4.3BSD - /usr/src/sys/mdec/mttoggle.s

   1: /*
   2:  * Copyright (c) 1980, 1986 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: _sccsid:.asciz  "@(#)mttoggle.s	7.1 (Berkeley) 6/5/86"
   9: #endif not lint
  10: 
  11: /*
  12:  * Prototype toggle in bootstrap code for mt type tapes.
  13:  * If on anything but a 780 with a tape at drive 0 of mba 1
  14:  * this will have to be repaired by patching mba and mt.
  15:  */
  16:         movl    mba,r10
  17:         mull3   mt,$0x80,r11
  18:         addl3   r11,r10,r11
  19:         addl2   $0x400,r11
  20:         movzbl  $1,4(r10)
  21:         movzbl  $4,8(r11)               /* drive zero, one record */
  22:         clrl    12(r10)                 /* set address to zero */
  23:         movl    $0x80000000,0x800(r10)  /* validate map register */
  24:         cvtwl   $-512,16(r10)           /* set byte count */
  25:         movzwl  $512,20(r11)            /* set byte count */
  26: 0:
  27:         movl    0x44(r11),r0
  28:         bbc     $15,r0,0b
  29:         movzbl  $071,(r11)              /* read forward, go */
  30:         halt
  31:         .align  2
  32: mba:    .long   0x20012000
  33: mt:     .long   0

Defined functions