aaru-dps/docs
1
0
Fork 0
mirror of https://github.com/aaru-dps/docs.git synced 2025-12-16 11:14:37 +00:00
Code Issues Packages Projects Releases Wiki Activity
Files
devel
docs/Commodore/SIDPLAY.TXT

511 lines
22 KiB
Plaintext
Raw Permalink Blame History

*** SID/PSID (Various SIDPlay / PlaySID Formats)
*** Document revision: 1.2
*** Last updated: March 15, 2004
*** Compiler/Editor: Peter Schepers
*** Contributors/sources: LaLa,
Peter Weighill
The data files used by SIDPLAY contain binary C64 data and music player
machine code. Both, the programmer on the C64 and this emulator need
information on how to access the code inside the binary file. That means,
information like the memory location to load the file to, the number of
tunes, the starting address of the executable code and its subroutines.
This specific information has to be delivered in either a separate file -
which is often called info file - or in form of a header in the single
binary data file. A standalone C64 data file without a header or without a
corresponding info file is considered invalid.
It is recommended that you get accustomed to one-file sidtunes with the
*.sid extension. For raw C64 binary files the extension .c64 or .prg is
preferred in order to be able to assign a .sid extension to the additional
info file.
Supported and merely used file formats are:
PlaySID single-file-format (widely known as PSID)
PlaySID info-file-format (Raw C64 binary file plus Amiga Workbench icon
tooltype file .INFO)
SIDPLAY info-file-format (Raw C64 binary file plus SIDPLAY ASCII text
info file, previously .SID)
C64 Sidplayer format (.MUS/.STR)
Raw data or PSID files have appeared as *.data, *.psid or psid.*.
DAT files
The .DAT file name extension has been introduced by the early versions of
SIDPLAY/DOS. It has never been used to specify a file format. Its main use
has been in assigning a unique file name extension to any sidtune file, but
especially raw C64 data files, and allowing to use .SID for additional info
files.
INFO files
These are Amiga Workbench tooltype icons containing binary graphics data
and ASCII text information strings. They have been used by PlaySID and are
supported by SIDPLAY. Their file name extension normally is .info or .INF.
This is a two-file format. A separate C64 binary data file is required. On
Amiga the corresponding C64 data files usually haven't had filename
extensions. However, they might have been renamed on other systems.
SIDPLAY info files
These are plain ASCII text files which have been introduced by the
earlier versions of SIDPLAY/DOS. They are used to be able to alter the
information inside with a normal ASCII text editor. They can be converted
to a single file that contains a binary header. This is a two-file format.
A separate C64 binary data file is required. Notice that each pair of files
usually has the old DOS-naming of .SID for the info file and .DAT for the
C64 data file.
The SIDPLAY info file is derived from the information inside the PlaySID
one-file format. It is structured like this:
SIDPLAY INFOFILE
ADDRESS=<loadAddress>,<initAddress>,<playAddress>
SONGS=<total>[,<start>]
SPEED=<hexValue>
NAME=<name of music/tune>
AUTHOR=<name of author/composer>
COPYRIGHT=<year/name of copyright owner/company>
RELEASED=<year/name of copyright owner/company>
SIDSONG=<YES|NO>
RELOC=<hexValue>,<hexValue>
CLOCK=<PAL|NTSC>
SIDMODEL=<6581|8580>
COMPATIBILITY=<R64|BASIC>
The first line of the text containing ``SIDPLAY INFOFILE'' is only used
to identify the type of file.
ADDRESS=<loadAddress>,<initAddress>,<playAddress>
Each specified address is a 16-bit effective C64 memory location in case
insensitive hexa-decimal notation without a prefix, e.g. C000 or E012, but
neither $FCE2 nor 0xFCE2. Preceding zeroes are ignored.
<loadAddress> is the C64 memory location where to put the C64 data. 0
means, the data is in original C64 format, i.e. the first two bytes contain
the little-endian load address (low byte, high byte). Please don't
explicitly specify the load address unless required for sure. If the load
address is explicitly specified, some sidtune converters and utilities
conjecture that the C64 data lacks its load address. Hence they move it in
front of the C64 data. This would create two redundant bytes if the C64
data already had a load address in the first two bytes. Additionally, those
extra bytes in the beginning can confuse disassemblers.
<initAddress> is the start address of the machine code subroutine that
initializes a song by accepting the contents of the 8-bit 6510 Accumulator
as the song number parameter. 0 means, the address is equal to the
effective load address.
<playAddress> is the start address of the machine code subroutine that can
be called frequently to produce a continuous sound. 0 means, the
initialization subroutine is expected to install an interrupt handler,
which then calls the music player. If so, the value in the bank-select
register $01 determines whether the IRQ vector $0314/$0315 (Kernal-ROM on)
or the IRQ vector $FFFE/$FFFF (Kernal-ROM off) is to be used.
SONGS=<total>,[<start>]
<total> is the decimal number of songs (or sound effects) that can be
initialized by calling the init address. The minimum is 1.
<start> is the decimal number of the song to be played by default. This
value is meant as a proposal and is optional. It has a default of 1. It
often specifies the first song you would hear upon starting the program is
has been taken from.
SPEED=<value>
<value> is a value in case insensitive hexa-decimal notation without a
prefix. Preceding zeroes are ignored. The value contains information about
the speed of each song. For each song a bit is reserved, bit 0 for song 1,
bit 1 for song 2, and so on. A bit set to 0 means, the music player
subroutine is called at 50 Hz. A bit set to 1 means, the real speed is
indicated by the CIA 1 Timer A $DC04/05, which defaults to 60 Hz. To not
break compatibility to the PlaySID formats, use a maximum of 32 bits, which
is equal to 32 songs. Due to a bug in PlaySID, the PSID format can only
handle up to 8 songs correctly. On the contrary, the SIDPLAY info format is
extended to 256 bits, which is equal to 256 songs. Examples: SPEED=0
replays every song at 50 Hz speed. SPEED=1F replays songs 1-5 at 60 Hz
speed, all other songs at 50 Hz speed.
NAME=<name of music/tune>
AUTHOR=<name of author/composer>
RELEASED=<year/name of copyright owner/company>
or
COPYRIGHT=<year/name of copyright owner/company>
These three fields are all plain ASCII text strings. There are limited to
a maximum of 80 characters each. To not break compatibility to the PlaySID
formats, use a maximum of 31 characters.
SIDSONG=<YES|NO>
is used to indicate that the corresponding C64 data file is in (Enhanced)
Sidplayer file format. This field is optional and defaults to NO.
RELOC=<hexValue>,<hexValue>
is used to indicate a free memory range not used by the sid tune. (e.g.
RELOC=04,65)
CLOCK=<PAL|NTSC>
is used to indicate the type of C64 the tune was original written for.
SIDMODEL=<6581|8580>
is used to indicate the type of sid chip the tune was original written
for.
COMPATIBILITY=<R64|BASIC>
is used to indicate the compatibility mode of the sid tune. Normally this
would not be included but is set to R64 when the tune includes "sample"
music and will only play correctly on a real c64 or a newer sidplayer. This
is set to BASIC when the .dat file contains BASIC code.
An example file ``EXAMPLE.SID'' may look like this:
SIDPLAY INFOFILE
ADDRESS=2AF0,3002,300C
SONGS=3,2
SPEED=0
NAME=Example
AUTHOR=Example
RELEASED=199? (c) Example
SIDSONG=NO
PSID/RSID file header
The detailed structure of the SID header looks like the following. Header
offsets are in hexadecimal notation. Other integer values are decimal
unless explicitly marked otherwise. Any stored integer values are in
big-endian format:
+00 magicID: ``PSID'' or ``RSID''
This is a four byte long ASCII character string containing the value
0x50534944 or 0x52534944. 'RSID' (Real SID) denotes that the file strictly
requires a true Commodore-64 environment to run properly. 'PSID' files will
generally run trouble-free on older PlaySID and libsidplay1 based
emulators, too.
Some words about the Real C64 SID file format (RSID):
The RSID format was designed to contain tunes that are not PlaySID
compatible, but strictly require a real C64 environment to run. Tunes that
are multi-speed and/or contain samples and/or use additional interrupt
sources or do busy looping will cause older SID emulators to lock up or
play very wrongly (if at all).
By using the name RSID for such rips all existing SID emulators will
reject these tunes safely until they can be upgraded to cope with the
additional requirements.
Due to the nature of these tunes, every effort must be made to make sure
they are directly runnable on an actual C64 computer. As such the tunes
will only be presented with the default C64 power-on environment and
expected to configure and use all hardware appropriately.
RSID is based on PSIDv2NG with the following modifications:
magicID = RSID
version = only 2
loadAddress = 0 (reserved)
playAddress = 0 (reserved)
speed = 0 (reserved)
psidSpecific flag is called C64BASIC flag
The above fields MUST be checked and if any differ from the above then
the tune MUST be rejected. The definitions above will force tunes to
contain proper hardware configuration code and install valid interrupt
handlers.
The default C64 environment is as follows:
VIC - IRQ set to raster 0, but not enabled.
CIA 1 timer A - set to 60Hz with the counter running and IRQs active.
Other timers - disabled and loaded with $FFFF.
Bank register - $37
A side effect of the bank register is that init MUST NOT be located under
a ROM/IO memory area (addesses $0000-$07E8, $A000-$BFFF and $D000-$FFFF).
Since every effort needs to be made to run the tune on a real C64 the load
address of the image MUST NOT be set lower than $07E8.
+04 WORD version
Available version number can either be 0001 or 0002. Headers of version 2
provide additional fields. RSID and PSID v2NG files must have 0002 here.
+06 WORD dataOffset
This is the offset from the start of the file to the C64 binary data
area. Because of the fixed size of the header, this is either 0x0076 for
version 1 and 0x007C for version 2.
+08 WORD loadAddress
The C64 memory location where to put the C64 data. 0 means the data are
in original C64 binary file format, i.e. the first two bytes of the data
contain the little-endian load address (low byte, high byte). This must
always be true for RSID files. Furthermore, the actual load address must
NOT be less than $07E8 in RSID files.
You must be absolutely sure what to enter here. There is no way to detect
automatically whether the first two bytes in a C64 data file are meant to
be a load address or some arbitrary bytes of code or data. Unless your C64
file is not a normal binary file and thus has no load address in front, you
need not enter anything else than 0 here. The SID tune will not play if you
specify a load address which is present in the C64 file already.
Normal C64 binary data files have a load address in their first two
bytes, so they can be loaded to a pre-defined destination address by
executing LOAD"FILE",8,1, for instance. If a load address is explicitly
specified in the sidtune info file, some sidtune converters and utilities
conjecture that the C64 data don't have a load address in their first two
bytes. Hence, the explicit load address from the info file is moved in
front of the C64 data to create a valid C64 binary file which can be easily
loaded on a C64, too. If that C64 file were to be saved, it would contain
two superfluous data bytes at offset 2 if an original load address had been
in the first two bytes of the old file. This process of adding a duplicate
load address can be repeated. The file loader strips off the first two
bytes (the used load address) and puts the rest of the file contents
(including the now obsolete load address at file offset 2) into memory. If
the new load address is the same than the old one the two added bytes cause
the whole data to be displaced by two bytes, which most likely results in
malfunctioning code. Also, superfluous bytes in memory then can confuse
disassemblers which start at the beginning of the file or memory buffer.
+0A WORD initAddress
The start address of the machine code subroutine that initializes a song,
accepting the contents of the 8-bit 6510 Accumulator as the song number
parameter. 0 means the address is equal to the effective load address.
In RSID files initAddress must never point to a ROM area ($A000-$BFFF or
$D000-$FFFF) or be lower than $07E8. Also, if the C64 BASIC flag is set,
initAddress must be 0.
+0C WORD playAddress
The start address of the machine code subroutine that can be called
frequently to produce a continuous sound. 0 means the initialization
subroutine is expected to install an interrupt handler, which then calls
the music player at some place. This must always be true for RSID files.
+0E WORD songs
The number of songs (or sound effects) that can be initialized by calling
the init address. The minimum is 1. The maximum is 256.
+10 WORD startSong
The song number to be played by default. This value is optional. It often
specifies the first song you would hear upon starting the program is has
been taken from. It has a default of 1.
+12 LONGWORD speed
This is a 32 bit big endian number. Each bit in 'speed' specifies the
speed for the corresponding tune number, i.e. bit 0 specifies the speed for
tune 1. If there are more than 32 tunes, the speed specified for tune 32 is
also used for all higher numbered tunes.
A 0 bit specifies vertical blank interrupt (50Hz PAL, 60Hz NTSC), and a 1
bit specifies CIA 1 timer interrupt (default 60Hz).
Surplus bits in 'speed' should be set to 0.
For RSID files 'speed' must always be set to 0.
Note that if 'play' = 0, the bits in 'speed' should still be set for
backwards compatibility with older SID players. New SID players running in
a C64 environment will ignore the speed bits in this case.
WARNING: This field does not work in PlaySID for Amiga like it was
intended, therefore the above is a redefinition of the original 'speed'
field in SID v2NG! See also the 'clock' (video standard) field described
below for 'flags'.
+16 ``<name>''
+36 ``<author>''
+56 ``<released>'' (also known as ``<copyright>'')
These are 32 byte long zero terminated ASCII character strings. Upon
evaluating the header, a zero byte will always be put into the last byte of
each string. So the maximum number of available free characters is 31.
+76 <data>
Version 1 of the SID header is complete at this point. The binary C64
data starts here.
Version 2 of the header incorporates the v1 header fields and provides
additional fields. Some of these are actually v2NG specific - those are
noted below.
+76 WORD flags
This is a 16 bit big endian number containing the following bitfields:
Bit 0 specifies format of the binary data (musPlayer):
0 = built-in music player,
1 = Compute!'s Sidplayer MUS data, music player must be merged.
If this bit is set, the appended binary data are in Compute!'s Sidplayer
MUS format, and does not contain a built-in music player. An external
player machine code must be merged to replay such a sidtune.
Bit 1 specifies whether the tune is PlaySID specific, e.g. uses PlaySID
samples (psidSpecific):
0 = C64 compatible,
1 = PlaySID specific (PSID v2NG)
1 = C64 BASIC flag (RSID)
This is a v2NG and RSID specific field.
PlaySID samples were invented to facilitate playback of C64 volume
register samples with the original Amiga PlaySID software. PlaySID samples
made samples a reality on slow Amiga hardware with a player that was
updated only once a frame.
Unfortunately, converting C64 volume samples to PlaySID samples means
that they can no longer be played on a C64, and furthermore the conversion
might potentially break the non-sample part of a tune if the timing between
writes to the SID registers is at all altered. This follows from the ADSR
bugs in the SID chip.
Today, the speed of common hardware and the sophistication of the SID
players is such that there is little need for PlaySID samples. However,
with all the PlaySID sample PSIDs in existence there's a need to
differentiate between SID files containing only original C64 code and PSID
files containing PlaySID samples or having other PlaySID specific issues.
As stated above, bit 1 in 'flags' is reserved for this purpose.
Since RSID files do not have the need for PlaySID samples, this flag is
used for a different purpose: tunes that include a BASIC executable portion
will be played (with the BASIC portion executed) if the C64 BASIC flag is
set. At the same time, initAddress must be 0.
Bits 2-3 specify the video standard (clock):
00 = Unknown,
01 = PAL,
10 = NTSC,
11 = PAL and NTSC.
This is a v2NG specific field.
As can be seen from the 'speed' field, it is not possible to specify NTSC
C64 playback. This is unfortunate, since the different clock speeds means
that a tune written for the NTSC C64 will be slightly detuned if played
back on a PAL C64. Furthermore, NTSC C64 tunes driven by a vertical blank
interrupt have to be converted to use the CIA 1 timer to fit into this
scheme. This can cause severe problems, as the NTSC refresh rate is once
every 17045 cycles, while the CIA 1 timer A is latched with 17095 cycles.
Apart from the difference in timing itself, the SID ADSR bugs can actually
break the tune.
The 'clock' (video standard) field was introduced to circumvent this
problem.
Bits 4-5 specify the SID version (sidModel):
00 = Unknown,
01 = MOS6581,
10 = MOS8580,
11 = MOS6581 and MOS8580.
This is a v2NG specific field.
The MOS6581 and the MOS8580 have three notable differences. First,
combined waveforms are generally louder on a MOS8580, to the extent that
some combinations that are clearly audible on a MOS8580 are completely
silent on a MOS6581. Second, the internal DC levels in the MOS8580 are so
small that software or hardware tricks must be used to play volume samples.
Third, the MOS8580 analog filter has totally different characteristics from
the MOS6581 analog filter.
To ensure that music specifically written for one of the two SID versions
can be played back correctly, bits 4-5 in 'flags' are used as stated above.
Bits 6-15 are reserved and should be set to 0.
+78 BYTE startPage (relocStartPage)
This is a v2NG specific field.
This is an 8 bit number. If 'startPage' is 0, the SID file is clean, i.e.
it does not write outside its data range within the driver ranges. In this
case the largest free memory range can be determined from the start address
and the data length of the SID binary data. If 'startPage' is 0xFF, there
is not even a single free page, and driver relocation is impossible.
Otherwise, 'startPage' specifies the start page of the single largest free
memory range within the driver ranges. For example, if 'startPage' is 0x1E,
this free memory range starts at $1E00.
+79 BYTE pageLength (relocPages)
This is a v2NG specific field.
This is an 8 bit number indicating the number of free pages after
'startPage'. If 'startPage' is not 0 or 0xFF, 'pageLength' is set to the
number of free pages starting at 'startPage'. If 'startPage' is 0 or 0xFF,
'pageLength' must be set to 0.
The relocation range indicated by 'startPage' and 'pageLength' should
never overlap or encompass the load range of the C64 data. For RSID files,
the relocation range should also not overlap or encompass any of the ROM
areas ($A000-$BFFF and $D000-$FFFF) or the reserved memory area
($0000-$03FF).
+7A WORD reserved
This is a 16 bit number and is reserved and should be set to 0.
+7C <data>
Version 2 of the SID header ends here. This offset is the start of the
binary C64 data. See also 'loadAddress' for what the first 2 bytes of
'data' might indicate.
MUS files
The .MUS & .STR file name extensions are used for Compute's Sidplayer
music files.
The overall file layout is as follows:
The first two bytes contain the load address.
The next two bytes contain the length of the data for Voice 1
The next two bytes contain the length of the data for Voice 2
The next two bytes contain the length of the data for Voice 3
Then the data for Voice 1 follows immediately
Then the data for Voice 2 follows immediately
Then the data for Voice 3 follows immediately
Then the text description of the music file (upto 5 lines)
The data for each Voice consists of a stream of two byte commands and
should be terminated with a HALT code which is 01 4F.
The text description can be upto 5 lines long, each line upto 32
characters wide. It is made up of PETSCII characters and may contain colour
codes. The text description should be terminated with a 00 byte (but might
not be).
Reference in New Issue View Git Blame Copy Permalink