Add initial AVR PROGMEM abstraction in hal::progmem

src/hal/progmem.h

@@ -0,0 +1,26 @@
+#pragma once
+#include <stdint.h>
+
+#ifdef __AVR__
+#include <avr/progmem.h>
+#else
+#define PROGMEM // ignored
+#endif
+
+namespace hal {
+
+/// AVR PROGMEM handling
+namespace progmem {
+
+/// read a 16bit word from PROGMEM
+static inline uint16_t pgm_read_word(const uint16_t* addr)
+{
+#ifndef __AVR__
+    return *addr;
+#else
+    return (uint16_t)::pgm_read_word(addr);
+#endif
+}
+
+} // namespace progmem
+} // namespace hal

tests/unit/hal/CMakeLists.txt

@@ -1 +1,2 @@
 add_subdirectory(circular_buffer)
+add_subdirectory(progmem)

tests/unit/hal/progmem/CMakeLists.txt

@@ -0,0 +1,8 @@
+# define the test executable
+add_executable(progmem_tests test_progmem.cpp)
+
+# define required search paths
+target_include_directories(progmem_tests PUBLIC ${CMAKE_SOURCE_DIR}/src/hal)
+
+# tell build system about the test case
+add_catch_test(progmem_tests)

tests/unit/hal/progmem/test_progmem.cpp

@@ -0,0 +1,15 @@
+#include "catch2/catch.hpp"
+#include "progmem.h"
+
+using Catch::Matchers::Equals;
+using hal::progmem::pgm_read_word;
+
+TEST_CASE("progmem::basic", "[progmem]") {
+
+    // create a PROGMEM array
+    const uint16_t arr[2] PROGMEM = {0, 1};
+
+    // ensure it can be read correctly
+    REQUIRE(0 == pgm_read_word(&arr[0]));
+    REQUIRE(1 == pgm_read_word(&arr[1]));
+}