xref: /plan9/sys/src/cmd/unix/drawterm/include/mp.h (revision 8ccd4a6360d974db7bd7bbd4f37e7018419ea908)
1 #define _MPINT 1
2 
3 // the code assumes mpdigit to be at least an int
4 // mpdigit must be an atomic type.  mpdigit is defined
5 // in the architecture specific u.h
6 
7 typedef struct mpint mpint;
8 
9 struct mpint
10 {
11 	int	sign;	// +1 or -1
12 	int	size;	// allocated digits
13 	int	top;	// significant digits
14 	mpdigit	*p;
15 	char	flags;
16 };
17 
18 enum
19 {
20 	MPstatic=	0x01,
21 	Dbytes=		sizeof(mpdigit),	// bytes per digit
22 	Dbits=		Dbytes*8		// bits per digit
23 };
24 
25 // allocation
26 void	mpsetminbits(int n);	// newly created mpint's get at least n bits
27 mpint*	mpnew(int n);		// create a new mpint with at least n bits
28 void	mpfree(mpint *b);
29 void	mpbits(mpint *b, int n);	// ensure that b has at least n bits
30 void	mpnorm(mpint *b);		// dump leading zeros
31 mpint*	mpcopy(mpint *b);
32 void	mpassign(mpint *old, mpint *new);
33 
34 // random bits
35 mpint*	mprand(int bits, void (*gen)(uchar*, int), mpint *b);
36 
37 // conversion
38 mpint*	strtomp(char*, char**, int, mpint*);	// ascii
39 int	mpfmt(Fmt*);
40 char*	mptoa(mpint*, int, char*, int);
41 mpint*	letomp(uchar*, uint, mpint*);	// byte array, little-endian
42 int	mptole(mpint*, uchar*, uint, uchar**);
43 mpint*	betomp(uchar*, uint, mpint*);	// byte array, little-endian
44 int	mptobe(mpint*, uchar*, uint, uchar**);
45 uint	mptoui(mpint*);			// unsigned int
46 mpint*	uitomp(uint, mpint*);
47 int	mptoi(mpint*);			// int
48 mpint*	itomp(int, mpint*);
49 uvlong	mptouv(mpint*);			// unsigned vlong
50 mpint*	uvtomp(uvlong, mpint*);
51 vlong	mptov(mpint*);			// vlong
52 mpint*	vtomp(vlong, mpint*);
53 
54 // divide 2 digits by one
55 void	mpdigdiv(mpdigit *dividend, mpdigit divisor, mpdigit *quotient);
56 
57 // in the following, the result mpint may be
58 // the same as one of the inputs.
59 void	mpadd(mpint *b1, mpint *b2, mpint *sum);	// sum = b1+b2
60 void	mpsub(mpint *b1, mpint *b2, mpint *diff);	// diff = b1-b2
61 void	mpleft(mpint *b, int shift, mpint *res);	// res = b<<shift
62 void	mpright(mpint *b, int shift, mpint *res);	// res = b>>shift
63 void	mpmul(mpint *b1, mpint *b2, mpint *prod);	// prod = b1*b2
64 void	mpexp(mpint *b, mpint *e, mpint *m, mpint *res);	// res = b**e mod m
65 void	mpmod(mpint *b, mpint *m, mpint *remainder);	// remainder = b mod m
66 
67 // quotient = dividend/divisor, remainder = dividend % divisor
68 void	mpdiv(mpint *dividend, mpint *divisor,  mpint *quotient, mpint *remainder);
69 
70 // return neg, 0, pos as b1-b2 is neg, 0, pos
71 int	mpcmp(mpint *b1, mpint *b2);
72 
73 // extended gcd return d, x, and y, s.t. d = gcd(a,b) and ax+by = d
74 void	mpextendedgcd(mpint *a, mpint *b, mpint *d, mpint *x, mpint *y);
75 
76 // res = b**-1 mod m
77 void	mpinvert(mpint *b, mpint *m, mpint *res);
78 
79 // bit counting
80 int	mpsignif(mpint*);	// number of sigificant bits in mantissa
81 int	mplowbits0(mpint*);	// k, where n = 2**k * q for odd q
82 
83 // well known constants
84 extern mpint	*mpzero, *mpone, *mptwo;
85 
86 // sum[0:alen] = a[0:alen-1] + b[0:blen-1]
87 // prereq: alen >= blen, sum has room for alen+1 digits
88 void	mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum);
89 
90 // diff[0:alen-1] = a[0:alen-1] - b[0:blen-1]
91 // prereq: alen >= blen, diff has room for alen digits
92 void	mpvecsub(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *diff);
93 
94 // p[0:n] += m * b[0:n-1]
95 // prereq: p has room for n+1 digits
96 void	mpvecdigmuladd(mpdigit *b, int n, mpdigit m, mpdigit *p);
97 
98 // p[0:n] -= m * b[0:n-1]
99 // prereq: p has room for n+1 digits
100 int	mpvecdigmulsub(mpdigit *b, int n, mpdigit m, mpdigit *p);
101 
102 // p[0:alen*blen-1] = a[0:alen-1] * b[0:blen-1]
103 // prereq: alen >= blen, p has room for m*n digits
104 void	mpvecmul(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *p);
105 
106 // sign of a - b or zero if the same
107 int	mpveccmp(mpdigit *a, int alen, mpdigit *b, int blen);
108 
109 // divide the 2 digit dividend by the one digit divisor and stick in quotient
110 // we assume that the result is one digit - overflow is all 1's
111 void	mpdigdiv(mpdigit *dividend, mpdigit divisor, mpdigit *quotient);
112 
113 // playing with magnitudes
114 int	mpmagcmp(mpint *b1, mpint *b2);
115 void	mpmagadd(mpint *b1, mpint *b2, mpint *sum);	// sum = b1+b2
116 void	mpmagsub(mpint *b1, mpint *b2, mpint *sum);	// sum = b1+b2
117 
118 // chinese remainder theorem
119 typedef struct CRTpre	CRTpre;		// precomputed values for converting
120 					//  twixt residues and mpint
121 typedef struct CRTres	CRTres;		// residue form of an mpint
122 
123 struct CRTres
124 {
125 	int	n;		// number of residues
126 	mpint	*r[1];		// residues
127 };
128 
129 CRTpre*	crtpre(int, mpint**);			// precompute conversion values
130 CRTres*	crtin(CRTpre*, mpint*);			// convert mpint to residues
131 void	crtout(CRTpre*, CRTres*, mpint*);	// convert residues to mpint
132 void	crtprefree(CRTpre*);
133 void	crtresfree(CRTres*);
134 
135