Apparently-To: john.smith@gravis.com


GUS Programmer's Digest     Fri, 15 Oct 93  0:07 MDT     Volume 5: Issue  12  

Today's Topics:
                      Two SDK documentation bugs

Standard Info:
	- Meta-info about the GUS can be found at the end of the Digest.
	- Before you ask a question, please READ THE FAQ.

----------------------------------------------------------------------

Date: Thu, 14 Oct 1993 10:19:48 -0400
From: davidm@marcam.com (David MacMahon)
Subject: Two SDK documentation bugs

Hi,

Last night I noticed a couple of bugs in the SDK documentation.  One bug is 
an error in the return value of UltraRecordDmaBusy().  The other is an 
omission in the appendix that deals with the recording control bits that get 
passed to functions like UltraRecordData().

The documentation says that UltraRecordDmaBusy() returns ULTRA_OK (which is 
1) for "No error" or DMA_BUSY (which is 6) if the DMA channel is busy.  A 
quick look in SAMPLE.C will show that this function returns the DMA flags 
ANDed with DMA_PENDING (which is 2); thus the only possible return values 
are 0 (DMA channel NOT busy) and 2 (DMA channel busy).

In the appendix that deals with the recording control bits that get passed 
to functions like UltraRecordData(), the documentation only talks about bit 
1 being used for selecting mono or stereo.  If you look in DMA.C at 
UltraStartRecordDma(), you will see that there is another bit that gets used 
(bit 7) to select whether or not the MSB of each sample is inverted.  Bit 7 
== 0 means signed (two's complement) recording, bit 7 == 1 means unsigned 
recording.

(Sorry, I don't have page numbers handy.)

Gravis/Forte, if these portions of the current SDK documentation are going 
to be "block copied" into the new SDK documentation, please correct these 
bugs when doing so.  (Thanks!)

Hope this helps,
Dave

David MacMahon
Systems Administrator
davidm@marcam.com  <---New address, use this one
davidm@opl.com     <---Old address, don't use this one

------------------------------

End of GUS Programmer's Digest V5 #12
*************************************

To post to tomorrow's digest:               <gus-sdk%itchy@dsd.es.com>
To (un)subscribe or get help:       <gus-sdk-request%itchy@dsd.es.com>
To contact a human (last resort):     <gus-sdk-owner%itchy@dsd.es.com>

FTP sites:         archive.epas.utoronto.ca         pub/pc/ultrasound
                   wuarchive.wustl.edu       systems/msdos/ultrasound
Hints:
      - Get the FAQ from the FTP sites or the request server.
      - Mail to <gus-sdk-request%itchy@dsd.es.com> for info about
	other GUS related mailing lists (UNIX, OS/2, GUS-MIDI, etc.)



