Index: /soft/giet_vm/giet_kernel/kernel_utils.c
===================================================================
--- /soft/giet_vm/giet_kernel/kernel_utils.c	(revision 446)
+++ /soft/giet_vm/giet_kernel/kernel_utils.c	(revision 446)
@@ -0,0 +1,171 @@
+///////////////////////////////////////////////////////////////////////////////////
+// File     : kernel_utils.c
+// Date     : 01/11/2014
+// Author   : alain greiner
+// Copyright (c) UPMC-LIP6
+///////////////////////////////////////////////////////////////////////////////////
+
+#include <kernel_utils.h>
+#include <sys_handler.h>
+#include <hard_config.h>
+#include <utils.h>
+#include <stdarg.h>
+
+//////////////////////////////////
+void _printf( char * format, ... ) 
+{
+    va_list ap;
+    va_start(ap, format);
+    unsigned int save_sr;     // to save SR value in critical section
+
+    // get TTY0 lock
+    _sys_tty_get_lock( 0, &save_sr );
+
+printf_text:
+
+    while (*format) 
+    {
+        unsigned int i;
+        for (i = 0 ; format[i] && (format[i] != '%') ; i++);
+        if (i) 
+        {
+            if ( _sys_tty_write( format, i, 0 ) != i ) goto return_error;
+            format += i;
+        }
+        if (*format == '%') 
+        {
+            format++;
+            goto printf_arguments;
+        }
+    }
+
+    // release TTY0 lock
+    _sys_tty_release_lock( 0, &save_sr );
+
+    va_end(ap);
+    return;
+
+printf_arguments:
+
+    {
+        char buf[20];
+        char * pbuf;
+        unsigned int len = 0;
+        static const char HexaTab[] = "0123456789ABCDEF";
+        unsigned int i;
+
+        switch (*format++) 
+        {
+            case ('c'):             /* char conversion */
+            {
+                int val = va_arg( ap, int );
+                len = 1;
+                buf[0] = val;
+                pbuf = &buf[0];
+                break;
+            }
+            case ('d'):             /* 32 bits decimal signed  */
+            {
+                int val = va_arg( ap, int );
+                if (val < 0) 
+                {
+                    val = -val;
+                    if ( _sys_tty_write( "-" , 1, 0 ) != 1 ) goto return_error;
+                }
+                for(i = 0; i < 10; i++) 
+                {
+                    buf[9 - i] = HexaTab[val % 10];
+                    if (!(val /= 10)) break;
+                }
+                len =  i + 1;
+                pbuf = &buf[9 - i];
+                break;
+            }
+            case ('u'):             /* 32 bits decimal unsigned  */
+            {
+                unsigned int val = va_arg( ap, unsigned int );
+                for(i = 0; i < 10; i++) 
+                {
+                    buf[9 - i] = HexaTab[val % 10];
+                    if (!(val /= 10)) break;
+                }
+                len =  i + 1;
+                pbuf = &buf[9 - i];
+                break;
+            }
+            case ('x'):             /* 32 bits hexadecimal unsigned */
+            {
+                unsigned int val = va_arg( ap, unsigned int );
+                if ( _sys_tty_write( "0x" , 2, 0 ) != 2 ) goto return_error;
+                for(i = 0; i < 8; i++) 
+                {
+                    buf[7 - i] = HexaTab[val % 16];
+                    if (!(val /= 16))  break;
+                }
+                len =  i + 1;
+                pbuf = &buf[7 - i];
+                break;
+            }
+            case ('l'):            /* 64 bits hexadecimal unsigned */
+            {
+                unsigned long long val = va_arg( ap, unsigned long long );
+                if ( _sys_tty_write( "0x" , 2, 0 ) != 2 ) goto return_error;
+                for(i = 0; i < 16; i++) 
+                {
+                    buf[15 - i] = HexaTab[val % 16];
+                    if (!(val /= 16))  break;
+                }
+                len =  i + 1;
+                pbuf = &buf[15 - i];
+                break;
+            }
+            case ('s'):             /* string */
+            {
+                char* str = va_arg( ap, char* );
+                while (str[len]) 
+                {
+                    len++;
+                }
+                pbuf = str;
+                break;
+            }
+            default:
+                goto return_error;
+        }
+
+        if ( _sys_tty_write( pbuf, len, 0 ) != len ) goto return_error;
+        
+        goto printf_text;
+    }
+
+return_error:
+
+    {
+        unsigned int procid     = _get_procid();
+        unsigned int x          = (procid >> (Y_WIDTH + P_WIDTH)) & ((1<<X_WIDTH)-1);
+        unsigned int y          = (procid >> P_WIDTH) & ((1<<Y_WIDTH)-1);
+        unsigned int lpid       = procid & ((1<<P_WIDTH)-1);
+
+        _puts("\n\n[GIET ERROR] in _printf() for processor[");
+        _putd( x );
+        _puts(",");
+        _putd( y );
+        _puts(",");
+        _putd( lpid );
+        _puts("]\n");
+
+        // release TTY0 lock
+        _sys_tty_release_lock( 0, &save_sr );
+
+        _exit();
+    }
+}  // end _printf()
+
+// Local Variables:
+// tab-width: 4
+// c-basic-offset: 4
+// c-file-offsets:((innamespace . 0)(inline-open . 0))
+// indent-tabs-mode: nil
+// End:
+// vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4
+
Index: /soft/giet_vm/giet_kernel/kernel_utils.h
===================================================================
--- /soft/giet_vm/giet_kernel/kernel_utils.h	(revision 446)
+++ /soft/giet_vm/giet_kernel/kernel_utils.h	(revision 446)
@@ -0,0 +1,25 @@
+///////////////////////////////////////////////////////////////////////////////////
+// File     : kernel_utils.h
+// Date     : 01/11/2014
+// Author   : alain greiner 
+// Copyright (c) UPMC-LIP6
+///////////////////////////////////////////////////////////////////////////////////
+// The kernel_utils.c and kernel_utils.h files are part of the GIET-VM nano-kernel.
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef _KERNEL_UTILS_H
+#define _KERNEL_UTILS_H
+
+/////////////////////////////////////////
+extern void _printf( char* format, ... );
+
+#endif
+
+// Local Variables:
+// tab-width: 4
+// c-basic-offset: 4
+// c-file-offsets:((innamespace . 0)(inline-open . 0))
+// indent-tabs-mode: nil
+// End:
+// vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4
+