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Annotation of 40BSD/cmd/sh/stak.c, revision 1.1.1.1

1.1       root        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: }

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