firmware/src/os/syscalls.c

   1 /***********************************************************************/
   2 /*                                                                     */
   3 /*  SYSCALLS.C:  System Calls                                          */
   4 /*  most of this is from newlib-lpc and a Keil-demo                    */
   5 /*                                                                     */
   6 /*  These are "reentrant functions" as needed by                       */
   7 /*  the WinARM-newlib-config, see newlib-manual.                       */
   8 /*  Collected and modified by Martin Thomas                            */
   9 /*                                                                     */
  10 /***********************************************************************/
  11
  12
  13 #include <stdlib.h>
  14 #include <reent.h>
  15 #include <sys/stat.h>
  16
  17 #include <board.h>
  18
  19 static void my_putc(char c)
  20 {
  21         while (!AT91F_US_TxReady((AT91PS_USART)AT91C_BASE_DBGU));
  22         AT91F_US_PutChar((AT91PS_USART)AT91C_BASE_DBGU, c);
  23 }
  24
  25 static int  my_kbhit( void )
  26 {
  27         if ((AT91F_US_RxReady((AT91PS_USART)AT91C_BASE_DBGU)) == 0) return 0;
  28         else return 1;
  29 }
  30
  31 static char my_getc( void )
  32 {
  33         return AT91F_US_GetChar((AT91PS_USART)AT91C_BASE_DBGU);
  34 }
  35
  36 _ssize_t _read_r(
  37     struct _reent *r,
  38     int file,
  39     void *ptr,
  40     size_t len)
  41 {
  42         char c;
  43         unsigned int  i;
  44         unsigned char *p;
  45
  46         p = (unsigned char*)ptr;
  47
  48         for (i = 0; i < len; i++) {
  49                 // c = uart0Getch();
  50                 // c = uart0GetchW();
  51                 while ( !my_kbhit() ) ;
  52                 c = (char) my_getc();
  53                 if (c == 0x0D) {
  54                         *p='\0';
  55                         break;
  56                 }
  57                 *p++ = c;
  58                 ////// uart0_putc(c);
  59         }
  60         return len - i;
  61 }
  62
  63
  64 _ssize_t _write_r (
  65     struct _reent *r,
  66     int file,
  67     const void *ptr,
  68     size_t len)
  69 {
  70         int i;
  71         const unsigned char *p;
  72
  73         p = (const unsigned char*) ptr;
  74
  75         for (i = 0; i < len; i++) {
  76                 if (*p == '\n' ) my_putc('\r');
  77                 my_putc(*p++);
  78         }
  79
  80         return len;
  81 }
  82
  83
  84 int _close_r(
  85     struct _reent *r,
  86     int file)
  87 {
  88         return 0;
  89 }
  90
  91
  92 _off_t _lseek_r(
  93     struct _reent *r,
  94     int file,
  95     _off_t ptr,
  96     int dir)
  97 {
  98         return (_off_t)0;       /*  Always indicate we are at file beginning.  */
  99 }
 100
 101
 102 int _fstat_r(
 103     struct _reent *r,
 104     int file,
 105     struct stat *st)
 106 {
 107         /*  Always set as character device.                             */
 108         st->st_mode = S_IFCHR;
 109         /* assigned to strong type with implicit        */
 110         /* signed/unsigned conversion.  Required by     */
 111         /* newlib.                                      */
 112
 113         return 0;
 114 }
 115
 116
 117 int isatty(int file); /* avoid warning */
 118
 119 int isatty(int file)
 120 {
 121         return 1;
 122 }
 123
 124
 125 #if 0
 126 static void _exit (int n) {
 127 label:  goto label; /* endless loop */
 128 }
 129 #endif
 130
 131
 132 /* "malloc clue function" from newlib-lpc/Keil-Demo/"generic" */
 133
 134 /**** Locally used variables. ****/
 135 // mt: "cleaner": extern char* end;
 136 extern char end[];              /*  end is set in the linker command    */
 137                                 /* file and is the end of statically    */
 138                                 /* allocated data (thus start of heap). */
 139
 140 static char *heap_ptr;          /* Points to current end of the heap.   */
 141
 142 /************************** _sbrk_r *************************************
 143  * Support function. Adjusts end of heap to provide more memory to
 144  * memory allocator. Simple and dumb with no sanity checks.
 145
 146  *  struct _reent *r -- re-entrancy structure, used by newlib to
 147  *                      support multiple threads of operation.
 148  *  ptrdiff_t nbytes -- number of bytes to add.
 149  *                      Returns pointer to start of new heap area.
 150  *
 151  *  Note:  This implementation is not thread safe (despite taking a
 152  *         _reent structure as a parameter).
 153  *         Since _s_r is not used in the current implementation,
 154  *         the following messages must be suppressed.
 155  */
 156 void * _sbrk_r(
 157     struct _reent *_s_r,
 158     ptrdiff_t nbytes)
 159 {
 160         char  *base;            /*  errno should be set to  ENOMEM on error  */
 161
 162         if (!heap_ptr) {        /*  Initialize if first time through.  */
 163                 heap_ptr = end;
 164         }
 165         base = heap_ptr;        /*  Point to end of heap.  */
 166         heap_ptr += nbytes;     /*  Increase heap.  */
 167
 168         return base;            /*  Return pointer to start of new heap area.  */
 169 }