syscalls.c

/**
  * \file syscalls_stm32.c
  *
  * Implementation of newlib syscall.
  *
  */

#include "stm32_def.h"
#if defined (  __GNUC__  ) /* GCC CS3 */
  #include <sys/stat.h>
#endif
#include <errno.h>
#undef errno
extern int errno;

extern size_t uart_debug_write(uint8_t *data, uint32_t size);

// Helper macro to mark unused parameters and prevent compiler warnings.
// Appends _UNUSED to the variable name to prevent accidentally using them.
#ifdef UNUSED
#undef UNUSED
#endif
#ifdef __GNUC__
#define UNUSED(x) x ## _UNUSED __attribute__((__unused__))
#else
#define UNUSED(x) x ## _UNUSED
#endif

__attribute__((weak))
caddr_t _sbrk( int incr ) {
  extern char _estack; /* Defined in the linker script */
  extern char _Min_Stack_Size; /* Defined in the linker script */
  extern char _end; /* Defined by the linker */
  static char *heap_end = &_end ;
  char *prev_heap_end = heap_end;

  if (heap_end + incr > (char *)__get_MSP()) {
    /* Heap and stack collision */
    errno = ENOMEM;
    return (caddr_t) -1;
  }
  /* Ensure to keep minimun stack size defined in the linker script */
  if (heap_end + incr >= (char*)(&_estack - &_Min_Stack_Size)) {
    errno = ENOMEM;
    return (caddr_t) -1;
  }

  heap_end += incr ;
  return (caddr_t) prev_heap_end ;
}

__attribute__((weak))
int _close( UNUSED(int file) ) {
  return -1;
}

__attribute__((weak))
int _fstat( UNUSED(int file), struct stat *st ) {
  st->st_mode = S_IFCHR ;
  return 0;
}

__attribute__((weak))
int _isatty( UNUSED(int file) ) {
  return 1;
}

__attribute__((weak))
int _lseek( UNUSED(int file), UNUSED(int ptr), UNUSED(int dir) ) {
  return 0;
}

__attribute__((weak))
int _read( UNUSED(int file), UNUSED(char *ptr), UNUSED(int len) ) {
  return 0;
}

__attribute__((weak))
int _write( UNUSED(int file), char *ptr, int len ) {
#ifdef HAL_UART_MODULE_ENABLED
  return uart_debug_write((uint8_t *)ptr, (uint32_t)len);
#else
  (void)ptr;
  return len;
#endif
}

__attribute__((weak))
void _exit( UNUSED(int status) ) {
  for ( ; ; ) ;
}

__attribute__((weak))
int _kill( UNUSED(int pid), UNUSED(int sig) ) {
  errno = EINVAL;
  return -1;
}

__attribute__((weak))
int _getpid( void ) {
  return 1;
}