Commit | Line | Data |
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f6227721 SL |
1 | #ifndef lint |
2 | static char sccsid[] = "@(#)stak.c 4.2 %G%"; | |
3 | #endif | |
0ac28e48 KM |
4 | |
5 | # | |
6 | /* | |
7 | * UNIX shell | |
8 | * | |
9 | * S. R. Bourne | |
10 | * Bell Telephone Laboratories | |
11 | * | |
12 | */ | |
13 | ||
14 | #include "defs.h" | |
15 | ||
16 | STKPTR stakbot=nullstr; | |
17 | ||
18 | ||
19 | ||
20 | /* ======== storage allocation ======== */ | |
21 | ||
22 | STKPTR getstak(asize) | |
23 | INT asize; | |
24 | { /* allocate requested stack */ | |
25 | REG STKPTR oldstak; | |
26 | REG INT size; | |
27 | ||
28 | size=round(asize,BYTESPERWORD); | |
29 | oldstak=stakbot; | |
30 | staktop = stakbot += size; | |
31 | return(oldstak); | |
32 | } | |
33 | ||
34 | STKPTR locstak() | |
35 | { /* set up stack for local use | |
36 | * should be followed by `endstak' | |
37 | */ | |
38 | IF brkend-stakbot<BRKINCR | |
39 | THEN setbrk(brkincr); | |
40 | IF brkincr < BRKMAX | |
41 | THEN brkincr += 256; | |
42 | FI | |
43 | FI | |
44 | return(stakbot); | |
45 | } | |
46 | ||
47 | STKPTR savstak() | |
48 | { | |
49 | assert(staktop==stakbot); | |
50 | return(stakbot); | |
51 | } | |
52 | ||
53 | STKPTR endstak(argp) | |
54 | REG STRING argp; | |
55 | { /* tidy up after `locstak' */ | |
56 | REG STKPTR oldstak; | |
57 | *argp++=0; | |
58 | oldstak=stakbot; stakbot=staktop=round(argp,BYTESPERWORD); | |
59 | return(oldstak); | |
60 | } | |
61 | ||
62 | VOID tdystak(x) | |
63 | REG STKPTR x; | |
64 | { | |
65 | /* try to bring stack back to x */ | |
66 | WHILE ADR(stakbsy)>ADR(x) | |
67 | DO free(stakbsy); | |
68 | stakbsy = stakbsy->word; | |
69 | OD | |
70 | staktop=stakbot=max(ADR(x),ADR(stakbas)); | |
71 | rmtemp(x); | |
72 | } | |
73 | ||
74 | stakchk() | |
75 | { | |
76 | IF (brkend-stakbas)>BRKINCR+BRKINCR | |
77 | THEN setbrk(-BRKINCR); | |
78 | FI | |
79 | } | |
80 | ||
81 | STKPTR cpystak(x) | |
82 | STKPTR x; | |
83 | { | |
84 | return(endstak(movstr(x,locstak()))); | |
85 | } |