From @masak

<grondilu> nom​: my ($x, $y) = (2**30, 1); printf "%32b\n", +^$x +& $y;
<p6eval> nom acbec8​:
OUTPUT«1111000000000000000000000000000000000000000000000000000000000001␤»
<grondilu> where do those four bits come from??
<grondilu> niecza​: my ($x, $y) = (2**30, 1); printf "%32b", +^$x +& $y;
<p6eval> niecza v13-389-g852f0ff​: OUTPUT« 1»
<moritz> grondilu​: I just realized, libtommath (which we use for
storing bigints) uses 28bit "digits"
<moritz> grondilu​: so there might indeed a bug in there somewhere
<grondilu> oh, this explains a lot
<moritz> grondilu​: feel free to submit as rakudobug (or even fix if you want :-)
<grondilu> I don't know how to. Someone please do it.
* masak submits rakudobug
<moritz> libtommath stores sign separately from the rest of the bits,
which is why we need to emulate 2's complement math
<moritz> and that part might be buggy

From grizzly@smit.id.au

On 04/02/12 00​:54, Carl Mäsak (via RT) wrote​:

# New Ticket Created by "Carl Mäsak"
# Please include the string​: [perl #​109740]
# in the subject line of all future correspondence about this issue.
#<URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=109740>

<grondilu> nom​: my ($x, $y) = (2**30, 1); printf "%32b\n", +^$x +& $y;
what is unary +^ I can only find binary +^ bitwise xor
<p6eval> nom acbec8​:
OUTPUT«1111000000000000000000000000000000000000000000000000000000000001␤»
<grondilu> where do those four bits come from??
<grondilu> niecza​: my ($x, $y) = (2**30, 1); printf "%32b", +^$x +& $y;
<p6eval> niecza v13-389-g852f0ff​: OUTPUT« 1»
<moritz> grondilu​: I just realized, libtommath (which we use for
storing bigints) uses 28bit "digits"
<moritz> grondilu​: so there might indeed a bug in there somewhere
<grondilu> oh, this explains a lot
<moritz> grondilu​: feel free to submit as rakudobug (or even fix if you want :-)
<grondilu> I don't know how to. Someone please do it.
* masak submits rakudobug
<moritz> libtommath stores sign separately from the rest of the bits,
which is why we need to emulate 2's complement math
<moritz> and that part might be buggy

--

  .~. In my life God comes first....
  /V\ but Linux is pretty high after that :-D
  /( )\ Francis (Grizzly) Smit
  ^^-^^ http://www.smit.id.au/

The RT System itself - Status changed from 'new' to 'open'

From @masak

Francis (>)​:

what is unary +^ I can only find binary +^ bitwise xor

See S03​:677. It's numeric bitwise addition.

From @moritz

Fixed, and tested in S03-operators/bit.t.

@moritz - Status changed from 'open' to 'resolved'