Commit | Line | Data |
---|---|---|
7bd4c8d6 SL |
1 | /* @(#)madd.c 4.1 %G% */ |
2 | ||
3 | #include <mp.h> | |
4 | m_add(a,b,c) struct mint *a,*b,*c; | |
5 | { int carry,i; | |
6 | int x; | |
7 | short *cval; | |
8 | cval=xalloc(a->len+1,"m_add"); | |
9 | carry=0; | |
10 | for(i=0;i<b->len;i++) | |
11 | { x=carry+a->val[i]+b->val[i]; | |
12 | if(x&0100000) | |
13 | { carry=1; | |
14 | cval[i]=x&077777; | |
15 | } | |
16 | else | |
17 | { carry=0; | |
18 | cval[i]=x; | |
19 | } | |
20 | } | |
21 | for(;i<a->len;i++) | |
22 | { x=carry+a->val[i]; | |
23 | if(x&0100000) cval[i]=x&077777; | |
24 | else | |
25 | { carry=0; | |
26 | cval[i]=x; | |
27 | } | |
28 | ||
29 | } | |
30 | if(carry==1) | |
31 | { cval[i]=1; | |
32 | c->len=i+1; | |
33 | } | |
34 | else c->len=a->len; | |
35 | c->val=cval; | |
36 | if(c->len==0) shfree(cval); | |
37 | return; | |
38 | } | |
39 | madd(a,b,c) struct mint *a,*b,*c; | |
40 | { struct mint x,y,z; | |
41 | int sign; | |
42 | x.len=a->len; | |
43 | x.val=a->val; | |
44 | y.len=b->len; | |
45 | y.val=b->val; | |
46 | z.len=0; | |
47 | sign=1; | |
48 | if(x.len>=0) | |
49 | if(y.len>=0) | |
50 | if(x.len>=y.len) m_add(&x,&y,&z); | |
51 | else m_add(&y,&x,&z); | |
52 | else | |
53 | { y.len= -y.len; | |
54 | msub(&x,&y,&z); | |
55 | } | |
56 | else if(y.len<=0) | |
57 | { x.len = -x.len; | |
58 | y.len= -y.len; | |
59 | sign= -1; | |
60 | madd(&x,&y,&z); | |
61 | } | |
62 | else | |
63 | { x.len= -x.len; | |
64 | msub(&y,&x,&z); | |
65 | } | |
66 | xfree(c); | |
67 | c->val=z.val; | |
68 | c->len=sign*z.len; | |
69 | return; | |
70 | } | |
71 | m_sub(a,b,c) struct mint *a,*b,*c; | |
72 | { int x,i; | |
73 | int borrow; | |
74 | short one; | |
75 | struct mint mone; | |
76 | one=1; mone.len= 1; mone.val= &one; | |
77 | c->val=xalloc(a->len,"m_sub"); | |
78 | borrow=0; | |
79 | for(i=0;i<b->len;i++) | |
80 | { x=borrow+a->val[i]-b->val[i]; | |
81 | if(x&0100000) | |
82 | { borrow= -1; | |
83 | c->val[i]=x&077777; | |
84 | } | |
85 | else | |
86 | { borrow=0; | |
87 | c->val[i]=x; | |
88 | } | |
89 | } | |
90 | for(;i<a->len;i++) | |
91 | { x=borrow+a->val[i]; | |
92 | if(x&0100000) c->val[i]=x&077777; | |
93 | else | |
94 | { borrow=0; | |
95 | c->val[i]=x; | |
96 | } | |
97 | } | |
98 | if(borrow<0) | |
99 | { for(i=0;i<a->len;i++) c->val[i] ^= 077777; | |
100 | c->len=a->len; | |
101 | madd(c,&mone,c); | |
102 | } | |
103 | for(i=a->len-1;i>=0;--i) if(c->val[i]>0) | |
104 | { if(borrow==0) c->len=i+1; | |
105 | else c->len= -i-1; | |
106 | return; | |
107 | } | |
108 | shfree(c->val); | |
109 | return; | |
110 | } | |
111 | msub(a,b,c) struct mint *a,*b,*c; | |
112 | { struct mint x,y,z; | |
113 | int sign; | |
114 | x.len=a->len; | |
115 | y.len=b->len; | |
116 | x.val=a->val; | |
117 | y.val=b->val; | |
118 | z.len=0; | |
119 | sign=1; | |
120 | if(x.len>=0) | |
121 | if(y.len>=0) | |
122 | if(x.len>=y.len) m_sub(&x,&y,&z); | |
123 | else | |
124 | { sign= -1; | |
125 | msub(&y,&x,&z); | |
126 | } | |
127 | else | |
128 | { y.len= -y.len; | |
129 | madd(&x,&y,&z); | |
130 | } | |
131 | else if(y.len<=0) | |
132 | { sign= -1; | |
133 | x.len= -x.len; | |
134 | y.len= -y.len; | |
135 | msub(&y,&x,&z); | |
136 | } | |
137 | else | |
138 | { x.len= -x.len; | |
139 | madd(&x,&y,&z); | |
140 | sign= -1; | |
141 | } | |
142 | if(a==c && x.len!=0) xfree(a); | |
143 | else if(b==c && y.len!=0) xfree(b); | |
144 | else xfree(c); | |
145 | c->val=z.val; | |
146 | c->len=sign*z.len; | |
147 | return; | |
148 | } |