projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 051b1e55 DF |
1 | /* |
| 2 | * Copyright (c) 1980 Regents of the University of California. | |
| 3 | * All rights reserved. The Berkeley software License Agreement | |
| 4 | * specifies the terms and conditions for redistribution. | |
| 5 | */ | |
| 6 | ||
| 7 | #ifndef lint | |
| 8 | static char sccsid[] = "@(#)madd.c 5.1 (Berkeley) %G%"; | |
| 9 | #endif not lint | |
| 7bd4c8d6 SL |
10 | |
| 11 | #include <mp.h> | |
| 12 | m_add(a,b,c) struct mint *a,*b,*c; | |
| 13 | { int carry,i; | |
| 14 | int x; | |
| 15 | short *cval; | |
| 16 | cval=xalloc(a->len+1,"m_add"); | |
| 17 | carry=0; | |
| 18 | for(i=0;i<b->len;i++) | |
| 19 | { x=carry+a->val[i]+b->val[i]; | |
| 20 | if(x&0100000) | |
| 21 | { carry=1; | |
| 22 | cval[i]=x&077777; | |
| 23 | } | |
| 24 | else | |
| 25 | { carry=0; | |
| 26 | cval[i]=x; | |
| 27 | } | |
| 28 | } | |
| 29 | for(;i<a->len;i++) | |
| 30 | { x=carry+a->val[i]; | |
| 31 | if(x&0100000) cval[i]=x&077777; | |
| 32 | else | |
| 33 | { carry=0; | |
| 34 | cval[i]=x; | |
| 35 | } | |
| 36 | ||
| 37 | } | |
| 38 | if(carry==1) | |
| 39 | { cval[i]=1; | |
| 40 | c->len=i+1; | |
| 41 | } | |
| 42 | else c->len=a->len; | |
| 43 | c->val=cval; | |
| 44 | if(c->len==0) shfree(cval); | |
| 45 | return; | |
| 46 | } | |
| 47 | madd(a,b,c) struct mint *a,*b,*c; | |
| 48 | { struct mint x,y,z; | |
| 49 | int sign; | |
| 50 | x.len=a->len; | |
| 51 | x.val=a->val; | |
| 52 | y.len=b->len; | |
| 53 | y.val=b->val; | |
| 54 | z.len=0; | |
| 55 | sign=1; | |
| 56 | if(x.len>=0) | |
| 57 | if(y.len>=0) | |
| 58 | if(x.len>=y.len) m_add(&x,&y,&z); | |
| 59 | else m_add(&y,&x,&z); | |
| 60 | else | |
| 61 | { y.len= -y.len; | |
| 62 | msub(&x,&y,&z); | |
| 63 | } | |
| 64 | else if(y.len<=0) | |
| 65 | { x.len = -x.len; | |
| 66 | y.len= -y.len; | |
| 67 | sign= -1; | |
| 68 | madd(&x,&y,&z); | |
| 69 | } | |
| 70 | else | |
| 71 | { x.len= -x.len; | |
| 72 | msub(&y,&x,&z); | |
| 73 | } | |
| 74 | xfree(c); | |
| 75 | c->val=z.val; | |
| 76 | c->len=sign*z.len; | |
| 77 | return; | |
| 78 | } | |
| 79 | m_sub(a,b,c) struct mint *a,*b,*c; | |
| 80 | { int x,i; | |
| 81 | int borrow; | |
| 82 | short one; | |
| 83 | struct mint mone; | |
| 84 | one=1; mone.len= 1; mone.val= &one; | |
| 85 | c->val=xalloc(a->len,"m_sub"); | |
| 86 | borrow=0; | |
| 87 | for(i=0;i<b->len;i++) | |
| 88 | { x=borrow+a->val[i]-b->val[i]; | |
| 89 | if(x&0100000) | |
| 90 | { borrow= -1; | |
| 91 | c->val[i]=x&077777; | |
| 92 | } | |
| 93 | else | |
| 94 | { borrow=0; | |
| 95 | c->val[i]=x; | |
| 96 | } | |
| 97 | } | |
| 98 | for(;i<a->len;i++) | |
| 99 | { x=borrow+a->val[i]; | |
| 100 | if(x&0100000) c->val[i]=x&077777; | |
| 101 | else | |
| 102 | { borrow=0; | |
| 103 | c->val[i]=x; | |
| 104 | } | |
| 105 | } | |
| 106 | if(borrow<0) | |
| 107 | { for(i=0;i<a->len;i++) c->val[i] ^= 077777; | |
| 108 | c->len=a->len; | |
| 109 | madd(c,&mone,c); | |
| 110 | } | |
| 111 | for(i=a->len-1;i>=0;--i) if(c->val[i]>0) | |
| 112 | { if(borrow==0) c->len=i+1; | |
| 113 | else c->len= -i-1; | |
| 114 | return; | |
| 115 | } | |
| 116 | shfree(c->val); | |
| 117 | return; | |
| 118 | } | |
| 119 | msub(a,b,c) struct mint *a,*b,*c; | |
| 120 | { struct mint x,y,z; | |
| 121 | int sign; | |
| 122 | x.len=a->len; | |
| 123 | y.len=b->len; | |
| 124 | x.val=a->val; | |
| 125 | y.val=b->val; | |
| 126 | z.len=0; | |
| 127 | sign=1; | |
| 128 | if(x.len>=0) | |
| 129 | if(y.len>=0) | |
| 130 | if(x.len>=y.len) m_sub(&x,&y,&z); | |
| 131 | else | |
| 132 | { sign= -1; | |
| 133 | msub(&y,&x,&z); | |
| 134 | } | |
| 135 | else | |
| 136 | { y.len= -y.len; | |
| 137 | madd(&x,&y,&z); | |
| 138 | } | |
| 139 | else if(y.len<=0) | |
| 140 | { sign= -1; | |
| 141 | x.len= -x.len; | |
| 142 | y.len= -y.len; | |
| 143 | msub(&y,&x,&z); | |
| 144 | } | |
| 145 | else | |
| 146 | { x.len= -x.len; | |
| 147 | madd(&x,&y,&z); | |
| 148 | sign= -1; | |
| 149 | } | |
| 150 | if(a==c && x.len!=0) xfree(a); | |
| 151 | else if(b==c && y.len!=0) xfree(b); | |
| 152 | else xfree(c); | |
| 153 | c->val=z.val; | |
| 154 | c->len=sign*z.len; | |
| 155 | return; | |
| 156 | } |