From 56e87003044d8094ed9a592b4526288a540f56b4 Mon Sep 17 00:00:00 2001
From: crsz20 <cris14.alex@gmail.com>
Date: Thu, 13 Jun 2024 21:49:30 -0500
Subject: [PATCH] Enabled printf()

---
 Firmware/Shifter_System/.cproject           |  14 ++-
 Firmware/Shifter_System/Core/Inc/retarget.h |  32 +++++++
 Firmware/Shifter_System/Core/Src/main.c     |   1 +
 Firmware/Shifter_System/Core/Src/retarget.c | 100 ++++++++++++++++++++
 Firmware/Shifter_System/Program/Src/app.cpp |   9 +-
 5 files changed, 151 insertions(+), 5 deletions(-)
 create mode 100644 Firmware/Shifter_System/Core/Inc/retarget.h
 create mode 100644 Firmware/Shifter_System/Core/Src/retarget.c

diff --git a/Firmware/Shifter_System/.cproject b/Firmware/Shifter_System/.cproject
index a447d42..84cdac5 100644
--- a/Firmware/Shifter_System/.cproject
+++ b/Firmware/Shifter_System/.cproject
@@ -25,6 +25,7 @@
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board.393059222" name="Board" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.target_board" useByScannerDiscovery="false" value="NUCLEO-F446RE" valueType="string"/>
 							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults.556346971" name="Defaults" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.defaults" useByScannerDiscovery="false" value="com.st.stm32cube.ide.common.services.build.inputs.revA.1.0.6 || Debug || true || Executable || com.st.stm32cube.ide.mcu.gnu.managedbuild.option.toolchain.value.workspace || NUCLEO-F446RE || 0 || 0 || arm-none-eabi- || ${gnu_tools_for_stm32_compiler_path} || ../Core/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc | ../Drivers/STM32F4xx_HAL_Driver/Inc/Legacy | ../Drivers/CMSIS/Device/ST/STM32F4xx/Include | ../Drivers/CMSIS/Include ||  ||  || USE_HAL_DRIVER | STM32F446xx ||  || Drivers | Core/Startup | Core ||  ||  || ${workspace_loc:/${ProjName}/STM32F446RETX_FLASH.ld} || true || NonSecure ||  || secure_nsclib.o ||  || None ||  ||  || " valueType="string"/>
 							<option id="com.st.stm32cube.ide.mcu.debug.option.cpuclock.1821070149" name="Cpu clock frequence" superClass="com.st.stm32cube.ide.mcu.debug.option.cpuclock" useByScannerDiscovery="false" value="84" valueType="string"/>
+							<option id="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.nanoprintffloat.385811399" name="Use float with printf from newlib-nano (-u _printf_float)" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.option.nanoprintffloat" useByScannerDiscovery="false" value="true" valueType="boolean"/>
 							<targetPlatform archList="all" binaryParser="org.eclipse.cdt.core.ELF" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform.336488663" isAbstract="false" osList="all" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.targetplatform"/>
 							<builder buildPath="${workspace_loc:/Shifter_System}/Debug" id="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder.589651570" keepEnvironmentInBuildfile="false" managedBuildOn="true" name="Gnu Make Builder" parallelBuildOn="true" parallelizationNumber="optimal" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.builder"/>
 							<tool id="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler.448493510" name="MCU GCC Assembler" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.assembler">
@@ -87,10 +88,19 @@
 							<tool id="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.objcopy.symbolsrec.1431819164" name="MCU Output Converter Motorola S-rec with symbols" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.objcopy.symbolsrec"/>
 						</toolChain>
 					</folderInfo>
+					<fileInfo id="com.st.stm32cube.ide.mcu.gnu.managedbuild.config.exe.debug.285203902.1302876059" name="syscalls.c" rcbsApplicability="disable" resourcePath="Core/Src/syscalls.c" toolsToInvoke="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.c.compiler.2124145833.2145290782">
+						<tool id="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.c.compiler.2124145833.2145290782" name="MCU GCC Compiler" superClass="com.st.stm32cube.ide.mcu.gnu.managedbuild.tool.c.compiler.2124145833"/>
+						<tool customBuildStep="true" id="org.eclipse.cdt.managedbuilder.ui.rcbs.719623083" name="Resource Custom Build Step">
+							<inputType id="org.eclipse.cdt.managedbuilder.ui.rcbs.inputtype.1440616304" name="Resource Custom Build Step Input Type">
+								<additionalInput kind="additionalinputdependency" paths=""/>
+							</inputType>
+							<outputType id="org.eclipse.cdt.managedbuilder.ui.rcbs.outputtype.294120858" name="Resource Custom Build Step Output Type"/>
+						</tool>
+					</fileInfo>
 					<sourceEntries>
-						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Core"/>
+						<entry excluding="Src/syscalls.c" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Core"/>
 						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Drivers"/>
-						<entry flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="Program"/>
+						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Program"/>
 					</sourceEntries>
 				</configuration>
 			</storageModule>
diff --git a/Firmware/Shifter_System/Core/Inc/retarget.h b/Firmware/Shifter_System/Core/Inc/retarget.h
new file mode 100644
index 0000000..d489b39
--- /dev/null
+++ b/Firmware/Shifter_System/Core/Inc/retarget.h
@@ -0,0 +1,32 @@
+// All credit to Carmine Noviello for this code
+// https://github.com/cnoviello/mastering-stm32/blob/master/nucleo-f030R8/system/include/retarget/retarget.h
+
+#ifndef _RETARGET_H__
+#define _RETARGET_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "stm32f4xx_hal.h"
+#include <sys/stat.h>
+
+void RetargetInit(UART_HandleTypeDef *huart);
+int _isatty(int fd);
+int _write(int fd, char* ptr, int len);
+int _close(int fd);
+int _lseek(int fd, int ptr, int dir);
+int _read(int fd, char* ptr, int len);
+int _fstat(int fd, struct stat* st);
+
+// These three functions must be implemented when enabling printf with foating point values
+int _kill(int pid, int sig);
+int _getpid();
+void _exit(int);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif //#ifndef _RETARGET_H__
diff --git a/Firmware/Shifter_System/Core/Src/main.c b/Firmware/Shifter_System/Core/Src/main.c
index 92b6949..0c197f7 100644
--- a/Firmware/Shifter_System/Core/Src/main.c
+++ b/Firmware/Shifter_System/Core/Src/main.c
@@ -24,6 +24,7 @@
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
 #include "../../Program/Src/app.hpp"
+#include "retarget.h"
 
 /* USER CODE END Includes */
 
diff --git a/Firmware/Shifter_System/Core/Src/retarget.c b/Firmware/Shifter_System/Core/Src/retarget.c
new file mode 100644
index 0000000..3e0340c
--- /dev/null
+++ b/Firmware/Shifter_System/Core/Src/retarget.c
@@ -0,0 +1,100 @@
+// All credit to Carmine Noviello for this code
+// https://github.com/cnoviello/mastering-stm32/blob/master/nucleo-f030R8/system/src/retarget/retarget.c
+
+#include <_ansi.h>
+#include <_syslist.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <limits.h>
+#include <signal.h>
+#include <../Inc/retarget.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#if !defined(OS_USE_SEMIHOSTING)
+
+#define STDIN_FILENO  0
+#define STDOUT_FILENO 1
+#define STDERR_FILENO 2
+
+UART_HandleTypeDef *gHuart;
+
+void RetargetInit(UART_HandleTypeDef *huart) {
+  gHuart = huart;
+
+  /* Disable I/O buffering for STDOUT stream, so that
+   * chars are sent out as soon as they are printed. */
+  setvbuf(stdout, NULL, _IONBF, 0);
+}
+
+int _isatty(int fd) {
+  if (fd >= STDIN_FILENO && fd <= STDERR_FILENO)
+    return 1;
+
+  errno = EBADF;
+  return 0;
+}
+
+int _write(int fd, char* ptr, int len) {
+  HAL_StatusTypeDef hstatus;
+
+  if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
+    hstatus = HAL_UART_Transmit(gHuart, (uint8_t *) ptr, len, HAL_MAX_DELAY);
+    if (hstatus == HAL_OK)
+      return len;
+    else
+      return EIO;
+  }
+  errno = EBADF;
+  return -1;
+}
+
+int _close(int fd) {
+  if (fd >= STDIN_FILENO && fd <= STDERR_FILENO)
+    return 0;
+
+  errno = EBADF;
+  return -1;
+}
+
+int _lseek(int fd, int ptr, int dir) {
+  (void) fd;
+  (void) ptr;
+  (void) dir;
+
+  errno = EBADF;
+  return -1;
+}
+
+int _read(int fd, char* ptr, int len) {
+  HAL_StatusTypeDef hstatus;
+
+  if (fd == STDIN_FILENO) {
+    hstatus = HAL_UART_Receive(gHuart, (uint8_t *) ptr, 1, HAL_MAX_DELAY);
+    if (hstatus == HAL_OK)
+      return 1;
+    else
+      return EIO;
+  }
+  errno = EBADF;
+  return -1;
+}
+
+int _fstat(int fd, struct stat* st) {
+  if (fd >= STDIN_FILENO && fd <= STDERR_FILENO) {
+    st->st_mode = S_IFCHR;
+    return 0;
+  }
+
+  errno = EBADF;
+  return 0;
+}
+
+
+int _kill(int pid, int sig) { return 0; }
+int _getpid() { return 0; }
+// Added a forever loop to supress warning: "the 'noreturn' function does return"
+void _exit(int) { for(;;) { } }
+
+#endif //#if !defined(OS_USE_SEMIHOSTING)
diff --git a/Firmware/Shifter_System/Program/Src/app.cpp b/Firmware/Shifter_System/Program/Src/app.cpp
index 70a3ddb..f111cf6 100644
--- a/Firmware/Shifter_System/Program/Src/app.cpp
+++ b/Firmware/Shifter_System/Program/Src/app.cpp
@@ -14,19 +14,22 @@
 // ST HAL Dependencies
 #include "gpio.h"
 
-// 3rd Party Libraryes and Frameworks
+#include "usart.h"
+extern UART_HandleTypeDef huart2;
 
 
 // DFR Custom Dependencies
-
+#include "../../Core/Inc/retarget.h"
 
 
 void cppMain() {
-
+	// Enable `printf()` using USART
+	RetargetInit(&huart2);
 
 
 	for(;;){
 		HAL_GPIO_TogglePin(LD2_GPIO_Port, LD2_Pin);
+		printf("hi\n");
 		HAL_Delay(1000);
 	}
 }