WebSVN – HelenOS-historic – Diff – /kernel/trunk/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.
 */
 
#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 divandmod64(unsigned long a, unsigned long b, unsigned long *remainder)
{
    unsigned long result;
    int steps = sizeof(unsigned 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 __divdi3(long a, long b)
{
    unsigned long rem;
    long result;
   
    result = (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 __udivdi3(unsigned long a, unsigned long b)
{
    unsigned 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 __moddi3(long a, long b)
{
    unsigned long rem;
    divandmod64(a, b, &rem);
   
    /* if divident is negative, remainder must be too */
    if (!(SGN(a))) {
        return -((long)rem);
    }
   
    return (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 __umoddi3(unsigned long a, unsigned long b)
{
    unsigned long rem;
    divandmod64(a, b, &rem);
    return rem;
}
 
unsigned long __udivmoddi3(unsigned long a, unsigned long b, unsigned long *c)
{
    return divandmod64(a, b, c);
}
 
 
 

Rev 810	Rev 811
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	#include <softint/softint.h>	29	#include <genarch/softint/division.h>
30		30
31	#define ABSVAL(x) ( (x) > 0 ? (x) : -(x))	31	#define ABSVAL(x) ( (x) > 0 ? (x) : -(x))
32	#define SGN(x) ( (x) >= 0 ? 1 : 0 )	32	#define SGN(x) ( (x) >= 0 ? 1 : 0 )
33		33
34	static unsigned int divandmod32(unsigned int a, unsigned int b, unsigned int *remainder)	34	static unsigned int divandmod32(unsigned int a, unsigned int b, unsigned int *remainder)
35	{	35	{
36	unsigned int result;	36	unsigned int result;
37	int steps = sizeof(unsigned int);	37	int steps = sizeof(unsigned int) * 8;
38		38
39	*remainder = 0;	39	*remainder = 0;
40	result = 0;	40	result = 0;
41		41
42	if (b == 0) {	42	if (b == 0) {
43	/* FIXME: division by zero */	43	/* FIXME: division by zero */
44	return 0;	44	return 0;
45	}	45	}
46		46
47	if ( a < b) {	47	if ( a < b) {
48	*remainder = a;	48	*remainder = a;
49	return 0;	49	return 0;
50	}	50	}
51		51
52	for ( ; steps > 0; steps--) {	52	for ( ; steps > 0; steps--) {
53	/* shift one bit to remainder */	53	/* shift one bit to remainder */
54	remainder = ( (remainder) << 1) \| (( divident >> 31) & 0x1);	54	remainder = ( (remainder) << 1) \| (( a >> 31) & 0x1);
55	result <<= 1;	55	result <<= 1;
56		56
57	if (*remainder >= b) {	57	if (*remainder >= b) {
58	*remainder -= b;	58	*remainder -= b;
59	result \|= 0x1;	59	result \|= 0x1;
60	}	60	}
61	divident <<= 1;	61	a <<= 1;
62	}	62	}
63		63
64	return result;	64	return result;
65	}	65	}
66		66
67		67
68	static unsigned long divandmod64(unsigned long a, unsigned long b, unsigned long *remainder)	68	static unsigned long divandmod64(unsigned long a, unsigned long b, unsigned long *remainder)
69	{	69	{
70	unsigned long result;	70	unsigned long result;
71	int steps = sizeof(unsigned long);	71	int steps = sizeof(unsigned long) * 8;
72		72
73	*remainder = 0;	73	*remainder = 0;
74	result = 0;	74	result = 0;
75		75
76	if (b == 0) {	76	if (b == 0) {
77	/* FIXME: division by zero */	77	/* FIXME: division by zero */
78	return 0;	78	return 0;
79	}	79	}
80		80
81	if ( a < b) {	81	if ( a < b) {
82	*remainder = a;	82	*remainder = a;
83	return 0;	83	return 0;
84	}	84	}
85		85
86	for ( ; steps > 0; steps--) {	86	for ( ; steps > 0; steps--) {
87	/* shift one bit to remainder */	87	/* shift one bit to remainder */
88	remainder = ( (remainder) << 1) \| (( divident >> 63) & 0x1);	88	remainder = ( (remainder) << 1) \| ((a >> 63) & 0x1);
89	result <<= 1;	89	result <<= 1;
90		90
91	if (*remainder >= b) {	91	if (*remainder >= b) {
92	*remainder -= b;	92	*remainder -= b;
93	result \|= 0x1;	93	result \|= 0x1;
94	}	94	}
95	divident <<= 1;	95	a <<= 1;
96	}	96	}
97		97
98	return result;	98	return result;
99	}	99	}
100		100
101	/* 32bit integer division */	101	/* 32bit integer division */
102	int __divsi3(int a, int b)	102	int __divsi3(int a, int b)
103	{	103	{
104	unsigned int rem;	104	unsigned int rem;
105	int result;	105	int result;
106		106
107	result = (int)divandmod32(ABSVAL(a), ABSVAL(b), &rem);	107	result = (int)divandmod32(ABSVAL(a), ABSVAL(b), &rem);
108		108
109	if ( SGN(a) == SGN(b)) return result;	109	if ( SGN(a) == SGN(b)) return result;
110	return -result;	110	return -result;
111	}	111	}
112		112
113	/* 64bit integer division */	113	/* 64bit integer division */
114	long __divdi3(long a, long b)	114	long __divdi3(long a, long b)
115	{	115	{
116	unsigned long rem;	116	unsigned long rem;
117	long result;	117	long result;
118		118
119	result = (long)divandmod64(ABSVAL(a), ABSVAL(b), &rem);	119	result = (long)divandmod64(ABSVAL(a), ABSVAL(b), &rem);
120		120
121	if ( SGN(a) == SGN(b)) return result;	121	if ( SGN(a) == SGN(b)) return result;
122	return -result;	122	return -result;
123	}	123	}
124		124
125	/* 32bit unsigned integer division */	125	/* 32bit unsigned integer division */
126	unsigned int __udivsi3(unsigned int a, unsigned int b)	126	unsigned int __udivsi3(unsigned int a, unsigned int b)
127	{	127	{
128	unsigned int rem;	128	unsigned int rem;
129	return divandmod32(a, b, &rem);	129	return divandmod32(a, b, &rem);
130	}	130	}
131		131
132	/* 64bit unsigned integer division */	132	/* 64bit unsigned integer division */
133	unsigned long __udivdi3(unsigned long a, unsigned long b)	133	unsigned long __udivdi3(unsigned long a, unsigned long b)
134	{	134	{
135	unsigned long rem;	135	unsigned long rem;
136	return divandmod64(a, b, &rem);	136	return divandmod64(a, b, &rem);
137	}	137	}
138		138
139	/* 32bit remainder of the signed division */	139	/* 32bit remainder of the signed division */
140	int __modsi3(int a, int b)	140	int __modsi3(int a, int b)
141	{	141	{
142	unsigned int rem;	142	unsigned int rem;
143	divandmod32(a, b, &rem);	143	divandmod32(a, b, &rem);
144		144
145	/* if divident is negative, remainder must be too*/	145	/* if divident is negative, remainder must be too */
146	if (!(SGN(a))) {	146	if (!(SGN(a))) {
147	return -((int)rem);	147	return -((int)rem);
148	}	148	}
149		149
150	return (int)rem;	150	return (int)rem;
151	}	151	}
152		152
153	/* 64bit remainder of the signed division */	153	/* 64bit remainder of the signed division */
154	long __moddi3(long a, long b)	154	long __moddi3(long a, long b)
155	{	155	{
156	unsigned long rem;	156	unsigned long rem;
157	divandmod64(a, b, &rem);	157	divandmod64(a, b, &rem);
158		158
159	/* if divident is negative, remainder must be too*/	159	/* if divident is negative, remainder must be too */
160	if (!(SGN(a))) {	160	if (!(SGN(a))) {
161	return -((long)rem);	161	return -((long)rem);
162	}	162	}
163		163
164	return (long)rem;	164	return (long)rem;
165	}	165	}
166		166
167	/* 32bit remainder of the unsigned division */	167	/* 32bit remainder of the unsigned division */
168	unsigned int __umodsi3(unsigned int a, unsigned int b)	168	unsigned int __umodsi3(unsigned int a, unsigned int b)
169	{	169	{
170	unsigned int rem;	170	unsigned int rem;
171	divandmod32(a, b, &rem);	171	divandmod32(a, b, &rem);
172	return rem;	172	return rem;
173	}	173	}
174		174
175	/* 64bit remainder of the unsigned division */	175	/* 64bit remainder of the unsigned division */
176	unsigned long __umoddi3(unsigned long a, unsigned long b)	176	unsigned long __umoddi3(unsigned long a, unsigned long b)
177	{	177	{
178	unsigned long rem;	178	unsigned long rem;
179	divandmod64(a, b, &rem);	179	divandmod64(a, b, &rem);
180	return rem;	180	return rem;
181	}	181	}
182		182
183	unsigned long __udivmoddi3(unsigned long a, unsigned long b, unsigned long *c)	183	unsigned long __udivmoddi3(unsigned long a, unsigned long b, unsigned long *c)
184	{	184	{
185	return divandmod64(a, b, c);	185	return divandmod64(a, b, c);
186	}	186	}
187		187
188		188
189		189

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/genarch/src/softint/division.c – Rev 810 → 811