Commit | Line | Data |
---|---|---|
862515b8 TL |
1 | # |
2 | /* | |
3 | * UNIX shell | |
4 | * | |
5 | * S. R. Bourne | |
6 | * Bell Telephone Laboratories | |
7 | * | |
8 | */ | |
9 | ||
10 | #include "defs.h" | |
11 | ||
12 | STKPTR stakbot=nullstr; | |
13 | ||
14 | ||
15 | ||
16 | /* ======== storage allocation ======== */ | |
17 | ||
18 | STKPTR getstak(asize) | |
19 | INT asize; | |
20 | { /* allocate requested stack */ | |
21 | REG STKPTR oldstak; | |
22 | REG INT size; | |
23 | ||
24 | size=round(asize,BYTESPERWORD); | |
25 | oldstak=stakbot; | |
26 | staktop = stakbot += size; | |
27 | return(oldstak); | |
28 | } | |
29 | ||
30 | STKPTR locstak() | |
31 | { /* set up stack for local use | |
32 | * should be followed by `endstak' | |
33 | */ | |
34 | IF brkend-stakbot<BRKINCR | |
35 | THEN setbrk(brkincr); | |
36 | IF brkincr < BRKMAX | |
37 | THEN brkincr += 256; | |
38 | FI | |
39 | FI | |
40 | return(stakbot); | |
41 | } | |
42 | ||
43 | STKPTR savstak() | |
44 | { | |
45 | assert(staktop==stakbot); | |
46 | return(stakbot); | |
47 | } | |
48 | ||
49 | STKPTR endstak(argp) | |
50 | REG STRING argp; | |
51 | { /* tidy up after `locstak' */ | |
52 | REG STKPTR oldstak; | |
53 | *argp++=0; | |
54 | oldstak=stakbot; stakbot=staktop=round(argp,BYTESPERWORD); | |
55 | return(oldstak); | |
56 | } | |
57 | ||
58 | VOID tdystak(x) | |
59 | REG STKPTR x; | |
60 | { | |
61 | /* try to bring stack back to x */ | |
62 | WHILE ADR(stakbsy)>ADR(x) | |
63 | DO free(stakbsy); | |
64 | stakbsy = stakbsy->word; | |
65 | OD | |
66 | staktop=stakbot=max(ADR(x),ADR(stakbas)); | |
67 | rmtemp(x); | |
68 | } | |
69 | ||
70 | stakchk() | |
71 | { | |
72 | IF (brkend-stakbas)>BRKINCR+BRKINCR | |
73 | THEN setbrk(-BRKINCR); | |
74 | FI | |
75 | } | |
76 | ||
77 | STKPTR cpystak(x) | |
78 | STKPTR x; | |
79 | { | |
80 | return(endstak(movstr(x,locstak()))); | |
81 | } |