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pc: add gcd, rand and minv; set base of logical operation results to 0

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This commit is contained in:
aiju 2016-08-29 09:57:15 +02:00
parent a08bf6831f
commit e95082f66c
2 changed files with 58 additions and 10 deletions
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9
sys/man/1/pc
View file

@ -89,6 +89,15 @@ The minimum number of bits required to represent \fIn\fR as an unsigned number.
.TP
.I sbits(n)
The minimum number of bits required to represent \fIn\fR as an signed number.
.TP
.I gcd(n,m)
The greatest common divisor of \fIn\fR and \fIm\fR.
.TP
.I minv(n,m)
The inverse of \fIn\fR mod \fIm\fR.
.TP
.I rand(n)
A random number satisfying 0 ≤ \fIrand(n)\fR < \fIn\fR.
.SS Control statements
.PP
Control statements are always evaluated with default input base 10.

59
sys/src/cmd/pc.y
View file

@ -4,8 +4,8 @@
#include <bio.h>
#include <ctype.h>
#include <mp.h>
#include <pool.h>
#include <thread.h>
#include <libsec.h>
int inbase = 10, outbase, divmode, sep, fail, prompt;
enum { MAXARGS = 16 };
@ -175,12 +175,12 @@ numbin(int op, Num *a, Num *b)
}else
mpasr(a, mptoi(b), a);
break;
case '<': itomp(mpcmp(a, b) < 0, a); break;
case '>': itomp(mpcmp(a, b) > 0, a); break;
case LOLE: itomp(mpcmp(a, b) <= 0, a); break;
case LOGE: itomp(mpcmp(a, b) >= 0, a); break;
case LOEQ: itomp(mpcmp(a, b) == 0, a); break;
case LONE: itomp(mpcmp(a, b) != 0, a); break;
case '<': itomp(mpcmp(a, b) < 0, a); a->b = 0; break;
case '>': itomp(mpcmp(a, b) > 0, a); a->b = 0; break;
case LOLE: itomp(mpcmp(a, b) <= 0, a); a->b = 0; break;
case LOGE: itomp(mpcmp(a, b) >= 0, a); a->b = 0; break;
case LOEQ: itomp(mpcmp(a, b) == 0, a); a->b = 0; break;
case LONE: itomp(mpcmp(a, b) != 0, a); a->b = 0; break;
case LOLAND:
a->b = b->b;
if(mpcmp(a, mpzero) == 0)
@ -435,7 +435,7 @@ expr: LNUM
| '+' expr %prec unary { $$ = $2; }
| '-' expr %prec unary { $$ = nummod($2); if($$ != nil) mpsub(mpzero, $$, $$); }
| '~' expr %prec unary { $$ = nummod($2); if($$ != nil) mpnot($$, $$); }
| '!' expr %prec unary { $$ = nummod($2); if($$ != nil) itomp(mpcmp($$, mpzero) == 0, $$); }
| '!' expr %prec unary { $$ = nummod($2); if($$ != nil) {itomp(mpcmp($$, mpzero) == 0, $$); $$->b = 0; } }
| expr '?' expr ':' expr %prec '?' {
if($1 == nil || mpcmp($1, mpzero) != 0){
$$ = $3;
@ -752,7 +752,7 @@ fnubits(int, Num **a)
}
a[0] = nummod(a[0]);
itomp(mpsignif(a[0]), a[0]);
a[0]->b = 10;
a[0]->b = 0;
return a[0];
}
@ -762,11 +762,47 @@ fnsbits(int, Num **a)
a[0] = nummod(a[0]);
if(a[0]->sign < 0) mpadd(a[0], mpone, a[0]);
itomp(mpsignif(a[0]) + 1, a[0]);
a[0]->b = 10;
a[0]->b = 0;
return a[0];
}
Num *
fngcd(int, Num **a)
{
a[0] = nummod(a[0]);
a[0]->b = basemax(a[0]->b, a[1]->b);
mpextendedgcd(a[0], a[1], a[0], nil, nil);
return a[0];
}
Num *
fnrand(int, Num **a)
{
Num *n;
n = numalloc();
n->b = a[0]->b;
mpnrand(a[0], genrandom, n);
numdecref(a[0]);
return n;
}
Num *
fnminv(int, Num **a)
{
mpint *x;
a[0] = nummod(a[0]);
x = mpnew(0);
mpextendedgcd(a[0], a[1], x, a[0], nil);
if(mpcmp(x, mpone) != 0)
error("no modular inverse");
else
mpmod(a[0], a[1], a[0]);
mpfree(x);
numdecref(a[1]);
return a[0];
}
void
main(int argc, char **argv)
@ -791,6 +827,9 @@ main(int argc, char **argv)
regfunc("xtend", fnxtend, 2);
regfunc("ubits", fnubits, 1);
regfunc("sbits", fnsbits, 1);
regfunc("gcd", fngcd, 2);
regfunc("minv", fnminv, 2);
regfunc("rand", fnrand, 1);
prompt = 1;
ARGBEGIN{