***************************************************************
*                                                             *
*      Module Name: wnotbusy.lib         Rev. 1.00            *
*      Function: Wait for busy flag      Last rev. 06 May 85  *
*                to go down.             By: glh/w6bsk        *
*                                                             *
***************************************************************

* This routine has two entry points: 
     UNBUSY loops until the BUSY flag goes up, then enters
     WTBUSY which loops until the BUSY flag is lowered.

cmdreg    equ  0fce3h    ; Morrow DJ 1791 command port

unbusy:   
          lda  cmdreg    ; Load the status byte and
          ani  0001h     ; mask for busy flag
          jz   unbusy    ; and loop until BUSY flag comes up.
wtbusy:
          lda  cmdreg    ; Load it again and test for the
          ani  0001h     ; BUSY flag to go down.
          jnz  wtbusy
          ret