b, &rem);
154		154
155	/* if divident is negative, remainder must be too */	155	/* if divident is negative, remainder must be too */
156	if (!(SGN(a))) {	156	if (!(SGN(a))) {
157	return -((int) rem);	157	return -((int) rem);
158	}	158	}
159		159
160	return (int) rem;	160	return (int) rem;
161	}	161	}
162		162
163	/* 64bit remainder of the signed division */	163	/* 64bit remainder of the signed division */
164	long long __moddi3(long long a,long long b)	164	long long __moddi3(long long a,long long b)
165	{	165	{
166	unsigned long long rem;	166	unsigned long long rem;
167	divandmod64(a, b, &rem);	167	divandmod64(a, b, &rem);
168		168
169	/* if divident is negative, remainder must be too */	169	/* if divident is negative, remainder must be too */
170	if (!(SGN(a))) {	170	if (!(SGN(a))) {
171	return -((long long) rem);	171	return -((long long) rem);
172	}	172	}
173		173
174	return (long long) rem;	174	return (long long) rem;
175	}	175	}
176		176
177	/* 32bit remainder of the unsigned division */	177	/* 32bit remainder of the unsigned division */
178	unsigned int __umodsi3(unsigned int a, unsigned int b)	178	unsigned int __umodsi3(unsigned int a, unsigned int b)
179	{	179	{
180	unsigned int rem;	180	unsigned int rem;
181	divandmod32(a, b, &rem);	181	divandmod32(a, b, &rem);
182	return rem;	182	return rem;
183	}	183	}
184		184
185	/* 64bit remainder of the unsigned division */	185	/* 64bit remainder of the unsigned division */
186	unsigned long long __umoddi3(unsigned long long a, unsigned long long b)	186	unsigned long long __umoddi3(unsigned long long a, unsigned long long b)
187	{	187	{
188	unsigned long long rem;	188	unsigned long long rem;
189	divandmod64(a, b, &rem);	189	divandmod64(a, b, &rem);
190	return rem;	190	return rem;
191	}	191	}
192		192
193	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b,	193	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b,
194	unsigned long long *c)	194	unsigned long long *c)
195	{	195	{
196	return divandmod64(a, b, c);	196	return divandmod64(a, b, c);
197	}	197	}
198		198
199	/** @}	199	/** @}
200	*/	200	*/
201		201

Subversion Repositories HelenOS

(root)/tags/0.4.1/kernel/genarch/src/softint/division.c – Rev 2505 → 4687