1 09/10/87  Virtual Pointers
 2 
 3 The cv_ptr_ function converts virtual pointers that contain one or two
 4 components -- a segment identifier and an optional offset into the
 5 segment.  Altogether, seventeen forms are accepted.  They are shown in
 6 the list below.
 7 
 8 In the list that follows, W is an octal word offset from the beginning
 9 of the segment.  It may have a value from 0 to 777777 inclusive.  B is
10 a decimal bit offset within the word.  It may have a value from 0 to 35
11 inclusive.
12 
13 
14 List of virtual pointers:
15 path|W(B)
16    points to octal word W, decimal bit B of segment or MSF identified
17    by absolute or relative pathname path.  If the path given identifies
18    a multisegment file, the offset given is in component 0 of the MSF.
19 path|W
20    same as path|W(0).
21 path|
22    same as path|0(0).
23 path
24    same as path|0(0).
25 path|entry_pt
26    points to word identified by entry point entry_pt in the object file
27    (segment or MSF) identified by path.
28 
29 
30 dir>entry$entry_pt
31    points to word identified by entry point entry_pt in the object file
32    identified by pathname dir>entry.
33 <dir>entry$entry_pt
34    points to word identified by entry point entry_pt in the object file
35    identified by pathname <dir>entry.
36 <entry$entry_pt
37    points to word identified by entry point entry_pt in the object file
38    identified by pathname <entry.
39 
40 
41 ref_name$entry_pt
42    points to word identified by entry point entry_pt in the file whose
43    reference name is ref_name.
44 ref_name$W(B)
45    points to octal word W, decimal bit B of segment or MSF whose
46    reference name is ref_name.  If ref_name is a reference name on a
47    multisegment file (ie. on component 0 of the MSF), the word and bit
48    offsets are applied within component 0.
49 ref_name$W
50    same as ref_name$W(0).
51 ref_name$
52    same as ref_name$0(0).
53 
54 
55 segno|W(B)
56    points to octal word W, decimal bit B of segment whose octal
57    segment number is segno.
58 segno|W
59    same as segno|W(0).
60 segno|
61    same as segno|0(0).
62 segno
63    same as segno|0(0).
64 segno|entry_pt
65    points to word identified by entry point entry_pt in segment whose
66    octal segment number is segno.  If segno identifies component 0 of
67    an object MSF, the pointer returned may not point within the segment
68    identified, since the target of a definition in component 0 of an
69    object MSF will be in another component of the object MSF.
70 
71 
72 Notes:  A null pointer is represented by the virtual pointer 77777|1,
73 by -1|1, or by -1.