Copyright © 1985 by Xerox Corporation. All rights reserved.

Andrew Birrell December 2, 1983 10:50 am

Russ Atkinson (RRA) January 30, 1985 7:02:47 pm PST

Doug Wyatt, February 22, 1985 5:53:11 pm PST

DiskFace USING [Label, PageNumber, Type],

PrincOps USING [GlobalFrameHandle, PsbIndex, PsbNull, StateVector, SVPointer],

Basics USING [BITXOR, HighHalf, LowHalf];

(this is the actual usage of PrincOps.PDA.available.)

availableA: WORD,

externalStateVector: LONG POINTER TO ExternalStateVector,

availableB: ARRAY [0..2) OF WORD

];

state(0): SVPointer, -- client's higher level state. (a short pointer in the (only) MDS).

reason(1:0..4): SwapReason,

level(1:5..15): [0..3777B],

parameter(2): POINTER TO DebugParameter,

versionident(3): CARDINAL,

loadstatepage(4): CARDINAL, -- "Basic" loadState

spare(5): CARDINAL,

vmRunTable(6): LONG POINTER TO VMRunTable,

mds(8): CARDINAL, -- MDS of *all* processes.

psb(9): PrincOps.PsbIndex ← PrincOps.PsbNull, -- PSB of current process.

loadState(10): LONG POINTER TO LoadState ← NIL, -- to "real" loadState data structure if it exists

display(12): LONG POINTER ← NIL, -- display bitmap

displayW(14), displayH(15): CARDINAL,

systemVolumeKnown(16): BOOL,

systemVolume(17): VolumeID

];

handled by user's nub

proceed(0), -- THIS MUST BE FIRST !!

start(1),

call(2),

resume(3),

quit(4),

showscreen(5),

kill(6),

handled by debugger

breakpoint(8),

worrybreak(9),

worrycall(10),

uncaughtsignal(11),

explicitcall(12),

return(13),

returnAborted(24),

(31)

};

spare: POINTER,

body: SELECT OVERLAID SwapReason FROM

];

nRuns: CARDINAL,

runs: SEQUENCE length: CARDINAL OF Run

];

page: INT, -- VM.PageNumber--

count: CARDINAL, -- number of pages in this contiguous run --

Description of the first page of the run:

deviceType: DiskFace.Type,

deviceOrdinal: CARDINAL,

diskPage: DiskFace.PageNumber, -- physical page number relative to [type,ordinal]

labelCheck: CARDINAL -- compact approximation to the label of first page of run

];

OPEN fID: LOOPHOLE[label.fileID, MACHINE DEPENDENT RECORD[a,b,c,d,e: CARDINAL]];

adj: INT = label.filePage - offset;

RETURN[ Basics.BITXOR[

};