generic: Create generic board infrastructure and move misc.h to it

Instead of creating a misc.h file in each board directory, create a
generic board directory and declare misc.h there.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/alloc.c

@@ -0,0 +1,13 @@
+// Dummy implementation for alloc commands
+//
+// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "misc.h"
+
+// Return the maximum allocation size that can succeed up to 'reqsize'
+size_t alloc_maxsize(size_t reqsize)
+{
+    return reqsize;
+}

src/generic/crc16_ccitt.c

@@ -0,0 +1,22 @@
+// Code for crc16_ccitt
+//
+// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "misc.h" // crc16_ccitt
+
+// Implement the standard crc "ccitt" algorithm on the given buffer
+uint16_t
+crc16_ccitt(char *buf, uint8_t len)
+{
+    uint16_t crc = 0xffff;
+    while (len--) {
+        uint8_t data = *buf++;
+        data ^= crc & 0xff;
+        data ^= data << 4;
+        crc = ((((uint16_t)data << 8) | (crc >> 8)) ^ (uint8_t)(data >> 4)
+               ^ ((uint16_t)data << 3));
+    }
+    return crc;
+}

src/generic/misc.h

@@ -0,0 +1,16 @@
+#ifndef __GENERIC_MISC_H
+#define __GENERIC_MISC_H
+
+#include <stddef.h> // size_t
+#include <stdint.h> // uint8_t
+
+char *console_get_input(uint8_t *plen);
+void console_pop_input(uint8_t len);
+char *console_get_output(uint8_t len);
+void console_push_output(uint8_t len);
+
+size_t alloc_maxsize(size_t reqsize);
+
+uint16_t crc16_ccitt(char *buf, uint8_t len);
+
+#endif // misc.h