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



/** @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;

    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;

    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;

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;
    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 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 2071	Rev 2505
Line 32...	Line 32...
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,
-		41	unsigned int *remainder)
41	{	42	{
42	unsigned int result;	43	unsigned int result;
43	int steps = sizeof(unsigned int) * 8;	44	int steps = sizeof(unsigned int) * 8;
44		45
45	*remainder = 0;	46	*remainder = 0;
Line 48...	Line 49...
48	if (b == 0) {	49	if (b == 0) {
49	/* FIXME: division by zero */	50	/* FIXME: division by zero */
50	return 0;	51	return 0;
51	}	52	}
52		53
53	if ( a < b) {	54	if (a < b) {
54	*remainder = a;	55	*remainder = a;
55	return 0;	56	return 0;
56	}	57	}
57		58
58	for ( ; steps > 0; steps--) {	59	for (; steps > 0; steps--) {
59	/* shift one bit to remainder */	60	/* shift one bit to remainder */
60	remainder = ( (remainder) << 1) \| (( a >> 31) & 0x1);	61	remainder = ((remainder) << 1) \| (( a >> 31) & 0x1);
61	result <<= 1;	62	result <<= 1;
62		63
63	if (*remainder >= b) {	64	if (*remainder >= b) {
64	*remainder -= b;	65	*remainder -= b;
65	result \|= 0x1;	66	result \|= 0x1;
66	}	67	}
67	a <<= 1;	68	a <<= 1;
68	}	69	}
69		70
70	return result;	71	return result;
71	}	72	}
72		73
73		74
74	static unsigned long long divandmod64(unsigned long long a, unsigned long long b, unsigned long long *remainder)	75	static unsigned long long divandmod64(unsigned long long a,
-		76	unsigned long long b, unsigned long long *remainder)
75	{	77	{
76	unsigned long long result;	78	unsigned long long result;
77	int steps = sizeof(unsigned long long) * 8;	79	int steps = sizeof(unsigned long long) * 8;
78		80
79	*remainder = 0;	81	*remainder = 0;
Line 82...	Line 84...
82	if (b == 0) {	84	if (b == 0) {
83	/* FIXME: division by zero */	85	/* FIXME: division by zero */
84	return 0;	86	return 0;
85	}	87	}
86		88
87	if ( a < b) {	89	if (a < b) {
88	*remainder = a;	90	*remainder = a;
89	return 0;	91	return 0;
90	}	92	}
91		93
92	for ( ; steps > 0; steps--) {	94	for (; steps > 0; steps--) {
93	/* shift one bit to remainder */	95	/* shift one bit to remainder */
94	remainder = ( (remainder) << 1) \| ((a >> 63) & 0x1);	96	remainder = ((remainder) << 1) \| ((a >> 63) & 0x1);
95	result <<= 1;	97	result <<= 1;
96		98
97	if (*remainder >= b) {	99	if (*remainder >= b) {
98	*remainder -= b;	100	*remainder -= b;
99	result \|= 0x1;	101	result \|= 0x1;
100	}	102	}
101	a <<= 1;	103	a <<= 1;
102	}	104	}
103		105
104	return result;	106	return result;
Line 108...	Line 110...
108	int __divsi3(int a, int b)	110	int __divsi3(int a, int b)
109	{	111	{
110	unsigned int rem;	112	unsigned int rem;
111	int result;	113	int result;
112		114
113	result = (int)divandmod32(ABSVAL(a), ABSVAL(b), &rem);	115	result = (int) divandmod32(ABSVAL(a), ABSVAL(b), &rem);
114		116
115	if ( SGN(a) == SGN(b)) return result;	117	if (SGN(a) == SGN(b))
-		118	return result;
116	return -result;	119	return -result;
117	}	120	}
118		121
119	/* 64bit integer division */	122	/* 64bit integer division */
120	long long __divdi3(long long a, long long b)	123	long long __divdi3(long long a, long long b)
121	{	124	{
122	unsigned long long rem;	125	unsigned long long rem;
123	long long result;	126	long long result;
124		127
125	result = (long long)divandmod64(ABSVAL(a), ABSVAL(b), &rem);	128	result = (long long) divandmod64(ABSVAL(a), ABSVAL(b), &rem);
126		129
127	if ( SGN(a) == SGN(b)) return result;	130	if (SGN(a) == SGN(b))
-		131	return result;
128	return -result;	132	return -result;
129	}	133	}
130		134
131	/* 32bit unsigned integer division */	135	/* 32bit unsigned integer division */
132	unsigned int __udivsi3(unsigned int a, unsigned int b)	136	unsigned int __udivsi3(unsigned int a, unsigned int b)
Line 148...	Line 152...
148	unsigned int rem;	152	unsigned int rem;
149	divandmod32(a, b, &rem);	153	divandmod32(a, b, &rem);
150		154
151	/* if divident is negative, remainder must be too */	155	/* if divident is negative, remainder must be too */
152	if (!(SGN(a))) {	156	if (!(SGN(a))) {
153	return -((int)rem);	157	return -((int) rem);
154	}	158	}
155		159
156	return (int)rem;	160	return (int) rem;
157	}	161	}
158		162
159	/* 64bit remainder of the signed division */	163	/* 64bit remainder of the signed division */
160	long long __moddi3(long long a,long long b)	164	long long __moddi3(long long a,long long b)
161	{	165	{
162	unsigned long long rem;	166	unsigned long long rem;
163	divandmod64(a, b, &rem);	167	divandmod64(a, b, &rem);
164		168
165	/* if divident is negative, remainder must be too */	169	/* if divident is negative, remainder must be too */
166	if (!(SGN(a))) {	170	if (!(SGN(a))) {
167	return -((long long)rem);	171	return -((long long) rem);
168	}	172	}
169		173
170	return (long long)rem;	174	return (long long) rem;
171	}	175	}
172		176
173	/* 32bit remainder of the unsigned division */	177	/* 32bit remainder of the unsigned division */
174	unsigned int __umodsi3(unsigned int a, unsigned int b)	178	unsigned int __umodsi3(unsigned int a, unsigned int b)
175	{	179	{
Line 184...	Line 188...
184	unsigned long long rem;	188	unsigned long long rem;
185	divandmod64(a, b, &rem);	189	divandmod64(a, b, &rem);
186	return rem;	190	return rem;
187	}	191	}
188		192
189	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b, unsigned long long *c)	193	unsigned long long __udivmoddi3(unsigned long long a, unsigned long long b,
-		194	unsigned long long *c)
190	{	195	{
191	return divandmod64(a, b, c);	196	return divandmod64(a, b, c);
192	}	197	}
193		198
194	/** @}	199	/** @}

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(root)/trunk/kernel/genarch/src/softint/division.c @ 2093 – Rev 2071 → 2505