rzxplay.py

SYNOPSIS

rzxplay.py [options] FILE [OUTFILE]

DESCRIPTION

rzxplay.py plays an RZX file. If ‘OUTFILE’ is given, an SZX or Z80 snapshot or an RZX file is written after playback has completed.

OPTIONS

--flags FLAGS

Set playback flags. Do --flags help for more information, or see the section on FLAGS below.

--force

Force playback when unsupported hardware is detected.

--fps FPS

Run at this many frames per second (default: 50). 0 means maximum speed.

--map FILE

Log addresses of executed instructions to a file.

--no-screen

Run without a screen.

--python

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

--quiet

Don’t print progress percentage during playback.

--scale SCALE

Scale the display up by this factor (1-4; default: 2).

--snapshot FILE

Specify an external snapshot file to start with.

--stop FRAMES

Stop after playing this many frames.

--trace FILE

Log executed instructions to a file.

-V, --version

Show the SkoolKit version number and exit.

SUPPORTED MACHINES

rzxplay.py can play RZX files that were recorded in 48K, 128K or +2 mode with no peripherals (e.g. Interface 1) attached. The --force option can be used to make rzxplay.py attempt playback of files that were recorded on unsupported machines or with unsupported hardware attached, but they are unlikely to play to the end.

SCREEN

If pygame is installed, rzxplay.py will use it to render the Spectrum’s screen contents at 50 frames per second by default. Use the --fps option to change the frame rate. Specifying --fps 0 makes rzxplay.py run at maximum speed. To disable the screen and make rzxplay.py run even faster, use the --no-screen option.

CODE EXECUTION MAP

The --map option can be used to log the addresses of instructions executed during playback to a file. This file can then be used by sna2ctl.py to produce a control file. If the file specified by the --map option already exists, any addresses it contains will be merged with those of the instructions executed.

FLAGS

The --flags option sets flags that control the playback of RZX frames when interrupts are enabled. If an RZX file fails to play to completion, setting one or more of these flags may help. FLAGS is the sum of the following values, chosen according to the desired outcome:

  • 1 - When the last instruction in a frame is either ‘LD A,I’ or ‘LD A,R’, reset bit 2 of the flags register. This is the expected behaviour of a real Z80, but some RZX files fail when this flag is set.

  • 2 - When the last instruction in a frame is ‘EI’, and the next frame is a short one (i.e. has a fetch count of 1 or 2), block the interrupt in the next frame. By default, and according to RZX convention, rzxplay.py accepts an interrupt at the start of every frame except the first, regardless of whether the instruction just executed would normally block it. However, some RZX files contain a short frame immediately after an ‘EI’ to indicate that the interrupt should in fact be blocked, and therefore require this flag to be set to play back correctly.

OUTPUT FILE

If OUTFILE is given, and ends with either ‘.z80’ or ‘.szx’, then a snapshot in the corresponding format is written when playback ends. Similarly, if OUTFILE ends with ‘.rzx’, then an RZX file is written when playback ends. However, this makes sense only if --stop is used to end playback somewhere in the middle of the input RZX file, otherwise the output RZX file will be empty (i.e. contain no frames).

EXAMPLES

  1. Play game.rzx:


rzxplay.py game.rzx
  1. Log the instructions executed while playing game.rzx:


rzxplay.py --trace game.log game.rzx
  1. Play only 100 frames of game.rzx and then write game-100.rzx:


rzxplay.py --stop 100 game.rzx game-100.rzx