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 Subfunction 20 : Play a module

 AH    = 82
 AL    = 20
 DX:CX = Buffer with the following data
 If the function is successful, AX will hold 5722h on return.

 +--------------------------------------------------------------------------+
 | Offset | Length | Description                                            |
 |--------+--------+--------------------------------------------------------|
 |   00   |  Byte  | This byte must be set to 'M'.                          |
 |   01   |  Byte  | This byte must be set to 'P'.                          |
 |   02   |  Byte  | This byte represents the output device. The possible   |
 |        |        | output devices can be determined from the device table |
 |        |        | returned in the test for residency (function 21).      |
 |        |        | For older versions of MODRES which don't support this  |
 |        |        | table, the following values can be assumed:            |
 |        |        |  0 - PC Speaker                                        |
 |        |        |  1 - D/A on LPT1                                       |
 |        |        |  2 - D/A on LPT2                                       |
 |        |        |  3 - D/A on 1&2 (Stereo)                               |
 |        |        |  4 - D/A on 1&2 (Mono)                                 |
 |        |        |  5 - LPT1 on Video Card                                |
 |        |        |  6 - D/A @300/2 (Stereo)                               |
 |        |        |  7 - Sound Blaster (210)                               |
 |        |        |  8 - Sound Blaster (220)                               |
 |        |        |  9 - Sound Blaster (230)                               |
 |        |        |  A - Sound Blaster (240)                               |
 |        |        |  B - Sound Blaster (250)                               |
 |        |        |  C - Sound Blaster (260)                               |
 |        |        |  D - Mono D/A User Def                                 |
 |        |        |  E - Stereo D/A User Def                               |
 |   03   |  Word  | Segment of data area holding the first 5 sections of   |
 |        |        | the MOD file structure. Note that the data area must   |
 |        |        | be paragraph aligned since only the segment is given.  |
 |   05   |   62   | The 31 segment addresses of the sample data for each   |
 |        |        | of the 31 samples (the sample data is the data         |
 |        |        | described in section 6 of the MOD file structure).     |
 |        |        | Note that the data areas must be paragraph aligned     |
 |        |        | since only the segment is given in each case.          |
 |   67   |  Byte  | The pattern number at which to start playing.          |
 |   68   |  Byte  | If this byte is set to 1 only the starting pattern     |
 |        |        | will be played. If this is set to 0, the entire module |
 |        |        | will be played, starting at the specified pattern.     |
 |--------+--------+--------------------------------------------------------|
 |   69   |  Byte  | This byte is used to specify the quality of sound      |
 |        |        | output required. It can have a value in the range 0 to |
 |        |        | 6 - the lower the value, the better the quality. Note, |
 |        |        | however, that you will need a fast machinve to use the |
 |        |        | low values without crashing. A value of 1 is assumed   |
 |        |        | if an out of range value is specified.                 |
 |   70   |  Byte  | If this is set to 80, then the mod contains samples    |
 |        |        | with lengths greater then 64K. If anything else, then  |
 |        |        | all samples must be less than 64K.                     |
 +--------------------------------------------------------------------------+

 Note that bytes 69 and 70 were not available in the old versions of MODRES.