-
Notifications
You must be signed in to change notification settings - Fork 2
/
fifo.c
57 lines (51 loc) · 1.17 KB
/
fifo.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
#include "bootpack.h"
void fifo32_init(struct FIFO32 *fifo, int size, int *buf){
fifo->size = size;
fifo->buf = buf;
fifo->free = size;
fifo->flags = 0;
fifo->p = 0;
fifo->q = 0;
return;
}
#define FLAGS_OVERRUN 0x0001
int fifo32_put(struct FIFO32 *fifo, int data){
//写入一个数据时
//1. 判断free是否等于0
//2. 在p处写入并增加p
//3. 如果p=size则p=0
//4. free--
if (fifo->free == 0) {
fifo->flags |= FLAGS_OVERRUN;
return -1;
}
fifo->buf[fifo->p] = data;
fifo->p++;
if (fifo->p == fifo->size) {
fifo->p = 0;
}
fifo->free--;
return 0;
}
int fifo32_get(struct FIFO32 *fifo){
//读出一个数据
//1. 判断free是否和size一样(空fifo)
//2. 从q处读出并且q++
//3. 如果q==size则q=0
//4. free++
int data;
if (fifo->free == fifo->size) {
return -1; //缓冲区为空
}
data = fifo->buf[fifo->q];
fifo->q++;
if (fifo->q == fifo->size) {
fifo->q = 0;
}
fifo->free++;
return data;
}
int fifo32_status(struct FIFO32 *fifo){
// 报告还有多少数据
return fifo->size - fifo->free;
}