31      *  head --v-- tail             used = 0  in test_fifo8_pop_bufptr_wrap()
37      *  head --v      ]-- tail      used = 4  in test_fifo8_pop_bufptr_wrap()
42      *      head --v  ]-- tail      used = 2  in test_fifo8_pop_bufptr_wrap()
51      *     tail --]v-- head         used = 8  in test_fifo8_pop_bufptr_wrap()
56      *  head --v  ]-- tail          used = 2  in test_fifo8_pop_bufptr_wrap()
77      *  head --v-- tail             used = 0  in test_fifo8_pop_bufptr()
83      *  head --v      ]-- tail      used = 4  in test_fifo8_pop_bufptr()
88      *      head --v  ]-- tail      used = 2  in test_fifo8_pop_bufptr()
109      *  head --v-- tail             used = 0  in test_fifo8_peek_bufptr_wrap()
115      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_bufptr_wrap()
120      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_bufptr_wrap()
129      *     head  --v  ]-- tail      used = 2  in test_fifo8_peek_bufptr_wrap()
137      *  tail   ---]v-- head         used = 8  in test_fifo8_peek_bufptr_wrap()
143      *     tail --]v-- head         used = 8  in test_fifo8_peek_bufptr_wrap()
164      *  head --v-- tail             used = 0  in test_fifo8_peek_bufptr()
170      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_bufptr()
175      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_bufptr()
196      *  head --v-- tail             used = 0  in test_fifo8_pop_buf_wrap()
202      *  head --v      ]-- tail      used = 4  in test_fifo8_pop_buf_wrap()
207      *         tail --]v-- head     used = 0  in test_fifo8_pop_buf_wrap()
213      *         tail --]v-- head     used = 8  in test_fifo8_pop_buf_wrap()
218      * head  --v      ]-- tail      used = 4  in test_fifo8_pop_buf_wrap()
224      *         tail --]v-- head     used = 0  in test_fifo8_pop_buf_wrap()
244      *  head --v-- tail             used = 0  in test_fifo8_pop_buf()
250      *  head --v      ]-- tail      used = 4  in test_fifo8_pop_buf()
255      *         tail --]v-- head     used = 0  in test_fifo8_pop_buf()
277      *  head --v-- tail             used = 0  in test_fifo8_peek_buf_wrap()
283      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_buf_wrap()
288      *         tail --]v-- head     used = 0  in test_fifo8_peek_buf_wrap()
294      *         tail --]v-- head     used = 8  in test_fifo8_peek_buf_wrap()
301      *         tail --]v-- head     used = 8  in test_fifo8_peek_buf_wrap()
311      *         tail --]v-- head     used = 8  in test_fifo8_peek_buf_wrap()
334      *  head --v-- tail             used = 0  in test_fifo8_peek_buf()
340      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_buf()
350      *  head --v      ]-- tail      used = 4  in test_fifo8_peek_buf()
369      *  head --v-- tail             used = 0  in test_fifo8_peek()
374      *  head --v]-- tail            used = 1  in test_fifo8_peek()
379      *  head --v  ]-- tail          used = 2  in test_fifo8_peek()
387      *    head --v]-- tail          used = 1  in test_fifo8_peek()
404      *  head --v-- tail             used = 0  in test_fifo8_pushpop()
409      *  head --v]-- tail            used = 1  in test_fifo8_pushpop()
414      *  head --v  ]-- tail          used = 2  in test_fifo8_pushpop()
420      *    head --v]-- tail          used = 1  in test_fifo8_pushpop()
426      *     tail --]v-- head         used = 0  in test_fifo8_pushpop()