:orphan:

========
trace.py
========

SYNOPSIS
========
``trace.py`` [options] FILE [OUTFILE...]

DESCRIPTION
===========
``trace.py`` simulates the execution of machine code in a 48K, 128K or +2 SNA,
SZX or Z80 snapshot, or a binary (raw memory) file. If FILE is '48', '128' or
'+2', no snapshot is loaded, and the RAM is left blank (all zeroes). If
'OUTFILE' is given, an SZX/Z80 snapshot, WAV file or PNG file is written after
execution has completed.

OPTIONS
=======
--audio
  Show a list of the delays (in T-states) between changes in the state of the
  ZX Spectrum speaker made by the code that was executed.

--ay
  Capture AY audio (when writing a WAV file).

--ay-mode `MODE`
  Set the AY stereo mode to ABC, ACB or MONO (the default).

--ay-res `T`
  Set the AY sampling resolution to this many T-states. The default value of
  622 is equivalent to 5700Hz, which is usually good enough for capturing AY
  speech. A higher value such as 70908 (50Hz) is usually good enough for
  capturing AY music, and may also require less time to produce the WAV file.

--beeper
  Capture beeper audio (when used with ``--ay``).

-c, --cmio
  Simulate memory and I/O contention delays and the MEMPTR register.

--depth `N`
  Simplify audio delays to this depth (default: 2). When this option is given,
  any sequence of delays up to length `N` that repeats is shown in a simplified
  form. For example, if `N` is 3, the run of delay values [1, 2, 3, 1, 2, 3] is
  reduced to [1, 2, 3]*2.

-D, --decimal
  Show decimal values in verbose (``-v``, ``-vv``) mode.

-I, --ini `param=value`
  Set the value of a configuration parameter (see ``CONFIGURATION``),
  overriding any value found in ``skoolkit.ini``. This option may be used
  multiple times.

--map FILE
  Log addresses of executed instructions to a file.

-m, --max-operations `MAX`
  Maximum number of instructions to execute. Overrides the `STOP` address (if
  given).

-M, --max-tstates `MAX`
  Maximum number of (simulated) T-states to run for. Overrides the `STOP`
  address (if given).

-n, --no-interrupts
  Don't execute interrupt routines.

-o, --org `ORG`
  Specify the origin address of a binary (raw memory) file. The default origin
  address is 65536 minus the length of the file. `ORG` must be a decimal
  number, or a hexadecimal number prefixed by '0x'.

-p, --poke `[p:]a[-b[-c]],[^+]v`
  POKE N,v in RAM bank p for N in {a, a+c, a+2c..., b} before execution begins.
  Prefix 'v' with '^' to perform an XOR operation, or '+' to perform an ADD
  operation. This option may be used multiple times. 'a', 'b', 'c' and 'v' must
  each be a decimal number, or a hexadecimal number prefixed by '0x'.

--python
  Use the pure Python Z80 simulator even if the C version is available.

-r, --reg `name=value`
  Set the value of a register before execution begins. Do ``--reg help`` for
  more information, or see the section on ``REGISTERS`` below. This option may
  be used multiple times.

--rom `FILE`
  Patch in a ROM at address 0 from this file.

--show-config
  Show configuration parameter values.

-s, --start `ADDR`
  Start execution at this address. `ADDR` must be a decimal number, or a
  hexadecimal number prefixed by '0x'. If this option is omitted, execution
  starts either at the address given by the value of the program counter (for a
  SNA, SZX or Z80 snapshot), or at the origin address of the raw memory file.

-S, --stop `ADDR`
  Stop execution at this address. `ADDR` must be a decimal number, or a
  hexadecimal number prefixed by '0x'.

--screen
  Display screen contents and respond to keypresses while running (requires
  pygame). The left shift key is mapped to CAPS SHIFT on the Spectrum keyboard,
  and the left Ctrl key is mapped to SYMBOL SHIFT.

--state name=value
  Set a hardware state attribute before execution begins. Do ``--state help``
  for more information, or see the section on ``HARDWARE STATE`` below. This
  option may be used multiple times.

--stats
  Show statistics after execution.

-v, --verbose
  Show executed instructions. Repeat this option (``-vv``) to show register
  values too.

-V, --version
  Show SkoolKit version number and exit.

--volume `VOL`
  Set audio volume percentage (default: 100).

REGISTERS
=========
The ``--reg`` option sets the value of a register before execution begins.

|
|  ``--reg name=value``

For example:

|
|  ``--reg hl=32768``
|  ``--reg b=0x1f``

To set the value of an alternate (shadow) register, use the '^' prefix:

|
|  ``--reg ^hl=10072``

Recognised register names are:

|
|  ``^a``, ``^b``, ``^bc``, ``^c``, ``^d``, ``^de``, ``^e``, ``^f``, ``^h``, ``^hl``, ``^l``,
|  ``a``, ``b``, ``bc``, ``c``, ``d``, ``de``, ``e``, ``f``, ``h``, ``hl``, ``l``,
|  ``i``, ``ix``, ``iy``, ``memptr``, ``pc``, ``r``, ``sp``

HARDWARE STATE
==============
The ``--state`` option sets a hardware state attribute before execution begins.

|
|  ``--state name=value``

Recognised attribute names and their default values are:

|
|  ``7ffd``    - last OUT to port 0x7ffd (128K only)
|  ``ay[N]``   - contents of AY register N (N=0-15; 128K only)
|  ``border``  - border colour
|  ``fe``      - last OUT to port 0xfe (SZX only)
|  ``fffd``    - last OUT to port 0xfffd (128K only)
|  ``iff``     - interrupt flip-flop: 0=disabled, 1=enabled
|  ``im``      - interrupt mode
|  ``tstates`` - T-states elapsed since start of frame

CONFIGURATION
=============
``trace.py`` will read configuration from a file named ``skoolkit.ini`` in the
current working directory or in ``~/.skoolkit``, if present. The recognised
configuration parameters are:

  :PNGScale: The PNG image scale factor (default: ``2``).
  :Screen: Display screen contents while running (``1``), or don't (``0``, the
    default).
  :ScreenFps: Screen refresh rate in frames per second (default:``50``). If set
    to 0, ``trace.py`` runs at maximum speed.
  :ScreenScale: Screen scale factor (default: ``2``).
  :TraceHeader: The header to print when ``-v`` is used (default: None).
  :TraceHeader2: The header to print when ``-vv`` is used (default: None).
  :TraceLine: The format of each instruction line when ``-v`` is used
    (default: ``${pc:04X} {i}``).
  :TraceLine2: The format of each instruction line when ``-vv`` is used. Use
    ``--show-config`` to see the default value.
  :TraceLineDecimal: The format of each instruction line when ``-Dv`` is used
    (default: ``{pc:05} {i}``).
  :TraceLineDecimal2: The format of each instruction line when ``-Dvv`` is
    used. Use ``--show-config`` to see the default value.
  :TraceOperand: The prefix, byte format, and word format for the numeric
    operands of instructions, separated by commas (default: ``$,02X,04X``); the
    byte and word formats are standard Python format specifiers for numeric
    values, and default to empty strings if not supplied.
  :TraceOperandDecimal: As ``TraceOperand`` when ``-D`` is used (default:
    ``,,``).

The ``TraceLine*`` parameters are standard Python format strings that recognise
the following replacement fields:

|
|  ``i`` - the current instruction
|  ``m[address]`` - the contents of a memory address
|  ``pc`` - the address of the current instruction (program counter)
|  ``r[X]`` - the 'X' register (see below)
|  ``t`` - the current timestamp (in T-states)

When using the ``m`` (memory) replacement field, ``address`` must be either a
decimal number, or a hexadecimal number prefixed by '$' or '0x'.

The register name ``X`` in ``r[X]`` must be one of the following::

  a b c d e f h l bc de hl
  ^a ^b ^c ^d ^e ^f ^h ^l ^bc ^de ^hl
  ix iy ixh iyh ixl iyl
  i r sp memptr

The names that begin with ``^`` denote the shadow registers.

Wherever ``\n`` appears in a ``TraceLine*`` parameter value, it is replaced by
a newline character.

Configuration parameters must appear in a ``[trace]`` section. For example,
to make ``trace.py`` write a timestamp for each instruction when ``-v`` is
used, add the following section to ``skoolkit.ini``::

  [trace]
  TraceLine={t:>10} ${pc:04X} {i}

Configuration parameters may also be set on the command line by using the
``--ini`` option. Parameter values set this way will override any found in
``skoolkit.ini``.

EXAMPLES
========
1. Execute and show instructions in the routine at 32768-32798 in ``game.z80``:

|
|   ``trace.py -v -s 32768 -S 32798 game.z80``

2. Show delays between changes in the state of the ZX Spectrum speaker produced
   by the sound effect routine at 49152-49193 in ``game.z80``:

|
|   ``trace.py --audio -s 49152 -S 49193 game.z80``
