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85 lines
1.3 KiB
C
85 lines
1.3 KiB
C
#include <stdint.h>
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#include "fifo.h"
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static uint8_t _fifo_get(fifo_t *f);
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void fifo_init(fifo_t *f, uint8_t *buffer, const uint8_t size)
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{
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// Backup Status Register and disable Interrupts
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uint8_t sreg = SREG;
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cli();
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f->count = 0;
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f->pread = f->pwrite = buffer;
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f->read2end = f->write2end = f->size = size;
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// Restore Status Register
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SREG = sreg;
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}
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uint8_t fifo_get_wait(fifo_t *f)
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{
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while (!f->count)
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;
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return _fifo_get(f);
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}
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int16_t fifo_get_nowait(fifo_t *f)
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{
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if (!f->count)
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return -1;
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return (int)_fifo_get(f);
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}
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uint8_t fifo_put(fifo_t *f, const uint8_t data)
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{
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if (f->count >= f->size)
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return 0;
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uint8_t *pwrite = f->pwrite;
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*(pwrite++) = data;
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uint8_t write2end = f->write2end;
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if (--write2end == 0)
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{
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write2end = f->size;
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pwrite -= write2end;
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}
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f->write2end = write2end;
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f->pwrite = pwrite;
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uint8_t sreg = SREG;
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cli();
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f->count++;
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SREG = sreg;
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return 1;
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}
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static uint8_t
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_fifo_get(fifo_t *f)
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{
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uint8_t *pread = f->pread;
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uint8_t data = *(pread++);
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uint8_t read2end = f->read2end;
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if (--read2end == 0)
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{
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read2end = f->size;
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pread -= read2end;
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}
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f->pread = pread;
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f->read2end = read2end;
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uint8_t sreg = SREG;
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cli();
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f->count--;
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SREG = sreg;
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return data;
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}
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