smoothie: bitbanded gpio

pin.patch

diff --git a/src/libs/Pin.cpp b/src/libs/Pin.cpp
index bc234d2..3190935 100644
--- a/src/libs/Pin.cpp
+++ b/src/libs/Pin.cpp
@@ -4,6 +4,7 @@

 Pin::Pin(){
     this->inverting= false;
+    bitband = NULL;
 }

 // Make a new pin object from a string
@@ -33,6 +34,8 @@ Pin* Pin::from_string(std::string value){
             if ((cn > cs) && (pin < 32)){
                 this->port->FIOMASK &= ~(1 << this->pin);

+                bitband = (uint32_t*) (0x22000000 + ((((uintptr_t) &(port->FIOPIN)) - 0x20000000) * 32 + pin * 4));
+
                 // now check for modifiers:-
                 // ! = invert pin
                 // o = set pin to open drain
@@ -76,6 +79,7 @@ Pin* Pin::from_string(std::string value){
     port = gpios[0];
     pin = 255;
     inverting = false;
+    bitband = NULL;
     return this;
 }

diff --git a/src/libs/Pin.h b/src/libs/Pin.h
index d64592f..89e76a6 100644
--- a/src/libs/Pin.h
+++ b/src/libs/Pin.h
@@ -47,17 +47,17 @@ class Pin {

         inline void set(bool value)
         {
-            if (this->pin >= 32) return;
-            if ( this->inverting ^ value )
-                this->port->FIOSET = 1 << this->pin;
-            else
-                this->port->FIOCLR = 1 << this->pin;
+            if (bitband == NULL)
+                return;
+            *bitband = inverting ^ value;
         }

         LPC_GPIO_TypeDef* port;
         bool inverting;
         char port_number;
         unsigned char pin;
+
+        uint32_t* bitband;
 };