sys: Module to access architecture details

Add a platform independent way to access architecture details. Currently only
macros to query word size, word sized integer types, and a type qualifier for
aligning variables to word boundaries are provided.

sys/include/architecture.h

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2020 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @defgroup    sys_architecture    Platform-independent access to architecture
+ *                                  details
+ * @ingroup     sys
+ *
+ * This module provides architecture-independent access to architecture details.
+ *
+ * @{
+ *
+ * @file
+ * @brief       Platform-independent access to architecture details
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ */
+
+#ifndef ARCHITECTURE_H
+#define ARCHITECTURE_H
+
+#include <stdint.h>
+
+#include "architecture_arch.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Provide doxygen doc centrally, instead of in every architecture_arch.h */
+#ifdef DOXYGEN
+/**
+ * @brief   Size of a word in bits
+ *
+ * @details Depending on architecture, this can have a value of 8, 16, or 32
+ */
+#define ARCHITECTURE_WORD_BITS      <NUM>
+/**
+ * @brief   Size of a word in bytes
+ *
+ * @details Depending on architecture, this can have a value or 1, 2, or 4.
+ */
+#define ARCHITECTURE_WORD_BYTES     <NUM>
+/**
+ * @brief   Word sized unsigned integer
+ *
+ * @details Synonym to `uint8_t`, `uint16_t` or `uint32_t` depending on
+ *          architecture
+ */
+typedef uint<num>_t uword_t;
+/**
+ * @brief   Word sized signed integer
+ *
+ * @details Synonym to `int8_t`, `int16_t` or `int32_t` depending on
+ *          architecture
+ */
+typedef int<num>_t  sword_t;
+#elif (ARCHITECTURE_WORD_BITS == 8)
+#define ARCHITECTURE_WORD_BYTES     (1U)
+typedef uint8_t     uword_t;
+typedef int8_t      sword_t;
+#elif (ARCHITECTURE_WORD_BITS == 16)
+#define ARCHITECTURE_WORD_BYTES     (2U)
+typedef uint16_t    uword_t;
+typedef int16_t     sword_t;
+#elif (ARCHITECTURE_WORD_BITS == 32)
+#define ARCHITECTURE_WORD_BYTES     (4U)
+typedef uint32_t    uword_t;
+typedef int32_t     sword_t;
+#else
+#error  "Unsupported word size (check ARCHITECTURE_WORD_BITS in architecture_arch.h)"
+#endif
+
+/**
+ * @brief   Type qualifier to use to align data on word boundaries
+ *
+ * Use like this:
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.c}
+ * char WORD_ALIGNED thread_stack[THREAD_STACKSIZE_DEFAULT];
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+#define WORD_ALIGNED __attribute__((aligned(ARCHITECTURE_WORD_BYTES)))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ARCHITECTURE_H */
+/** @} */