source: buchla-68k/ram/setwq.c@ 4810254

Last change on this file since 4810254 was fa38804, checked in by Thomas Lopatic <thomas@…>, 7 years ago

Removed form-feed comments.
  • Property mode set to 100644
File size: 3.0 KB
Line 
1/*
2 ============================================================================
3 setwq.c -- word queue functions
4 Version 1 -- 1988-11-02 -- D.N. Lynx Crowe
5 ============================================================================
6*/
7
8#define WORDQHDR /* so wordq.h gets it right */
9
10#include "ram.h"
11
12/*
13 ============================================================================
14 setwq(qp, qadr, qsiz, hi, lo) -- setup a word queue
15
16 Where:
17
18 struct wordq *qp queue structure pointer
19 unsigned short *qadr queue buffer pointer
20 unsigned short qsiz maximum length of queue
21 unsigned short hi high water mark count
22 unsigned short lo low water mark count
23
24 Return value:
25
26 unsigned short qsiz size of queue
27 ============================================================================
28*/
29
30uint16_t setwq(struct wordq *qp, uint16_t *qadr, uint16_t qsiz, uint16_t hi, uint16_t lo)
31{
32 if ((uint16_t *)0L EQ qadr)
33 qsiz = 0;
34
35 qp->qbuf = qadr;
36 qp->qsize = qsiz;
37 qp->qlen = 0;
38 qp->qin = 0;
39 qp->qout = 0;
40 qp->qhi = hi;
41 qp->qlo = lo;
42
43 return(qsiz);
44}
45
46/*
47 ============================================================================
48 putwq(qp, c) -- put a word in a word queue
49
50 Where:
51
52 qp queue structure pointer
53 c word to put in the queue
54
55 Return values:
56
57 -2 error, queue size was 0
58 -1 queue was full, word not added to queue
59 0 word added to queue
60 1 at high water mark, word added to queue
61 ============================================================================
62*/
63
64int16_t putwq(struct wordq *qp, uint16_t c)
65{
66 if (0 NE qp->qsize) { /* verify queue is ok */
67
68 if (qp->qlen EQ qp->qsize) /* check queue length */
69 return(-1); /* -1 = full */
70
71 qp->qbuf[qp->qin++] = c; /* put word in queue */
72
73 if (qp->qin GE qp->qsize) /* update input index */
74 qp->qin = 0; /* wrap around */
75
76 if (++qp->qlen EQ qp->qhi) /* check length again */
77 return(1); /* 1 = at hi water */
78 else
79 return(0); /* 0 = OK */
80
81 } else {
82
83 return(-2); /* -2 = error */
84 }
85}
86
87/*
88 ============================================================================
89 getwq(qp, p) -- get a word from a word queue
90
91 Where:
92
93 qp queue structure pointer
94 p word pointer for returned word
95
96 Return values:
97
98 -2 error, queue size was 0
99 -1 queue was empty, no word returned
100 0 word returned
101 1 at low water, word returned
102 ============================================================================
103*/
104
105int16_t getwq(struct wordq *qp, uint16_t *p)
106{
107 if (0 NE qp->qsize) { /* check queue is ok */
108
109 if (0 NE qp->qlen) { /* check queue length */
110
111 *p = qp->qbuf[qp->qout++]; /* get word from queue */
112
113 if (qp->qout GE qp->qsize) /* check out pointer */
114 qp->qout = 0; /* wrap around */
115
116 if (--qp->qlen EQ qp->qlo) /* check length again */
117 return(1); /* 1 = at low water */
118 else
119 return(0); /* 0 = OK */
120
121 } else {
122
123 return(-1); /* -1 = emtpy */
124 }
125
126 } else {
127
128 return(-2); /* -2 = error */
129 }
130}
131
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