tap2sna.py¶
SYNOPSIS¶
tap2sna.py
[options] INPUT snapshot.z80tap2sna.py
@FILE [args]DESCRIPTION¶
tap2sna.py
converts a TAP or TZX file (which may be inside a zip archive)
into a Z80 snapshot. INPUT may be the full URL to a remote zip archive or
TAP/TZX file, or the path to a local file. Arguments may be read from FILE
instead of (or as well as) being given on the command line.
OPTIONS¶
- -c, –sim-load-config name=value
Set the value of a
--sim-load
configuration parameter. Do-c help
for more information, and see the section onSIMULATED LOAD
below. This option may be used multiple times.- -d, –output-dir DIR
Write the snapshot file in this directory.
- -f, --force
Overwrite an existing snapshot.
- -p, –stack STACK
Set the stack pointer. This option is equivalent to
--reg sp=STACK
. STACK must be a decimal number, or a hexadecimal number prefixed by ‘0x’.
- --ram OPERATION
Perform a load operation or otherwise modify the memory snapshot being built. Do
--ram help
for more information, or see the sections on theCALL
,LOAD
,MOVE
,POKE
andSYSVARS
operations below. This option may be used multiple times.
- –reg name=value
Set the value of a register. Do
--reg help
for more information, or see the section onREGISTERS
below. This option may be used multiple times.- -s, –start START
Set the start address to JP to. This option is equivalent to
--reg pc=START
. START must be a decimal number, or a hexadecimal number prefixed by ‘0x’.
- --sim-load
Simulate a 48K ZX Spectrum running LOAD “”. See the section on
SIMULATED LOAD
below.
- –state name=value
Set a hardware state attribute. Do
--state help
for more information, or see the section onHARDWARE STATE
below. This option may be used multiple times.
- --tape-name NAME
Specify the name of a TAP/TZX file in a zip archive. By default, the first TAP/TZX file found in the zip archive is selected.
- --tape-start BLOCK
Start the tape at this block number. In a TAP/TZX file, the first block is number 1, the second is 2, etc.
- --tape-stop BLOCK
Stop the tape at this block number. In a TAP/TZX file, the first block is number 1, the second is 2, etc.
- --tape-sum MD5SUM
Specify the MD5 checksum of the TAP/TZX file.
tap2sna.py
will abort if there is a checksum mismatch.
- -u, –user-agent AGENT
Set the User-Agent header used in an HTTP(S) request.
- -V, --version
Show the SkoolKit version number and exit.
TZX SUPPORT¶
tap2sna.py
can read data from TZX block types 0x10 (standard speed data),
0x11 (turbo speed data) and 0x14 (pure data), but not block types 0x15 (direct
recording), 0x18 (CSW recording) or 0x19 (generalized data block).
SIMULATED LOAD¶
The --sim-load
option simulates a freshly booted 48K ZX Spectrum running
LOAD “” (or LOAD “”CODE, if the first block on the tape is a ‘Bytes’ header).
Whenever the Spectrum ROM’s load routine at $0556 is called, a shortcut is
taken by “fast loading” the next block on the tape. All other code (including
any custom loader) is fully simulated. Simulation continues until the program
counter hits the start address given by the --start
option, or 10 minutes
of simulated Z80 CPU time has elapsed, or the end of the tape is reached and
one of the following conditions is satisfied:
a custom loader was detected
the program counter hits an address outside the ROM
more than one second of simulated Z80 CPU time has elapsed since the end of the tape was reached
A simulated LOAD can also be aborted by pressing Ctrl-C. When a simulated LOAD has completed or been aborted, the values of the registers (including the program counter) in the simulator are used to populate the Z80 snapshot.
A simulated LOAD can be configured via parameters that are set by the
by the --sim-load-config
(or -c
) option. The recognised configuration
parameters are:
accelerator
- the tape-sampling loop accelerator to use (default: automatically selected - see below); use this to specify a particular accelerator (which may produce a faster simulated LOAD), or to disable acceleration entirely (accelerator=none
)fast-load
- enable fast loading (1
, the default), or disable it (0
); fast loading significantly reduces the load time for many tapes, but can also cause some loaders to failfirst-edge
- the time (in T-states) from the start of the tape at which to place the leading edge of the first pulse (default:-2168
); the default value places the trailing edge of the first pulse at time 0, but some loaders (e.g. polarity-sensitive loaders) requirefirst-edge=0
pause
- pause the tape between blocks and resume playback when port 254 is read (1
, the default), or run the tape continuously (0
); pausing can help with tapes that require (but do not actually contain) long pauses between blocks, but can cause some loaders to failtimeout
- the number of seconds of Z80 CPU time after which to abort the simulated LOAD if it’s still in progress (default: 900)trace
- the file to which to log all instructions executed during the simulated LOAD (default: none)
The names of the available tape-sampling loop accelerators are:
alkatraz
- Alkatrazalkatraz2
- Alkatraz 2bleepload
- Firebird BleepLoadcyberlode
- Cyberlode 1.1digital-integration
- Digital Integrationdinaload
- Dinaloadedge
- Edgeelite-uni-loader
- Elite Uni-Loaderexcelerator
- The Excelerator Loaderflash-loader
- Flash Loaderftl
- FTLgargoyle
- Gargoylegremlin
- various games published by Gremlin Graphicshewson-slowload
- Hewson Slowloadinjectaload
- Injectaloadmicrosphere
- Back to Skool, Skool Daze, Sky Rangernone
- no acceleratorpaul-owens
- Paul Owens Protection Systempoliload
- Poliloadpower-load
- Power-Loadrom
- any loader whose sampling loop is the same as the ROM’ssearch-loader
- Search Loadersoftlock
- SoftLockspeedlock
- Speedlock (all versions)zydroload
- ZydroloadCALL OPERATIONS¶
The --ram
option can be used to call a Python function to perform arbitrary
modification of the memory snapshot.
--ram call=[/path/to/moduledir:]module.function
The function is called with the memory snapshot (a list of 65536 byte values) as the sole positional argument. The function must modify the snapshot in place. The path to the module’s location may be omitted if the module is already in the module search path.
For example:
--ram call=:ram.modify
# Call modify(snapshot) in ./ram.pyLOAD OPERATIONS¶
By default, tap2sna.py
loads bytes from every data block on the tape, using
the start address given in the corresponding header. For tapes that contain
headerless data blocks, headers with incorrect start addresses, or irrelevant
blocks, the --ram
option can be used to load bytes from specific blocks at
the appropriate addresses. The syntax is:
--ram load=[+]block[+],start[,length,step,offset,inc]
where the parameters have the following meanings:
block
The tape block number; the first block is 1, the next is 2, etc. Attach a ‘+’ prefix to load the first byte of the block (which is usually the flag byte), and a ‘+’ suffix to load the last byte (which is usually the parity byte).
start
The destination address at which to start loading.
length
The number of bytes to load (optional; defaults to the number of bytes remaining in the block).
step
This number is added to the destination address after each byte is loaded (optional; default=1).
offset
This number is added to the destination address before a byte is loaded, and subtracted after the byte is loaded (optional; default=0). It is analogous to the offset
d
in theLD (IX+d),L
operation that is commonly used in load routines to copy the byte just loaded from tape (L
) into memory.inc
After
step
is added to the destination address, this number is added too if the result overflowed past 65535 (optional; default=0).
A single tape block can be loaded in two or more stages; for example:
--ram load=2,32768,2048
# Load the first 2K at 32768--ram load=2,0xC000
# Load the remainder at 49152MOVE OPERATIONS¶
The --ram
option can be used to move a block of bytes from one location to
another before saving the snapshot.
--ram move=src,N,dest
This moves a block of N
bytes from src
to dest
. For example:
--ram move=32512,256,32768
# Move 32512-32767 to 32768-33023--ram move=0x9c00,0x100,0x9d00
# Move 39936-40191 to 40192-40447POKE OPERATIONS¶
The --ram
option can be used to POKE values into the snapshot before saving
it.
--ram poke=A[-B[-C]],[^+]V
This does POKE N,V
for N
in {A, A+C, A+2C..., B}
, where:
A
is the first address to POKE
B
is the last address to POKE (optional; default is A
)
C
is the step (optional; default=1)
V
is the value to POKE; prefix the value with ‘^’ to perform an XOR
operation, or ‘+’ to perform an ADD operation
For example:
--ram poke=0x6000,0x10
# POKE 24576,16--ram poke=30000-30002,^85
# Perform ‘XOR 85’ on addresses 30000-30002--ram poke=40000-40004-2,1
# POKE 40000,1: POKE 40002,1: POKE 40004,1SYSVARS OPERATION¶
The --ram
option can be used to initialise the system variables at
23552-23754 (5C00-5CCA) with values suitable for a 48K ZX Spectrum.
--ram sysvars
REGISTERS¶
The --reg
option sets the value of a register in the snapshot.
--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
, pc
, r
, sp
The default value for each register is 0, with the following exceptions:
i=63
iy=23610
HARDWARE STATE¶
The --state
option sets a hardware state attribute.
--state name=value
Recognised attribute names and their default values are:
border
- border colour (default=0)iff
- interrupt flip-flop: 0=disabled, 1=enabled (default=1)im
- interrupt mode (default=1)tstates
- T-states elapsed since start of frame (default=0)READING ARGUMENTS FROM A FILE¶
For complex snapshots that require many --ram
, --reg
or --state
options to build, it may be more convenient to store the arguments to
tap2sna.py
in a file. For example, if the file game.t2s
has the
following contents:
then:
tap2sna.py @game.t2s
will create game.z80
as if the arguments specified in game.t2s
had been
given on the command line.
EXAMPLES¶
Extract the TAP or TZX file from a remote zip archive and convert it into a Z80 snapshot:
tap2sna.py ftp://example.com/game.zip game.z80
Extract the TAP or TZX file from a zip archive, and convert it into a Z80 snapshot with the program counter set to 32768:
tap2sna.py --reg pc=32768 game.zip game.z80
Convert a TZX file into a Z80 snapshot by loading the third block on the tape at 25000:
tap2sna.py --ram load=3,25000 game.tzx game.z80
Convert a TZX file into a Z80 snapshot using options read from the file
game.t2s
:tap2sna.py @game.t2s game.tzx game.z80