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| Commit | Line | Data |
|---|---|---|
| 6de44978 KT |
1 | .TH PHYS 2 PDP11 |
| 2 | .SH NAME | |
| 3 | phys \- allow a process to access physical addresses | |
| 4 | .SH SYNOPSIS | |
| 5 | .B phys(segreg, size, physadr) | |
| 6 | .SH DESCRIPTION | |
| 7 | The argument | |
| 8 | .I segreg | |
| 9 | specifies a process virtual (data-space) address | |
| 10 | range of 8K bytes starting | |
| 11 | at virtual address | |
| 12 | .IR segreg \(mu8K | |
| 13 | bytes. | |
| 14 | This address range is mapped into | |
| 15 | physical address | |
| 16 | .IR physadr \(mu64 | |
| 17 | bytes. | |
| 18 | Only the first | |
| 19 | .IR size \(mu64 | |
| 20 | bytes of this mapping is addressable. | |
| 21 | If | |
| 22 | .I size | |
| 23 | is zero, | |
| 24 | any previous mapping of this | |
| 25 | virtual address range is nullified. | |
| 26 | For example, | |
| 27 | the call | |
| 28 | .PP | |
| 29 | phys(6, 1, 0177775); | |
| 30 | .PP | |
| 31 | will map virtual addresses 0160000-0160077 into | |
| 32 | physical addresses 017777500-017777577. | |
| 33 | In particular, | |
| 34 | virtual address 0160060 is the PDP-11 console | |
| 35 | located at physical address 017777560. | |
| 36 | .PP | |
| 37 | This call may only be executed by the super-user. | |
| 38 | .SH "SEE ALSO" | |
| 39 | PDP-11 segmentation hardware | |
| 40 | .SH DIAGNOSTICS | |
| 41 | The function value zero is returned if | |
| 42 | the physical mapping is in effect. | |
| 43 | The value \-1 is returned | |
| 44 | if not super-user, | |
| 45 | if | |
| 46 | .I segreg | |
| 47 | is not in the range 0-7, | |
| 48 | if | |
| 49 | .I size | |
| 50 | is not in the range 0-127, | |
| 51 | or if | |
| 52 | the specified | |
| 53 | .I segreg | |
| 54 | is already used for other than | |
| 55 | a previous call to | |
| 56 | .IR phys . | |
| 57 | .SH BUGS | |
| 58 | This system call is obviously very machine | |
| 59 | dependent and very dangerous. | |
| 60 | This system call is not considered | |
| 61 | a permanent part of the system. | |
| 62 | .SH ASSEMBLER | |
| 63 | (phys = 52.) | |
| 64 | .br | |
| 65 | .B sys phys; segreg; size; physadr |