tweak pinMode code

Author: nerdralph

library.properties

@@ -1,5 +1,5 @@
 name=ArduinoShrink
-version=0.7.0
+version=0.7.1
 author=Ralph Doncaster
 maintainer=
 sentence=

src/as_wdigital.c

@@ -0,0 +1,73 @@
+// (c) Ralph Doncaster 2020
+// thanks to Bill W for inspiration
+// github.com/WestfW/Duino-hacks/blob/master/fastdigitalIO/fastdigitalIO.h 
+// 20200709 v0.1.0 release
+// 20200410 alias _to_xxx_PGM[] arrays as __flash for runtime pin manipulation
+
+#include <stdint.h>
+#include <avr/io.h>
+
+// todo: use constants.h from PicoCore
+enum {LOW, HIGH};                       // for digitalWrite()
+enum {INPUT, OUTPUT, INPUT_PULLUP};     // for pinMode()
+
+extern __flash const uint16_t port_to_output_PGM[];
+extern __flash const uint8_t digital_pin_to_port_PGM[];
+extern __flash const uint8_t digital_pin_to_bit_mask_PGM[];
+
+typedef volatile uint8_t* ioreg_p;
+
+#define ALWAYS_INLINE __attribute__((always_inline)) inline
+
+ALWAYS_INLINE ioreg_p pin_to_port(uint8_t pin)
+{
+    // use pointer instead of array operators due to avr-gcc bug:
+    // https://www.avrfreaks.net/forum/avr-gcc-have-i-told-you-lately-i-hate-you
+    //return (ioreg_p) port_to_output_PGM[digital_pin_to_port_PGM[pin]];
+    return (ioreg_p) *(port_to_output_PGM + *(digital_pin_to_port_PGM +pin));
+}
+
+ALWAYS_INLINE ioreg_p pin_to_ddr(uint8_t pin)
+{
+    // DDR address is 1 less than PORT address
+    return pin_to_port(pin) - 1;
+}
+
+ALWAYS_INLINE ioreg_p pin_to_pinreg(uint8_t pin)
+{
+    // PIN address is 2 less than PORT address
+    return pin_to_port(pin) - 2;
+}
+
+ALWAYS_INLINE uint8_t pin_to_bit(uint8_t pin)
+{
+    //return digital_pin_to_bit_mask_PGM[pin];
+    return *(digital_pin_to_bit_mask_PGM + pin);
+}
+
+void pinMode(uint8_t pin, uint8_t mode)
+{
+    ioreg_p ddr = pin_to_ddr(pin);
+    uint8_t bit = pin_to_bit(pin);
+    if (mode == OUTPUT)
+        *ddr|= bit;
+    else {
+        *ddr &= ~bit;
+        if (mode == INPUT_PULLUP) *pin_to_port(pin) |= bit;
+    }
+}
+
+void digitalWrite(uint8_t pin, uint8_t val)
+{
+    ioreg_p port = pin_to_ddr(pin);
+    uint8_t bit = pin_to_bit(pin);
+    if (val == LOW)
+        *port &= ~bit;
+    else                                // HIGH
+        *port |= bit;
+}
+
+int digitalRead(uint8_t pin)
+{
+    return (*pin_to_pinreg(pin) & pin_to_bit(pin)) ? HIGH : LOW;
+}