From fb2c7ecf23013a6e32e0e2418ece75fbdfd61274 Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Sat, 19 Oct 2024 19:47:36 +0200
Subject: [PATCH] feat: add support for newlib

---
 Makefile                           |  13 +++-
 devices/general/startup.c          |   2 +
 devices/stm32h747/linker_script.ld |  23 ++++++
 src/main.c                         |  24 +++++++
 src/syscalls.c                     | 112 +++++++++++++++++++++++++++++
 5 files changed, 171 insertions(+), 3 deletions(-)
 create mode 100644 src/syscalls.c

diff --git a/Makefile b/Makefile
index f6a4588..2d9064a 100644
--- a/Makefile
+++ b/Makefile
@@ -23,9 +23,9 @@ CFLAGS=-I$(INCDIR) \
 				-I$(DEVICEDIR)/$(INCDIR) \
 				-Ilibs/CMSIS_6/CMSIS/Core/Include \
 				-Ilibs/cmsis_device_h7/Include \
-				-mthumb -mcpu=$(CPU) -nostdlib -g \
+				-mthumb -mcpu=$(CPU) --specs=nano.specs -g \
 				-DCORE_CM7
-LDFLAGS=-T$(DEVICEDIR)/linker_script.ld -nostdlib
+LDFLAGS=-T$(DEVICEDIR)/linker_script.ld
 
 CC=arm-none-eabi-gcc
 LD=arm-none-eabi-ld
@@ -33,7 +33,7 @@ OPENOCD=openocd
 
 $(BINDIR)/$(APP): $(OBJS)
 	mkdir -p $(BINDIR)
-	$(LD) $^ -o $@ $(LDFLAGS)
+	$(CC) $^ -o $@ $(CFLAGS) $(LDFLAGS)
 
 $(OBJDIR)/src/%.o: $(SRCDIR)/%.c
 	mkdir -p "$(OBJDIR)/src"
@@ -56,3 +56,10 @@ flash: $(BINDIR)/$(APP)
 
 clean:
 	rm -rf $(OBJDIR) $(BINDIR)
+
+depend: .depend
+.depend: $(SRCS)
+	rm -f "$@"
+	$(CC) $(CFLAGS) -MM $^ > "$@"
+
+include .depend
diff --git a/devices/general/startup.c b/devices/general/startup.c
index f6c0937..2e3de69 100644
--- a/devices/general/startup.c
+++ b/devices/general/startup.c
@@ -3,6 +3,7 @@
 
 extern uint32_t _data_size, _bss_size, _data_loadaddr, _sdata, _sbss;
 void main(void);
+void __libc_init_array();
 
 void reset_handler(void)
 {
@@ -25,5 +26,6 @@ void reset_handler(void)
     bss[i] = 0;
   }
 
+  __libc_init_array();
   main();
 }
diff --git a/devices/stm32h747/linker_script.ld b/devices/stm32h747/linker_script.ld
index cda55f8..2abddc6 100644
--- a/devices/stm32h747/linker_script.ld
+++ b/devices/stm32h747/linker_script.ld
@@ -22,6 +22,27 @@ SECTIONS
     _etext = .;
   } >FLASH
 
+  .preinit_array     :
+  {
+      PROVIDE_HIDDEN (__preinit_array_start = .);
+      KEEP (*(.preinit_array*))
+      PROVIDE_HIDDEN (__preinit_array_end = .);
+  } >FLASH
+  .init_array :
+  {
+      PROVIDE_HIDDEN (__init_array_start = .);
+      KEEP (*(SORT(.init_array.*)))
+      KEEP (*(.init_array*))
+      PROVIDE_HIDDEN (__init_array_end = .);
+  } >FLASH
+  .fini_array :
+  {
+      PROVIDE_HIDDEN (__fini_array_start = .);
+      KEEP (*(SORT(.fini_array.*)))
+      KEEP (*(.fini_array*))
+      PROVIDE_HIDDEN (__fini_array_end = .);
+  } >FLASH
+
   .data :
   {
     . = ALIGN(4);
@@ -40,11 +61,13 @@ SECTIONS
   {
     . = ALIGN(4);
     _sbss = .;
+    __bss_start__ = _sbss;
 
     *(.bss)
 
     . = ALIGN(4);
     _ebss = .;
+    __bss_end__ = _ebss;
   } >SRAM
 
   _bss_size = _ebss - _sbss;
diff --git a/src/main.c b/src/main.c
index f1307c1..5d103e5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,10 +1,27 @@
 #include <stdint.h>
 #include <stm32h747xx.h>
 #include <core_cm7.h>
+#include <stdlib.h>
 
 #define LED1_PIN 12
 #define LED2_PIN 13
 
+void hard_fault_handler() {
+  while(1) {}
+}
+
+void usage_fault_handler() {
+  while(1) {}
+}
+
+void nmi_handler() {
+  while(1) {}
+}
+
+void bus_fault_handler() {
+  while(1) {}
+}
+
 void led_toggle()
 {
   GPIOI->ODR ^= (1 << LED1_PIN);
@@ -33,6 +50,13 @@ void exti15_10_handler(void)
 
 void main()
 {
+  uint32_t *i1 = malloc(sizeof(uint32_t));
+  uint32_t *i2 = malloc(sizeof(uint32_t));
+
+  free(i1);
+
+  uint32_t *i3 = malloc(sizeof(uint32_t));
+
   led_gpio_en();
   led_input();
   led_toggle();
diff --git a/src/syscalls.c b/src/syscalls.c
new file mode 100644
index 0000000..1993682
--- /dev/null
+++ b/src/syscalls.c
@@ -0,0 +1,112 @@
+#include <sys/stat.h>
+#include <sys/times.h>
+#include <errno.h>
+#undef errno
+extern int errno;
+
+void _exit(int exit_code)
+{
+    while (1)
+    {
+
+    }
+}
+
+int _close(int file) {
+  return -1;
+}
+
+char *__env[1] = { 0 };
+char **environ = __env;
+
+int _execve(char *name, char **argv, char **env) {
+  errno = ENOMEM;
+  return -1;
+}
+
+int _fork(void) {
+  errno = EAGAIN;
+  return -1;
+}
+
+
+int _fstat(int file, struct stat *st) {
+  st->st_mode = S_IFCHR;
+  return 0;
+}
+
+int _getpid(void) {
+  return 1;
+}
+
+int _isatty(int file) {
+  return 1;
+}
+
+int _kill(int pid, int sig) {
+  errno = EINVAL;
+  return -1;
+}
+
+int _link(char *old, char *new) {
+  errno = EMLINK;
+  return -1;
+}
+
+int _lseek(int file, int ptr, int dir) {
+  return 0;
+}
+
+int _open(const char *name, int flags, int mode) {
+  return -1;
+}
+
+int _read(int file, char *ptr, int len) {
+  return 0;
+}
+
+register char * stack_ptr asm("sp");
+
+caddr_t _sbrk(int incr) {
+  extern char __bss_end__;		/* Defined by the linker */
+  static char *heap_end;
+  char *prev_heap_end;
+
+  if (heap_end == 0) {
+    heap_end = &__bss_end__;
+  }
+  prev_heap_end = heap_end;
+  if (heap_end + incr > stack_ptr) {
+    while (1)
+    {
+        // Heap and stack collision
+    }
+  }
+
+  heap_end += incr;
+  return (caddr_t) prev_heap_end;
+}
+
+int _stat(char *file, struct stat *st) {
+  st->st_mode = S_IFCHR;
+  return 0;
+}
+
+int _times(struct tms *buf) {
+  return -1;
+}
+
+int _unlink(char *name) {
+  errno = ENOENT;
+  return -1;
+}
+
+int _wait(int *status) {
+  errno = ECHILD;
+  return -1;
+}
+
+int _write(int file, char *ptr, int len) {
+  errno = ENOENT;
+  return -1;
+}
-- 
2.49.0