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pc: add cat() function

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This commit is contained in:
aiju 2016-09-01 10:55:12 +00:00
parent d552fed385
commit 30c9e34c0d
2 changed files with 34 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 cat(a0,n0,...,aN,nN)
Truncate each of the \fIa\fR arguments to \fIn\fR bits and concatenate their binary representation.
.TP
.I gcd(n,m)
The greatest common divisor of \fIn\fR and \fIm\fR.
.TP

31
sys/src/cmd/pc.y
View file

@ -836,6 +836,36 @@ fnrev(int, Num **a)
return a[0];
}
Num *
fncat(int n, Num **a)
{
int i, w;
Num *r;
if(n % 2 != 0){
error("cat: odd number of arguments");
i = 0;
fail:
for(; i < n; i++)
numdecref(a[i]);
return nil;
}
r = numalloc();
for(i = 0; i < n; i += 2){
if(toint(a[i+1], &w, 1)) goto fail;
mpleft(r, w, r);
if(a[i]->sign < 0 || mpsignif(a[i]) > w){
a[i] = nummod(a[i]);
mptrunc(a[i], w, a[i]);
}
r->b = basemax(r->b, a[i]->b);
mpor(r, a[i], r);
numdecref(a[i]);
numdecref(a[i+1]);
}
return r;
}
void
main(int argc, char **argv)
{
@ -863,6 +893,7 @@ main(int argc, char **argv)
regfunc("minv", fnminv, 2);
regfunc("rand", fnrand, 1);
regfunc("rev", fnrev, 2);
regfunc("cat", fncat, -1);
prompt = 1;
ARGBEGIN{