54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
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#ifndef RING_BUFFER_H
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#define RING_BUFFER_H
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/*--------------------------------------------------------------------
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* Ring buffer to store scan codes from keyboard
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*------------------------------------------------------------------*/
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#define RBUF_SIZE 32
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static uint8_t rbuf[RBUF_SIZE];
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static uint8_t rbuf_head = 0;
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static uint8_t rbuf_tail = 0;
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static inline void rbuf_enqueue(uint8_t data)
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{
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uint8_t sreg = SREG;
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cli();
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uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
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if (next != rbuf_tail) {
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rbuf[rbuf_head] = data;
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rbuf_head = next;
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} else {
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print("rbuf: full\n");
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}
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SREG = sreg;
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}
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static inline uint8_t rbuf_dequeue(void)
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{
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uint8_t val = 0;
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uint8_t sreg = SREG;
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cli();
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if (rbuf_head != rbuf_tail) {
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val = rbuf[rbuf_tail];
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rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
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}
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SREG = sreg;
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return val;
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}
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static inline bool rbuf_has_data(void)
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{
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uint8_t sreg = SREG;
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cli();
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bool has_data = (rbuf_head != rbuf_tail);
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SREG = sreg;
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return has_data;
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}
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static inline void rbuf_clear(void)
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{
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uint8_t sreg = SREG;
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cli();
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rbuf_head = rbuf_tail = 0;
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SREG = sreg;
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}
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#endif /* RING_BUFFER_H */
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