WebSVN – HelenOS – Diff – /trunk/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 1888	Rev 2071
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, unsigned int *remainder)	40	static unsigned int divandmod32(unsigned int a, unsigned int b, unsigned int *remainder)
41	{	41	{
42	unsigned int result;	42	unsigned int result;
43	int steps = sizeof(unsigned int) * 8;	43	int steps = sizeof(unsigned int) * 8;
44		44
45	*remainder = 0;	45	*remainder = 0;
46	result = 0;	46	result = 0;
47		47
48	if (b == 0) {	48	if (b == 0) {
49	/* FIXME: division by zero */	49	/* FIXME: division by zero */
50	return 0;	50	return 0;
51	}	51	}
52		52
53	if ( a < b) {	53	if ( a < b) {
54	*remainder = a;	54	*remainder = a;
55	return 0;	55	return 0;
56	}	56	}
57		57
58	for ( ; steps > 0; steps--) {	58	for ( ; steps > 0; steps--) {
59	/* shift one bit to remainder */	59	/* shift one bit to remainder */
60	remainder = ( (remainder) << 1) \| (( a >> 31) & 0x1);	60	remainder = ( (remainder) << 1) \| (( a >> 31) & 0x1);
61	result <<= 1;	61	result <<= 1;
62		62
63	if (*remainder >= b) {	63	if (*remainder >= b) {
64	*remainder -= b;	64	*remainder -= b;
65	result \|= 0x1;	65	result \|= 0x1;
66	}	66	}
67	a <<= 1;	67	a <<= 1;
68	}	68	}
69		69
70	return result;	70	return result;
71	}	71	}
72		72
73		73
74	static unsigned long long divandmod64(unsigned long long a, unsigned long long b, unsigned long long *remainder)	74	static unsigned long long divandmod64(unsigned long long a, unsigned long long b, unsigned long long *remainder)
75	{	75	{
76	unsigned long long result;	76	unsigned long long result;
77	int steps = sizeof(unsigned long long) * 8;	77	int steps = sizeof(unsigned long long) * 8;
78		78
79	*remainder = 0;	79	*remainder = 0;
80	result = 0;	80	result = 0;
81		81
82	if (b == 0) {	82	if (b == 0) {
83	/* FIXME: division by zero */	83	/* FIXME: division by zero */
84	return 0;	84	return 0;
85	}	85	}
86		86
87	if ( a < b) {	87	if ( a < b) {
88	*remainder = a;	88	*remainder = a;
89	return 0;	89	return 0;
90	}	90	}
91		91
92	for ( ; steps > 0; steps--) {	92	for ( ; steps > 0; steps--) {
93	/* shift one bit to remainder */	93	/* shift one bit to remainder */
94	remainder = ( (remainder) << 1) \| ((a >> 63) & 0x1);	94	remainder = ( (remainder) << 1) \| ((a >> 63) & 0x1);
95	result <<= 1;	95	result <<= 1;
96		96
97	if (*remainder >= b) {	97	if (*remainder >= b) {
98	*remainder -= b;	98	*remainder -= b;
99	result \|= 0x1;	99	result \|= 0x1;
100	}	100	}
101	a <<= 1;	101	a <<= 1;
102	}	102	}
103		103
104	return result;	104	return result;
105	}	105	}
106		106
107	/* 32bit integer division */	107	/* 32bit integer division */
108	int __divsi3(int a, int b)	108	int __divsi3(int a, int b)
109	{	109	{
110	unsigned int rem;	110	unsigned int rem;
111	int result;	111	int result;
112		112
113	result = (int)divandmod32(ABSVAL(a), ABSVAL(b), &rem);	113	result = (int)divandmod32(ABSVAL(a), ABSVAL(b), &rem);
114		114
115	if ( SGN(a) == SGN(b)) return result;	115	if ( SGN(a) == SGN(b)) return result;
116	return -result;	116	return -result;
117	}	117	}
118		118
119	/* 64bit integer division */	119	/* 64bit integer division */
120	long long __divdi3(long long a, long long b)	120	long long __divdi3(long long a, long long b)
121	{	121	{
122	unsigned long long rem;	122	unsigned long long rem;
123	long long result;	123	long long result;
124		124
125	result = (long long)divandmod64(ABSVAL(a), ABSVAL(b), &rem);	125	result = (long long)divandmod64(ABSVAL(a), ABSVAL(b), &rem);
126		126
127	if ( SGN(a) == SGN(b)) return result;	127	if ( SGN(a) == SGN(b)) return result;
128	return -result;	128	return -result;
129	}	129	}
130		130
131	/* 32bit unsigned integer division */	131	/* 32bit unsigned integer division */
132	unsigned int __udivsi3(unsigned int a, unsigned int b)	132	unsigned int __udivsi3(unsigned int a, unsigned int b)
133	{	133	{
134	unsigned int rem;	134	unsigned int rem;
135	return divandmod32(a, b, &rem);	135	return divandmod32(a, b, &rem);
136	}	136	}
137		137
138	/* 64bit unsigned integer division */	138	/* 64bit unsigned integer division */
139	unsigned long long __udivdi3(unsigned long long a, unsigned long long b)	139	unsigned long long __udivdi3(unsigned long long a, unsigned long long b)
140	{	140	{
141	unsigned long long rem;	141	unsigned long long rem;
142	return divandmod64(a, b, &rem);	142	return divandmod64(a, b, &rem);
143	}	143	}
144		144
145	/* 32bit remainder of the signed division */	145	/* 32bit remainder of the signed division */
146	int __modsi3(int a, int b)	146	int __modsi3(int a, int b)
147	{	147	{
148	unsigned int rem;	148	unsigned int rem;
149	divandmod32(a, b, &rem);	149	divandmod32(a, b, &rem);
150		150
151	/* if divident is negative, remainder must be too */	151	/* if divident is negative, remainder must be too */
152	if (!(SGN(a))) {	152	if (!(SGN(a))) {
153	return -((int)rem);	153	return -((int)rem);
154	}	154	}
155		155
156	return (int)rem;	156	return (int)rem;
157	}	157	}
158		158
159	/* 64bit remainder of the signed division */	159	/* 64bit remainder of the signed division */
160	long long __moddi3(long long a,long long b)	160	long long __moddi3(long long a,long long b)
161	{	161	{
162	unsigned long long rem;	162	unsigned long long rem;
163	divandmod64(a, b, &rem);	163	divandmod64(a, b, &rem);
164		164
165	/* if divident is negative, remainder must be too */	165	/* if divident is negative, remainder must be too */
166	if (!(SGN(a))) {	166	if (!(SGN(a))) {
167	return -((long long)rem);	167	return -((long long)rem);
168	}	168	}
169		169
170	return (long long)rem;	170	return (long long)rem;
171	}	171	}
172		172
173	/* 32bit remainder of the unsigned division */	173	/* 32bit remainder of the unsigned division */
174	unsigned int __umodsi3(unsigned int a, unsigned int b)	174	unsigned int __umodsi3(unsigned int a, unsigned int b)
175	{	175	{
176	unsigned int rem;	176	unsigned int rem;
177	divandmod32(a, b, &rem);	177	divandmod32(a, b, &rem);
178	return rem;	178	return rem;
179	}	179	}
180		180
181	/* 64bit remainder of the unsigned division */	181	/* 64bit remainder of the unsigned division */
182	unsigned long long __umoddi3(unsigned long long a, unsigned long long b)	182	unsigned long long __umoddi3(unsigned long long a, unsigned long long b)
183	{	183	{
184	unsigned long long rem;	184	unsigned long long rem;
185	divandmod64(a, b, &rem);	185	divandmod64(a, b, &rem);
186	return rem;	186	return rem;
187	}	187	}
188		188
189	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b, unsigned long long *c)	189	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b, unsigned long long *c)
190	{	190	{
191	return divandmod64(a, b, c);	191	return divandmod64(a, b, c);
192	}	192	}
193		193
194	/** @}	194	/** @}
195	*/	195	*/
196		196

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(root)/trunk/kernel/genarch/src/softint/division.c – Rev 1888 → 2071