[net.micro.mac] A quick question regarding a _Control call in assembly code

espen@well.UUCP (Peter Espen) (10/24/86)

	I am examining some assembly code that makes does the following...

   204F           ' O'             MOVEA.L A7,A0
   42A8 000C      'B...'           CLR.L   ioCompletion(A0)
   317C FFFD 0018 '1|....'         MOVE    #-3,ioCRefNum(A0)
   317C 0006 001A '1|....'         MOVE    #6,CSCode(A0)
   217C 0002 FFFD '!|....'         MOVE.L  #$2FFFD,CSParam(A0)
   42A8 0020      'B.. '           CLR.L   CSParam+4(A0)
   42A8 0024      'B..$'           CLR.L   CSParam+8(A0)
   A004           '..'             _Control ; (A0|IOPB:ParmBlkPtr):D0\OSErr 

	I cannot find in any of my documantation a description of what a 
_control call with CScode set to 6 does. Can someone out there give me
some help and tell me what this call does?
		Thanks!
		Peter Espen (espen@well)

brian@ut-sally.UUCP (Brian H. Powell) (10/24/86)

In article <1970@well.UUCP>, espen@well.UUCP (Peter Espen) writes:
> 	I cannot find in any of my documantation a description of what a 
> _control call with CScode set to 6 does.

     This is probably driver-dependant, and you don't say what kind of program
you're looking at, so it's hard to infer.  The disk driver, for example, uses a
CSCode of 6 as an instruction to erase the disk.  I don't think that's what
your piece of code was doing, because the CSParam field was not filled in
correctly.  (The disk driver wanted an integer in CSParam.)

Brian H. Powell
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