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minimize tu_fifo size to 16

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- remove non_used_index_space
- packed overwritable with item_size
This commit is contained in:
hathach
2023-01-06 11:51:17 +07:00
parent 9c73c1a532
commit 2a1b81e3c5
3 changed files with 39 additions and 40 deletions
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37
src/common/tusb_fifo.c
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@@ -68,22 +68,19 @@ typedef enum
bool tu_fifo_config(tu_fifo_t *f, void* buffer, uint16_t depth, uint16_t item_size, bool overwritable)
{
if (depth > 0x8000) return false; // Maximum depth is 2^15 items
// Limit index space to 2*depth - this allows for a fast "modulo" calculation
// but limits the maximum depth to 2^16/2 = 2^15 and buffer overflows are detectable
// only if overflow happens once (important for unsupervised DMA applications)
if (depth > 0x8000) return false;
_ff_lock(f->mutex_wr);
_ff_lock(f->mutex_rd);
f->buffer = (uint8_t*) buffer;
f->depth = depth;
f->item_size = item_size;
f->buffer = (uint8_t*) buffer;
f->depth = depth;
f->item_size = (uint16_t) (item_size & 0x7FFF);
f->overwritable = overwritable;
// Limit index space to 2*depth - this allows for a fast "modulo" calculation
// but limits the maximum depth to 2^16/2 = 2^15 and buffer overflows are detectable
// only if overflow happens once (important for unsupervised DMA applications)
//f->max_pointer_idx = (uint16_t) (2*depth - 1);
f->non_used_index_space = (uint16_t) (UINT16_MAX - (2*f->depth-1));
f->rd_idx = f->wr_idx = 0;
_ff_unlock(f->mutex_wr);
@@ -331,7 +328,8 @@ static uint16_t advance_pointer(tu_fifo_t* f, uint16_t idx, uint16_t offset)
uint16_t next_p = (uint16_t) (idx + offset);
if ( (idx > next_p) || (next_p >= 2*f->depth) )
{
next_p = (uint16_t) (next_p + f->non_used_index_space);
uint16_t const non_used_index_space = (uint16_t) (UINT16_MAX - (2*f->depth-1));
next_p = (uint16_t) (next_p + non_used_index_space);
}
return next_p;
@@ -346,7 +344,8 @@ static uint16_t backward_pointer(tu_fifo_t* f, uint16_t p, uint16_t offset)
uint16_t new_p = (uint16_t) (p - offset);
if ( (p < new_p) || (new_p >= 2*f->depth) )
{
new_p = (uint16_t) (new_p - f->non_used_index_space);
uint16_t const non_used_index_space = (uint16_t) (UINT16_MAX - (2*f->depth-1));
new_p = (uint16_t) (new_p - non_used_index_space);
}
return new_p;
@@ -363,13 +362,15 @@ static inline uint16_t idx2ptr(uint16_t idx, uint16_t depth)
// Works on local copies of w and r - return only the difference and as such can be used to determine an overflow
static inline uint16_t _tu_fifo_count(tu_fifo_t* f, uint16_t wr_idx, uint16_t rd_idx)
{
uint16_t cnt = (uint16_t) (wr_idx-rd_idx);
uint16_t cnt;
// In case we have non-power of two depth we need a further modification
if (rd_idx > wr_idx)
if (wr_idx >= rd_idx)
{
// 2*f->depth - (rd_idx - wr_idx);
cnt = (uint16_t) (cnt - f->non_used_index_space);
cnt = (uint16_t) (wr_idx - rd_idx);
} else
{
cnt = (uint16_t) (2*f->depth - (rd_idx - wr_idx));
}
return cnt;
@@ -395,7 +396,7 @@ static inline bool _tu_fifo_full(tu_fifo_t* f, uint16_t wAbs, uint16_t rAbs)
// use DMAs, write functions do not allow such an error.
static inline bool _tu_fifo_overflowed(tu_fifo_t* f, uint16_t wr_idx, uint16_t rd_idx)
{
return (_tu_fifo_count(f, wr_idx, rd_idx) > f->depth);
return _tu_fifo_count(f, wr_idx, rd_idx) > f->depth;
}
// Works on local copies of w
@@ -868,8 +869,6 @@ bool tu_fifo_clear(tu_fifo_t *f)
_ff_lock(f->mutex_rd);
f->rd_idx = f->wr_idx = 0;
//f->max_pointer_idx = (uint16_t) (2*f->depth-1);
f->non_used_index_space = (uint16_t) (UINT16_MAX - (2*f->depth-1));
_ff_unlock(f->mutex_wr);
_ff_unlock(f->mutex_rd);