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pc(1): add nsa() command

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This commit is contained in:
aiju 2016-09-15 08:51:59 +00:00
parent 7bcbef11eb
commit 07284c41f6
2 changed files with 26 additions and 0 deletions
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3
sys/man/1/pc
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@ -93,6 +93,9 @@ The minimum number of bits required to represent \fIn\fR as an unsigned number.
.I sbits(n)
The minimum number of bits required to represent \fIn\fR as an signed number.
.TP
.I nsa(n)
The number of bits set in \fIn\fR.
.TP
.I cat(a\d\s70\s0\u,n\d\s70\s0\u,...,a\d\s7N\s0\u,n\d\s7N\s0\u)
Truncate each of the \fIa\d\s7i\s0\u\fR arguments to \fIn\d\s7i\s0\u\fR bits and concatenate their binary representation.
.TP

23
sys/src/cmd/pc.y
View file

@ -766,6 +766,28 @@ fnsbits(int, Num **a)
return a[0];
}
Num *
fnnsa(int, Num **a)
{
int n, i;
mpdigit d;
a[0] = nummod(a[0]);
if(a[0]->sign < 0){
numdecref(a[0]);
return error("invalid argument");
}
n = 0;
for(i = 0; i < a[0]->top; i++){
d = a[0]->p[i];
for(; d != 0; d &= d-1)
n++;
}
itomp(n, a[0]);
a[0]->b = 0;
return a[0];
}
Num *
fngcd(int, Num **a)
{
@ -889,6 +911,7 @@ main(int argc, char **argv)
regfunc("xtend", fnxtend, 2);
regfunc("ubits", fnubits, 1);
regfunc("sbits", fnsbits, 1);
regfunc("nsa", fnnsa, 1);
regfunc("gcd", fngcd, 2);
regfunc("minv", fnminv, 2);
regfunc("rand", fnrand, 1);