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Changes to optimized digitalWrte(), etc. 

Factoring out the implementation of digitalWrite(), digitalRead(), and pinMode() into macros that can either be inlined (for constant pin numbers) or executed within a function (non-constant pins).  Removing testing for timers on pins in digitalWrite(), digitalRead(), and pinMode().  Moving pin to port macros from pins_arduino.h to wiring.h.
This commit is contained in:
David A. Mellis 2011-02-11 19:29:46 -05:00
parent 3696fa0446
commit eed15e48d6
3 changed files with 116 additions and 154 deletions
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46
cores/arduino/pins_arduino.h
View File

@ -339,6 +339,8 @@ INLINED uint8_t inlined_digitalPinToBitMask(uint8_t pin)
}
}
// XXX: this needs to return false (or -1) if the pin doesn't have a timer,
// rather than throwing a compilation error.
INLINED uint8_t inlined_digitalPinToTimer(uint8_t pin)
{
switch(pin) {
@ -453,6 +455,8 @@ INLINED uint8_t inlined_digitalPinToBitMask(uint8_t pin)
}
}
// XXX: this needs to return false (or -1) if the pin doesn't have a timer,
// rather than throwing a compilation error.
INLINED uint8_t inlined_digitalPinToTimer(uint8_t pin)
{
switch(pin) {
@ -477,46 +481,4 @@ INLINED uint8_t inlined_digitalPinToTimer(uint8_t pin)
#define analogInPinToBit(P) (P)
INLINED uint8_t digitalPinToPort(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToPort(pin);
else
return pgm_read_byte( digital_pin_to_port_PGM + pin );
}
INLINED uint8_t digitalPinToBitMask(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToBitMask(pin);
else
return pgm_read_byte( digital_pin_to_bit_mask_PGM + pin );
}
INLINED uint8_t digitalPinToTimer(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToTimer(pin);
else
return pgm_read_byte( digital_pin_to_timer_PGM + pin );
}
INLINED volatile uint8_t *portOutputRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portOutputRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_output_PGM + index ) );
}
INLINED volatile uint8_t* portInputRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portInputRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_input_PGM + index) );
}
INLINED volatile uint8_t* portModeRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portModeRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_mode_PGM + index) );
}
#endif

146
cores/arduino/wiring.h
View File

@ -130,68 +130,136 @@ void detachInterrupt(uint8_t);
void setup(void);
void loop(void);
INLINED uint8_t digitalPinToPort(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToPort(pin);
else
return pgm_read_byte( digital_pin_to_port_PGM + pin );
}
INLINED uint8_t digitalPinToBitMask(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToBitMask(pin);
else
return pgm_read_byte( digital_pin_to_bit_mask_PGM + pin );
}
INLINED uint8_t digitalPinToTimer(uint8_t pin) {
if (__builtin_constant_p(pin))
return inlined_digitalPinToTimer(pin);
else
return pgm_read_byte( digital_pin_to_timer_PGM + pin );
}
INLINED volatile uint8_t *portOutputRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portOutputRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_output_PGM + index ) );
}
INLINED volatile uint8_t* portInputRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portInputRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_input_PGM + index) );
}
INLINED volatile uint8_t* portModeRegister(uint8_t index) {
if (__builtin_constant_p(index))
return inlined_portModeRegister(index);
else
return (volatile uint8_t *)( pgm_read_word( port_to_mode_PGM + index) );
}
/*
* Check if a given pin requires locking.
* When accessing lower 32 IO ports we can use SBI/CBI instructions, which are atomic. However
* other IO ports require load+modify+store and we need to make them atomic by disabling
* interrupts.
*/
INLINED int portWriteNeedsLocking(uint8_t pin)
INLINED int registerWriteNeedsLocking(volatile uint8_t *reg)
{
/* SBI/CBI instructions only work on lower 32 IO ports */
if (inlined_portOutputRegister(inlined_digitalPinToPort(pin)) > (volatile uint8_t*)&_SFR_IO8(0x1F)) {
if (reg > (volatile uint8_t*)&_SFR_IO8(0x1F)) {
return 1;
}
return 0;
}
/*
* These functions will perform OR/AND on a given register, and are atomic.
*/
extern void __digitalWriteOR_locked(volatile uint8_t*out, uint8_t bit);
extern void __digitalWriteAND_locked(volatile uint8_t*out, uint8_t bit);
#define digitalWrite_implementation(pin, value)\
do {\
uint8_t oldSREG;\
uint8_t bit = digitalPinToBitMask(pin);\
uint8_t port = digitalPinToPort(pin);\
volatile uint8_t *reg = portOutputRegister(port);\
\
if (!__builtin_constant_p(pin) || registerWriteNeedsLocking(reg)) {\
oldSREG = SREG;\
cli();\
}\
\
if (value == LOW) {\
*reg &= ~bit;\
} else {\
*reg |= bit;\
}\
\
if (!__builtin_constant_p(pin) || registerWriteNeedsLocking(reg)) {\
SREG = oldSREG;\
}\
} while(0)
INLINED void digitalWrite(uint8_t pin, uint8_t value)
{
if (__builtin_constant_p(pin)) {
if (portWriteNeedsLocking(pin)) {
if (value==LOW) {
__digitalWriteAND_locked(inlined_portOutputRegister(inlined_digitalPinToPort(pin)),~inlined_digitalPinToBitMask(pin));
} else {
__digitalWriteOR_locked(inlined_portOutputRegister(inlined_digitalPinToPort(pin)),inlined_digitalPinToBitMask(pin));
}
} else {
if (value==LOW) {
*inlined_portOutputRegister(inlined_digitalPinToPort(pin)) &= ~(inlined_digitalPinToBitMask(pin));
} else {
*inlined_portOutputRegister(inlined_digitalPinToPort(pin)) |= inlined_digitalPinToBitMask(pin);
}
}
} else {
digitalWrite_lookup(pin,value);
}
if (__builtin_constant_p(pin)) digitalWrite_implementation(pin, value);
else digitalWrite_lookup(pin, value);
}
INLINED void pinMode(uint8_t pin, uint8_t mode)
#define pinMode_implementation(pin, value)\
do {\
uint8_t bit = digitalPinToBitMask(pin);\
uint8_t oldSREG;\
uint8_t port = digitalPinToPort(pin);\
volatile uint8_t *reg = portModeRegister(port);\
\
if (!__builtin_constant_p(pin) || registerWriteNeedsLocking(reg)) {\
oldSREG = SREG;\
cli();\
}\
\
if (value == INPUT) { \
*reg &= ~bit;\
} else {\
*reg |= bit;\
}\
\
if (!__builtin_constant_p(pin) || registerWriteNeedsLocking(reg)) {\
SREG = oldSREG;\
}\
} while(0)
INLINED void pinMode(uint8_t pin, uint8_t value)
{
if (__builtin_constant_p(pin)) {
if (mode==INPUT) {
*inlined_portModeRegister(inlined_digitalPinToPort(pin)) &= ~(inlined_digitalPinToBitMask(pin));
} else {
*inlined_portModeRegister(inlined_digitalPinToPort(pin)) |= inlined_digitalPinToBitMask(pin);
}
} else {
pinMode_lookup(pin,mode);
}
if (__builtin_constant_p(pin)) pinMode_implementation(pin, value);
else pinMode_lookup(pin, value);
}
#define digitalRead_implementation(pin)\
do {\
uint8_t bit = digitalPinToBitMask(pin);\
uint8_t port = digitalPinToPort(pin);\
\
if (port == NOT_A_PIN) return LOW;\
\
if (*portInputRegister(port) & bit) return HIGH;\
return LOW;\
} while(0)
INLINED int digitalRead(uint8_t pin)
{
if (__builtin_constant_p(pin)) {
return !! *inlined_portInputRegister(inlined_digitalPinToPort(pin));
} else {
return digitalRead_lookup(pin);
}
if (__builtin_constant_p(pin)) digitalRead_implementation(pin);
else return digitalRead_lookup(pin);
}

76
cores/arduino/wiring_digital.c
View File

@ -27,28 +27,9 @@
#include "wiring_private.h"
#include "pins_arduino.h"
void pinMode_lookup(uint8_t pin, uint8_t mode)
void pinMode_lookup(uint8_t pin, uint8_t val)
{
uint8_t bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
volatile uint8_t *reg;
if (port == NOT_A_PIN) return;
// JWS: can I let the optimizer do this?
reg = portModeRegister(port);
if (mode == INPUT) {
uint8_t oldSREG = SREG;
cli();
*reg &= ~bit;
SREG = oldSREG;
} else {
uint8_t oldSREG = SREG;
cli();
*reg |= bit;
SREG = oldSREG;
}
pinMode_implementation(pin, val);
}
// Forcing this inline keeps the callers from having to push their own stuff
@ -121,61 +102,12 @@ static void turnOffPWM(uint8_t timer)
}
}
void __digitalWriteOR_locked(volatile uint8_t*out, uint8_t bit)
{
uint8_t oldSREG = SREG;
cli();
*out |= bit;
SREG=oldSREG;
}
void __digitalWriteAND_locked(volatile uint8_t*out, uint8_t bit)
{
uint8_t oldSREG = SREG;
cli();
*out &= bit; // NOTE - no inversion here, invert before calling!!!
SREG=oldSREG;
}
void digitalWrite_lookup(uint8_t pin, uint8_t val)
{
uint8_t timer = digitalPinToTimer(pin);
uint8_t bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
volatile uint8_t *out;
if (port == NOT_A_PIN) return;
// If the pin that support PWM output, we need to turn it off
// before doing a digital write.
if (timer != NOT_ON_TIMER) turnOffPWM(timer);
out = portOutputRegister(port);
uint8_t oldSREG = SREG;
cli();
if (val == LOW) {
*out &= ~bit;
} else {
*out |= bit;
}
SREG = oldSREG;
digitalWrite_implementation(pin, val);
}
int digitalRead_lookup(uint8_t pin)
{
uint8_t timer = digitalPinToTimer(pin);
uint8_t bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
if (port == NOT_A_PIN) return LOW;
// If the pin that support PWM output, we need to turn it off
// before getting a digital reading.
if (timer != NOT_ON_TIMER) turnOffPWM(timer);
if (*portInputRegister(port) & bit) return HIGH;
return LOW;
digitalRead_implementation(pin);
}