  # DSP 56001 Host Communication

  DSP main page,
  DSP System calls.
  DMA System calls.
  DSP Host Communication Example.
  DMA Handshaked Communication Example.

  This example illustrates a typical DSP Host communication program.

  >     ; DSP Host Port IO
  >     : Author: Fredrik Noring, 1994

  >     M_HSR   EQU     $FFE9        ; Host Status Register
  >     M_HRX   EQU     $FFEB        ; Host Receive Data Register
  >     M_HTX   EQU     $FFEB        ; Host Transmit Data Register

  >               org    p:$0
  >               jmp    <start

  >               org    p:$40
  >     start     jsr    <Host_get   ; Receive Host data
  >               move   #0.27,A     ; Move value to the 56-bits A register
  >               move   #0.31415,y0 ; Move value to the 24-bits y0 register
  >               mac    x0,y0,A     ; Multiply x0 and y0 and accumulate to A
  >               move   A,x0        ; Move the A1 portion of A to x0
  >               jsr    <Host_send  ; Send Host data

  >               jmp    <start      ; Continue

  >     ; Host I/O routines.
  >     Host_get  jclr    #0,X:<<M_HSR,<Host_get
  >               movep   X:<<M_HRX,x0  ; Move 24-bits Host data to x0
  >               rts
  >     Host_send jclr    #1,X:<<M_HSR,<Host_send    ;
  >               movep   x0,X:<<M_HTX  ; Move x0 to 24-bits Host data
  >               rts