Unify ESP32/ESP8266 use of IRAM_ATTR (#202)

Replace ICACHE_RAM_ATTR with IRAM_ATTR in the few places it was still
present, to unify the ESP32 and ESP8266 codepaths.  ESP8266 core is
deprecating the ICACHE_RAM_ATTR define in 3.0.0:
esp8266/Arduino#7921

Author: earlephilhower

src/SoftwareSerial.cpp

@@ -245,7 +245,7 @@ int SoftwareSerial::available() {
     return avail;
 }
 
-void ICACHE_RAM_ATTR SoftwareSerial::preciseDelay(bool sync) {
+void IRAM_ATTR SoftwareSerial::preciseDelay(bool sync) {
     if (!sync)
     {
         // Reenable interrupts while delaying to avoid other tasks piling up
@@ -276,7 +276,7 @@ void ICACHE_RAM_ATTR SoftwareSerial::preciseDelay(bool sync) {
     m_periodStart = ESP.getCycleCount();
 }
 
-void ICACHE_RAM_ATTR SoftwareSerial::writePeriod(
+void IRAM_ATTR SoftwareSerial::writePeriod(
     uint32_t dutyCycle, uint32_t offCycle, bool withStopBit) {
     preciseDelay(true);
     if (dutyCycle)
@@ -305,7 +305,7 @@ size_t SoftwareSerial::write(const uint8_t* buffer, size_t size) {
     return write(buffer, size, m_parityMode);
 }
 
-size_t ICACHE_RAM_ATTR SoftwareSerial::write(const uint8_t* buffer, size_t size, SoftwareSerialParity parity) {
+size_t IRAM_ATTR SoftwareSerial::write(const uint8_t* buffer, size_t size, SoftwareSerialParity parity) {
     if (m_rxValid) { rxBits(); }
     if (!m_txValid) { return -1; }
 
@@ -525,7 +525,7 @@ void SoftwareSerial::rxBits(const uint32_t& isrCycle) {
     }
 }
 
-void ICACHE_RAM_ATTR SoftwareSerial::rxBitISR(SoftwareSerial* self) {
+void IRAM_ATTR SoftwareSerial::rxBitISR(SoftwareSerial* self) {
     uint32_t curCycle = ESP.getCycleCount();
     bool level = digitalRead(self->m_rxPin);
 
@@ -534,7 +534,7 @@ void ICACHE_RAM_ATTR SoftwareSerial::rxBitISR(SoftwareSerial* self) {
     if (!self->m_isrBuffer->push((curCycle | 1U) ^ !level)) self->m_isrOverflow.store(true);
 }
 
-void ICACHE_RAM_ATTR SoftwareSerial::rxBitSyncISR(SoftwareSerial* self) {
+void IRAM_ATTR SoftwareSerial::rxBitSyncISR(SoftwareSerial* self) {
     uint32_t start = ESP.getCycleCount();
     uint32_t wait = self->m_bitCycles - 172U;
 

src/circular_queue/Delegate.h

@@ -25,7 +25,6 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #elif defined(ESP32)
 #include <esp_attr.h>
 #else
-#define ICACHE_RAM_ATTR
 #define IRAM_ATTR
 #endif
 

src/circular_queue/circular_queue.h

@@ -35,7 +35,6 @@ using std::min;
 #endif
 
 #if !defined(ESP32) && !defined(ESP8266)
-#define ICACHE_RAM_ATTR
 #define IRAM_ATTR
 #endif