usr/src/standalone/TEboot.s

#  Stand-alone code to boot TE16 mag tape - read in
#    1st block from tape to core loc 0 and halt
        .set    MBA1,0x20012000
        .set    M_var,MBA1+12  #  MBA 1 virt addr reg
        .set    M_bc,MBA1+16  #  MBA 1 byte count reg
        .set    M_map,MBA1+0x800  #  MBA 1 1st map reg
        .set    M_cr,MBA1+4  #  MBA 1 control reg
        .set    MBAinit,1  #  MBA init bit
#
        .set    TM02,MBA1+0x400  #  TM02 reg's are 1st set of
#                       external reg's on MBA 1
        .set    TM_cs1,TM02+0  #  TM02 control reg
        .set    TM_tc,TM02+36  #  TM02 tape control reg
        .set    TM_fc,TM02+0x14
#
        .set    GO,1  #  go bit
        .set    REDF,070  # read fwd function code
        .set    TCHAR,011700  #  drive 0, odd parity, PDP11,
#                               800 BPI  NRZI, abort on error - for
#                               tape control reg
#
#
        movl    $MBAinit,*$M_cr  #  initialize MBA
        movl    $TCHAR,*$TM_tc  #  set drive characteristics
        clrl    *$M_var  #  virt addr reg = map reg no. + byte offset
        movl    $0x80000000,*$M_map  #  map reg = valid bit + mem page no.
        movl    $-512,*$M_bc  #  byte count = 512
        movl    $REDF+GO,*$TM_cs1  #  read 1 block
        halt