QDOS Internals

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This trap sends a byte to a channel.

Call ParametersReturn Parameters
D0.B$05D0.LError code.
D1.BByte to send. D1.LCorrupted.
D3.WTimeout D3.LPreserved.
A0.LChannel ID. A0.LPreserved.


ERR_NCNot complete.
ERR_NOChannel not open.
ERR_DFDrive full.
ERR_OROut of range.


  • All registers not shown above are not used on entry and are preserved on exit.


The example below shows the use of this trap call to send LF to a file. It is assumed that the channel ID is in A0.

Prt_LF  moveq   #10,d1          ; LF
        moveq   #-1,d3          ; Timeout
        moveq   #IO_SBYTE,d0    ; $05
        trap    #3              ; Send the byte.
        tst.l   d0              ; OK? . .
        bne     error ---->     ; . . no!
qdosmsq/traps/trap_3/sbyt.txt · Last modified: 2009/03/02 16:47 by george.gwilt