[f40a309] | 1 | /*
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| 2 | ============================================================================
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| 3 | setwq.c -- word queue functions
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| 4 | Version 1 -- 1988-11-02 -- D.N. Lynx Crowe
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| 5 | ============================================================================
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| 6 | */
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| 7 |
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| 8 | #define WORDQHDR /* so wordq.h gets it right */
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| 9 |
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[b28a12e] | 10 | #include "ram.h"
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[f40a309] | 11 |
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| 12 | /*
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| 13 | ============================================================================
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| 14 | setwq(qp, qadr, qsiz, hi, lo) -- setup a word queue
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| 15 |
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| 16 | Where:
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| 17 |
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| 18 | struct wordq *qp queue structure pointer
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| 19 | unsigned short *qadr queue buffer pointer
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| 20 | unsigned short qsiz maximum length of queue
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| 21 | unsigned short hi high water mark count
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| 22 | unsigned short lo low water mark count
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| 23 |
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| 24 | Return value:
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| 25 |
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| 26 | unsigned short qsiz size of queue
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| 27 | ============================================================================
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| 28 | */
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| 29 |
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[7258c6a] | 30 | uint16_t setwq(struct wordq *qp, uint16_t *qadr, uint16_t qsiz, uint16_t hi, uint16_t lo)
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[f40a309] | 31 | {
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[7258c6a] | 32 | if ((uint16_t *)0L EQ qadr)
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[f40a309] | 33 | qsiz = 0;
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| 34 |
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| 35 | qp->qbuf = qadr;
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| 36 | qp->qsize = qsiz;
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| 37 | qp->qlen = 0;
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| 38 | qp->qin = 0;
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| 39 | qp->qout = 0;
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| 40 | qp->qhi = hi;
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| 41 | qp->qlo = lo;
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| 42 |
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| 43 | return(qsiz);
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| 44 | }
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| 45 |
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| 46 | /* |
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| 47 |
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| 48 | */
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| 49 |
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| 50 | /*
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| 51 | ============================================================================
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| 52 | putwq(qp, c) -- put a word in a word queue
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| 53 |
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| 54 | Where:
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| 55 |
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| 56 | qp queue structure pointer
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| 57 | c word to put in the queue
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| 58 |
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| 59 | Return values:
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| 60 |
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| 61 | -2 error, queue size was 0
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| 62 | -1 queue was full, word not added to queue
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| 63 | 0 word added to queue
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| 64 | 1 at high water mark, word added to queue
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| 65 | ============================================================================
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| 66 | */
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[7258c6a] | 67 |
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[f40a309] | 68 | int16_t putwq(struct wordq *qp, uint16_t c)
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| 69 | {
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| 70 | if (0 NE qp->qsize) { /* verify queue is ok */
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| 71 |
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| 72 | if (qp->qlen EQ qp->qsize) /* check queue length */
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| 73 | return(-1); /* -1 = full */
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| 74 |
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| 75 | qp->qbuf[qp->qin++] = c; /* put word in queue */
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| 76 |
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| 77 | if (qp->qin GE qp->qsize) /* update input index */
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| 78 | qp->qin = 0; /* wrap around */
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| 79 |
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| 80 | if (++qp->qlen EQ qp->qhi) /* check length again */
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| 81 | return(1); /* 1 = at hi water */
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| 82 | else
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| 83 | return(0); /* 0 = OK */
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| 84 |
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| 85 | } else {
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| 86 |
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| 87 | return(-2); /* -2 = error */
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| 88 | }
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| 89 | }
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| 90 |
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| 91 | /* |
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| 92 |
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| 93 | */
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| 94 |
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| 95 | /*
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| 96 | ============================================================================
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| 97 | getwq(qp, p) -- get a word from a word queue
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| 98 |
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| 99 | Where:
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| 100 |
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| 101 | qp queue structure pointer
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| 102 | p word pointer for returned word
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| 103 |
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| 104 | Return values:
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| 105 |
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| 106 | -2 error, queue size was 0
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| 107 | -1 queue was empty, no word returned
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| 108 | 0 word returned
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| 109 | 1 at low water, word returned
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| 110 | ============================================================================
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[7258c6a] | 111 | */
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[f40a309] | 112 |
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| 113 | int16_t getwq(struct wordq *qp, uint16_t *p)
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| 114 | {
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| 115 | if (0 NE qp->qsize) { /* check queue is ok */
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| 116 |
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| 117 | if (0 NE qp->qlen) { /* check queue length */
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| 118 |
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| 119 | *p = qp->qbuf[qp->qout++]; /* get word from queue */
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| 120 |
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| 121 | if (qp->qout GE qp->qsize) /* check out pointer */
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| 122 | qp->qout = 0; /* wrap around */
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| 123 |
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| 124 | if (--qp->qlen EQ qp->qlo) /* check length again */
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| 125 | return(1); /* 1 = at low water */
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| 126 | else
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| 127 | return(0); /* 0 = OK */
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| 128 |
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| 129 | } else {
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| 130 |
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| 131 | return(-1); /* -1 = emtpy */
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| 132 | }
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| 133 |
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| 134 | } else {
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| 135 |
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| 136 | return(-2); /* -2 = error */
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[6262b5c] | 137 | }
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| 138 | }
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| 139 |
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