***************************************************************
*                                                             *
*      Module Name: SETTRACK.LIB         Rev. 1.00            *
*      Function: Set a given track       Last rev. 06 May 85  *
*         number into the 1791 port      By: glh/w6bsk        *
*                                                             *
***************************************************************


trkreg    equ  0e3fdh    ; Morrow DJ2B track register

settrk:
          mov  c,a       ; Enter with track # in acc
          sui  30h       ; Force binary, if not already
          cpi  77        ; Test for legal range.
maxtrk    equ  $-1       ; Set in proper max track #+1
          jnc  trkerr
          cpi  00h
          jc   trkerr    ; Negatives not allowed
          sta  curtrk    ; Make it current track
          call notbsy    ; Make sure 1791 is idle
          lda  curtrk
          sta  trkreg    ; and load track register
          adi  30h       ; Make it ascii for possible
          sta  asctrk    ; use elsewhere. 
          ret
trkerr:
          call ccrlf
          call spmsg     
          db   ' Track number not acceptable.',0
          xra  a         ; Set z flag
          ret

curtrk    db   1         ; CMDREG is part of SELCTDRV.LIB
asctrk    db   1