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HAL_PX4: reduce the number of times we split up UART reads and writes

This commit is contained in:
Andrew Tridgell 2014-10-09 12:27:49 +11:00
parent c834589daa
commit 10b0ca7ea8
1 changed files with 4 additions and 4 deletions
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8
libraries/AP_HAL_PX4/UARTDriver.cpp
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@ -495,13 +495,13 @@ void PX4UARTDriver::_timer_tick(void)
uint16_t _tail;
n = BUF_AVAILABLE(_writebuf);
if (n > 0) {
uint16_t n1 = _writebuf_size - _writebuf_head;
perf_begin(_perf_uart);
if (_tail > _writebuf_head) {
if (n1 >= n) {
// do as a single write
_write_fd(&_writebuf[_writebuf_head], n);
} else {
// split into two writes
uint16_t n1 = _writebuf_size - _writebuf_head;
int ret = _write_fd(&_writebuf[_writebuf_head], n1);
if (ret == n1 && n > n1) {
_write_fd(&_writebuf[_writebuf_head], n - n1);
@ -514,13 +514,13 @@ void PX4UARTDriver::_timer_tick(void)
uint16_t _head;
n = BUF_SPACE(_readbuf);
if (n > 0) {
uint16_t n1 = _readbuf_size - _readbuf_tail;
perf_begin(_perf_uart);
if (_readbuf_tail < _head) {
if (n1 >= n) {
// one read will do
assert(_readbuf_tail+n <= _readbuf_size);
_read_fd(&_readbuf[_readbuf_tail], n);
} else {
uint16_t n1 = _readbuf_size - _readbuf_tail;
assert(_readbuf_tail+n1 <= _readbuf_size);
int ret = _read_fd(&_readbuf[_readbuf_tail], n1);
if (ret == n1 && n > n1) {