// ***************** arm_syscalls.c ******************************************
//          SBC-DBG debug monitor implementation for ARMCortex-A9. 
//			
//
// (c) OJSC ELVEES, multicore.ru
//
// *******************************************************************
#include <sys/stat.h>

#define CODE_PRINT 0xf
#define CODE_EXIT 0xe 

int _close(int file) { return -1; }
 
int _fstat(int file, struct stat *st) {
 st->st_mode = S_IFCHR;
 return 0;
}
 
int _isatty(int file) { 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 -1;
}
 
char *heap_end = 0;
caddr_t _sbrk(int incr) {
 extern char heap_low; /* Defined by the linker */
 extern char heap_top; /* Defined by the linker */
 char *prev_heap_end;
 
 if (heap_end == 0) {
  heap_end = &heap_low;
 }
 prev_heap_end = heap_end;
 
 if (heap_end + incr > &heap_top) {
  /* Heap and stack collision */
  return (caddr_t)0;
 }
 
 heap_end += incr;
 return (caddr_t) prev_heap_end;
 }
 

int _write(int file, char *ptr, int len) {
  asm volatile ("mov r0, %0; mov r1, %1;bkpt %2;"
       : /*No Outputs */
       : "r" ((int)ptr), "r" (len),  "i" (CODE_PRINT) /* Inputs */
       : "r0", "r1"
  );

  return len;
 }


void _exit(int rc)
{
  asm volatile ("mov r0, %0; bkpt %1;"
		: /* No Output */
		: "r" (rc), "i" (CODE_EXIT)
		: "r0"
  ); 

  for (;;)
    ;
}