Added Classes vs Struct example

coder137 · coder137 · commit 88fc1a8a2775 · 2020-07-29T11:47:44.000-07:00
diff --git a/Baremetal/Cpp/Minimal_Cpp/CMakeLists.txt b/Baremetal/Cpp/Minimal_Cpp/CMakeLists.txt
@@ -8,7 +8,20 @@ set(CMAKE_TOOLCHAIN_FILE "toolchain.cmake")
 project(${PROJECT_NAME})
 
 set(USER_PROJECT_TARGET "${PROJECT_NAME}.elf")
-add_executable(${USER_PROJECT_TARGET} src/main.cpp src/isr_vector.c)
+
+# ~~~
+# Functions vs Namespaces
+# add_executable(
+#   ${USER_PROJECT_TARGET}
+#   # src/main.c
+#   src/main.cpp src/isr_vector.c)
+# ~~~
+
+# Classes vs Structs
+add_executable(
+  ${USER_PROJECT_TARGET}
+  # src/class/main.c
+  src/class/main.cpp src/isr_vector.c)
 
 # TODO, Add more files here
 
diff --git a/Baremetal/Cpp/Minimal_Cpp/src/class/main.c b/Baremetal/Cpp/Minimal_Cpp/src/class/main.c
@@ -0,0 +1,62 @@
+#include "stm32l475xx.h"
+#include <stdint.h>
+
+typedef struct {
+  GPIO_TypeDef *port;
+  uint8_t pin;
+} Blink;
+
+void init(Blink *blink);
+void set(Blink *blink);
+void reset(Blink *blink);
+void spin_delay(Blink *blink, uint32_t delay);
+
+int main(void) {
+  Blink blink = {GPIOA, 5};
+
+  init(&blink);
+  set(&blink);
+  spin_delay(&blink, 1000 * 1000);
+
+  while (1) {
+    reset(&blink);
+    spin_delay(&blink, 1000 * 1000);
+
+    set(&blink);
+    spin_delay(&blink, 1000 * 1000);
+  }
+
+  return 0;
+}
+
+void init(Blink *blink) {
+  RCC->AHB2ENR |= RCC_AHB2ENR_GPIOAEN;
+  blink->port->BRR |= (1 << blink->pin); // Reset the pin here
+
+  // Set the mode
+  blink->port->MODER &= ~(3 << (blink->pin * 2));
+  blink->port->MODER |= (1 << (blink->pin * 2)); // 01 00 00 00 00 00
+
+  // Check these registers
+  blink->port->OTYPER &= ~(1 << blink->pin); // set to 0
+  blink->port->OSPEEDR &= ~(3 << (blink->pin * 2));
+  blink->port->PUPDR &= ~(3 << (blink->pin * 2));
+}
+
+void set(Blink *blink) {
+  // Set the pin here
+  blink->port->BSRR |= (1 << blink->pin);
+}
+
+void reset(Blink *blink) {
+  blink->port->BRR = (1 << blink->pin); // Reset
+}
+
+void spin_delay(Blink *blink, uint32_t delay) {
+  (void)blink;
+
+  while (delay) {
+    __NOP();
+    --delay;
+  }
+}
diff --git a/Baremetal/Cpp/Minimal_Cpp/src/class/main.cpp b/Baremetal/Cpp/Minimal_Cpp/src/class/main.cpp
@@ -0,0 +1,83 @@
+/**
+ *
+ * Having a constructor (and destructor) increases the binary size by 4 bytes
+ * over its C counter part
+ * However code generation for both C and C++ strictly results in the same
+ * binary output if (constructor and destructors arent used)
+ *
+ * C with Struct without args = 1152
+ * C++ with Classes without args (without constructor) = 1152
+ * C++ with Classes without args (with constructor) = 1156
+ *
+ * C with Struct with args = 1188
+ * C++ with Classes with args (with constructor) = 1188
+ *
+ */
+#include "stm32l475xx.h"
+#include <cstdint>
+
+class Blink {
+public:
+  Blink(GPIO_TypeDef *port, std::uint8_t pin);
+  // ~Blink();
+
+  void init();
+  void set();
+  void reset();
+  void spin_delay(std::uint32_t delay);
+
+private:
+  GPIO_TypeDef *port;
+  std::uint8_t pin;
+};
+
+Blink::Blink(GPIO_TypeDef *port, std::uint8_t pin) : port(port), pin(pin) {}
+// Blink::~Blink() {}
+
+void Blink::init() {
+  RCC->AHB2ENR |= RCC_AHB2ENR_GPIOAEN;
+  this->port->BRR |= (1 << this->pin); // Reset the pin here
+
+  // Set the mode
+  this->port->MODER &= ~(3 << (this->pin * 2));
+  this->port->MODER |= (1 << (this->pin * 2)); // 01 00 00 00 00 00
+
+  // Check these registers
+  this->port->OTYPER &= ~(1 << this->pin); // set to 0
+  this->port->OSPEEDR &= ~(3 << (this->pin * 2));
+  this->port->PUPDR &= ~(3 << (this->pin * 2));
+}
+
+void Blink::set() {
+  // Set the pin here
+  this->port->BSRR |= (1 << this->pin);
+}
+
+void Blink::reset() {
+  this->port->BRR = (1 << this->pin); // Reset
+}
+
+void Blink::spin_delay(std::uint32_t delay) {
+  while (delay) {
+    __NOP();
+    --delay;
+  }
+}
+
+int main() {
+  Blink blink{GPIOA, 5};
+
+  blink.init();
+  blink.set();
+  blink.spin_delay(1000 * 1000);
+
+  while (1) {
+    blink.reset();
+    blink.spin_delay(1000 * 1000);
+
+    blink.set();
+    blink.spin_delay(1000 * 1000);
+  }
+
+  return 0;
+}
