2019 day 9 init from day 7

2019/day09/README.org

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+** --- Day 9: Sensor Boost ---
+You've just said goodbye to the rebooted rover and left Mars when you
+receive a faint distress signal coming from the asteroid belt. It must
+be the Ceres monitoring station!
+
+In order to lock on to the signal, you'll need to boost your sensors.
+The Elves send up the latest /BOOST/ program - Basic Operation Of System
+Test.
+
+While BOOST (your puzzle input) is capable of boosting your sensors, for
+tenuous safety reasons, it refuses to do so until the computer it runs
+on passes some checks to demonstrate it is a /complete Intcode
+computer/.
+
+[[file:5][Your existing Intcode computer]] is missing one key feature:
+it needs support for parameters in /relative mode/.
+
+Parameters in mode =2=, /relative mode/, behave very similarly to
+parameters in /position mode/: the parameter is interpreted as a
+position. Like position mode, parameters in relative mode can be read
+from or written to.
+
+The important difference is that relative mode parameters don't count
+from address =0=. Instead, they count from a value called the /relative
+base/. The /relative base/ starts at =0=.
+
+The address a relative mode parameter refers to is itself /plus/ the
+current /relative base/. When the relative base is =0=, relative mode
+parameters and position mode parameters with the same value refer to the
+same address.
+
+For example, given a relative base of =50=, a relative mode parameter of
+=-7= refers to memory address =50 + -7 = 43=.
+
+The relative base is modified with the /relative base offset/
+instruction:
+
+- Opcode =9= /adjusts the relative base/ by the value of its only
+  parameter. The relative base increases (or decreases, if the value is
+  negative) by the value of the parameter.
+
+For example, if the relative base is =2000=, then after the instruction
+=109,19=, the relative base would be =2019=. If the next instruction
+were =204,-34=, then the value at address =1985= would be output.
+
+Your Intcode computer will also need a few other capabilities:
+
+- The computer's available memory should be much larger than the initial
+  program. Memory beyond the initial program starts with the value =0=
+  and can be read or written like any other memory. (It is invalid to
+  try to access memory at a negative address, though.)
+- The computer should have support for large numbers. Some instructions
+  near the beginning of the BOOST program will verify this capability.
+
+Here are some example programs that use these features:
+
+- =109,1,204,-1,1001,100,1,100,1008,100,16,101,1006,101,0,99= takes no
+  input and produces a
+  [[https://en.wikipedia.org/wiki/Quine_(computing)][copy of itself]] as
+  output.
+- =1102,34915192,34915192,7,4,7,99,0= should output a 16-digit number.
+- =104,1125899906842624,99= should output the large number in the
+  middle.
+
+The BOOST program will ask for a single input; run it in test mode by
+providing it the value =1=. It will perform a series of checks on each
+opcode, output any opcodes (and the associated parameter modes) that
+seem to be functioning incorrectly, and finally output a BOOST keycode.
+
+Once your Intcode computer is fully functional, the BOOST program should
+report no malfunctioning opcodes when run in test mode; it should only
+output a single value, the BOOST keycode. /What BOOST keycode does it
+produce?/
+
+To begin, [[file:9/input][get your puzzle input]].
+
+Answer:
+
+You can also [Shareon
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