projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| b1078c35 | 1 | /* |
| 0880b18e | 2 | * Copyright (c) 1980, 1986 Regents of the University of California. |
| b1078c35 KM |
3 | * All rights reserved. The Berkeley software License Agreement |
| 4 | * specifies the terms and conditions for redistribution. | |
| 5 | */ | |
| 6 | ||
| 7 | #ifndef lint | |
| 0880b18e | 8 | _sccsid:.asciz "@(#)mttoggle.s 7.1 (Berkeley) %G%" |
| b1078c35 | 9 | #endif not lint |
| 1ea832bd SL |
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 |