1 files changed, 92 insertions, 0 deletions

diff --git a/2019/day5/intcode.pl b/2019/day5/intcode.pl
new file mode 100644
index 0000000..613f067
--- /dev/null
+++ b/2019/day5/intcode.pl
@@ -0,0 +1,92 @@
+use strict;
+use warnings;
+use Data::Dumper;
+# use Smart::Comments;
+use v5.10;
+
+sub pos {
+    my ($tape_ref, $index) = @_;
+    my @tape = @{ $tape_ref };
+    ### returning: $tape[$tape[$index]]
+    ### for: $index
+    return $tape[$tape[$index]];
+}
+
+sub imm {
+    my ($tape_ref, $index) = @_;
+    my @tape = @{ $tape_ref };
+    return $tape[$index];
+}
+
+my $inputline = <STDIN>;
+chomp $inputline;
+my @tape = split /,/,  $inputline;
+
+my $pc = 0; # program counter is no longer consistent
+
+my @actions = (
+    sub { print "noop" },                 # no opcode 0
+    sub { return $_[0] + $_[1] },         # 1
+    sub { return $_[0] * $_[1] },         # 2
+    sub { return 5; },                    # 3
+    sub { say $_[0]; },                   # 4
+    sub { return $_[0] ? $_[1] : -1 },    # 5, ugh, you might want to jump to 0
+    sub { return $_[0] ? -1 : $_[1] },    # 6
+    sub { return $_[0] < $_[1] ? 1 : 0},  # 7
+    sub { return $_[0] == $_[1] ? 1 : 0}, # 8
+);
+
+my @modes = (\&pos, \&imm);
+my %offsets = qw/1 4 2 4 3 2 4 2 5 3 6 3 7 4 8 4 99 1/;
+my $inst_ptr = 0;
+
+while ( 1 ) {
+
+    my $raw_op_code = $tape[$inst_ptr];
+    last if ($raw_op_code == 99);
+
+    # print("====================================\n");
+
+    my @modes_and_opcode;
+    push @modes_and_opcode, $_ // 0 for $raw_op_code =~ m/^(\d)??(\d)??(\d)??0?(\d)$/g;
+    ### @modes_and_opcode
+
+    my $op_code = pop @modes_and_opcode;
+    ### $op_code
+
+    # foreach my $x (0..5) {
+    #     print("TAPE[" . ($inst_ptr + $x) . "] = $tape[($inst_ptr + $x)]\n")
+    # }
+
+    my $toread = $offsets{$op_code} - 1; # excluding opcode
+    my @params;
+    foreach my $offset (1..$toread) {
+        push @params, $modes[ (!($op_code == 4 || $op_code == 5 || $op_code == 6) && $offset == $toread) ? 1 : pop @modes_and_opcode ]->(\@tape, $inst_ptr + $offset);
+    }
+    ### @params
+
+    $inst_ptr += $offsets{$op_code};
+
+    if ($op_code == 1 || $op_code == 2 || $op_code == 7 || $op_code == 8) { # arithmetic
+        my $res = $actions[$op_code]->($params[0], $params[1]);
+        $tape[$params[2]] = $res;
+        ### writing: $res
+        ### on address: $params[2]
+    }
+    elsif ($op_code == 3) { # input
+        my $res = $actions[$op_code]->();
+        $tape[$params[0]] = $res;
+        ### saved: $res
+        ### on: $params[0]
+    } elsif ($op_code == 4) { # output
+        $actions[$op_code]->($params[0]);
+    } elsif ($op_code == 5 || $op_code == 6) { # jumps
+        my $res = $actions[$op_code]->($params[0], $params[1]);
+        $inst_ptr = $res == -1 ? $inst_ptr : $res;
+        ### jumped to: $inst_ptr
+        next;
+    } else {
+        ### OH NO...
+        die;
+    }
+}