Commit | Line | Data |
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168f834f PW |
1 | #include <mp.h> |
2 | mdiv(a,b,q,r) MINT *a,*b,*q,*r; | |
3 | { MINT x,y; | |
4 | int sign; | |
5 | sign=1; | |
6 | x.val=a->val; | |
7 | y.val=b->val; | |
8 | x.len=a->len; | |
9 | if(x.len<0) {sign= -1; x.len= -x.len;} | |
10 | y.len=b->len; | |
11 | if(y.len<0) {sign= -sign; y.len= -y.len;} | |
12 | xfree(q); | |
13 | xfree(r); | |
14 | m_div(&x,&y,q,r); | |
15 | if(sign==-1) | |
16 | { q->len= -q->len; | |
17 | r->len = - r->len; | |
18 | } | |
19 | return; | |
20 | } | |
21 | m_dsb(q,n,a,b) short *a,*b; | |
22 | { long int x,qx; | |
23 | int borrow,j,u; | |
24 | qx=q; | |
25 | borrow=0; | |
26 | for(j=0;j<n;j++) | |
27 | { x=borrow-a[j]*qx+b[j]; | |
28 | b[j]=x&077777; | |
29 | borrow=x>>15; | |
30 | } | |
31 | x=borrow+b[j]; | |
32 | b[j]=x&077777; | |
33 | if(x>>15 ==0) { return(0);} | |
34 | borrow=0; | |
35 | for(j=0;j<n;j++) | |
36 | { u=a[j]+b[j]+borrow; | |
37 | if(u<0) borrow=1; | |
38 | else borrow=0; | |
39 | b[j]=u&077777; | |
40 | } | |
41 | { return(1);} | |
42 | } | |
43 | m_trq(v1,v2,u1,u2,u3) | |
44 | { long int d; | |
45 | long int x1; | |
46 | if(u1==v1) d=077777; | |
47 | else d=(u1*0100000L+u2)/v1; | |
48 | while(1) | |
49 | { x1=u1*0100000L+u2-v1*d; | |
50 | x1=x1*0100000L+u3-v2*d; | |
51 | if(x1<0) d=d-1; | |
52 | else {return(d);} | |
53 | } | |
54 | } | |
55 | m_div(a,b,q,r) MINT *a,*b,*q,*r; | |
56 | { MINT u,v,x,w; | |
57 | short d,*qval; | |
58 | int qq,n,v1,v2,j; | |
59 | u.len=v.len=x.len=w.len=0; | |
60 | if(b->len==0) { fatal("mdiv divide by zero"); return;} | |
61 | if(b->len==1) | |
62 | { r->val=xalloc(1,"m_div1"); | |
63 | sdiv(a,b->val[0],q,r->val); | |
64 | if(r->val[0]==0) | |
65 | { shfree(r->val); | |
66 | r->len=0; | |
67 | } | |
68 | else r->len=1; | |
69 | return; | |
70 | } | |
71 | if(a->len < b->len) | |
72 | { q->len=0; | |
73 | r->len=a->len; | |
74 | r->val=xalloc(r->len,"m_div2"); | |
75 | for(qq=0;qq<r->len;qq++) r->val[qq]=a->val[qq]; | |
76 | return; | |
77 | } | |
78 | x.len=1; | |
79 | x.val = &d; | |
80 | n=b->len; | |
81 | d=0100000L/(b->val[n-1]+1L); | |
82 | mult(a,&x,&u); /*subtle: relies on fact that mult allocates extra space */ | |
83 | mult(b,&x,&v); | |
84 | v1=v.val[n-1]; | |
85 | v2=v.val[n-2]; | |
86 | qval=xalloc(a->len-n+1,"m_div3"); | |
87 | for(j=a->len-n;j>=0;j--) | |
88 | { qq=m_trq(v1,v2,u.val[j+n],u.val[j+n-1],u.val[j+n-2]); | |
89 | if(m_dsb(qq,n,v.val,&(u.val[j]))) qq -= 1; | |
90 | qval[j]=qq; | |
91 | } | |
92 | x.len=n; | |
93 | x.val=u.val; | |
94 | mcan(&x); | |
95 | sdiv(&x,d,&w,(short *)&qq); | |
96 | r->len=w.len; | |
97 | r->val=w.val; | |
98 | q->val=qval; | |
99 | qq=a->len-n+1; | |
100 | if(qq>0 && qval[qq-1]==0) qq -= 1; | |
101 | q->len=qq; | |
102 | if(qq==0) shfree(qval); | |
103 | if(x.len!=0) xfree(&u); | |
104 | xfree(&v); | |
105 | return; | |
106 | } |