rooty/Arduino
1
0
Fork 0
mirror of https://github.com/arduino/Arduino.git synced 2025-01-18 07:52:14 +01:00
Code Issues Releases Activity

In HardwareSerial, don't use int for buffer indices

Browse Source 
The index attributes have been uint8_t for a while, so there is no point
in using int for local variables. This should allow the compiler to
generate slightly more efficient code, but (at least on gcc 4.8.2) it
also confuses the register allocator, causing this change to increase
code size by 2 bytes instead due to extra push/pop instructions (but
this will probably change in the future if the compiler improves).
This commit is contained in:
Matthijs Kooijman 2014-02-12 19:37:09 +01:00
parent 6104b2879d
commit 6372eb8c6c
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
hardware/arduino/avr/cores/arduino/HardwareSerial.cpp
View File

@ -171,7 +171,7 @@ int HardwareSerial::read(void)
return -1;
} else {
unsigned char c = _rx_buffer[_rx_buffer_tail];
_rx_buffer_tail = (unsigned int)(_rx_buffer_tail + 1) % SERIAL_BUFFER_SIZE;
_rx_buffer_tail = (uint8_t)(_rx_buffer_tail + 1) % SERIAL_BUFFER_SIZE;
return c;
}
}
@ -207,7 +207,7 @@ size_t HardwareSerial::write(uint8_t c)
sbi(*_ucsra, TXC0);
return 1;
}
int i = (_tx_buffer_head + 1) % SERIAL_BUFFER_SIZE;
uint8_t i = (_tx_buffer_head + 1) % SERIAL_BUFFER_SIZE;
// If the output buffer is full, there's nothing for it other than to
// wait for the interrupt handler to empty it a bit