shithub: riscv

Info  •  Files  •  Log  •  Branches

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

--- a/sys/man/1/pc

+++ b/sys/man/1/pc

@@ -89,6 +89,15 @@

 .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.

--- a/sys/src/cmd/pc.y

+++ b/sys/src/cmd/pc.y

@@ -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 @@

 		}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 %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 @@

 	}

 	a[0] = nummod(a[0]);

 	itomp(mpsignif(a[0]), a[0]);

-	a[0]->b = 10;

+	a[0]->b = 0;

 	return a[0];

 }

@@ -762,12 +762,48 @@

 	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 @@

 	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{