4.3BSD - /usr/src/bin/sh/stak.c

   1: #ifndef lint
   2: static char sccsid[] = "@(#)stak.c	4.2 8/11/83";
   3: #endif
   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: }

Defined functions

Defined variables