Inclusion of PC386 BSP submitted by Pedro Miguel Da Cruz Neto Romano

<pmcnr@camoes.rnl.ist.utl.pt> and Jose Rufino <ruf@asterix.ist.utl.pt>
of NavIST (http://pandora.ist.utl.pt/).

4 files changed, 847 insertions, 0 deletions

diff --git a/c/src/lib/libbsp/i386/pc386/console/Makefile.in b/c/src/lib/libbsp/i386/pc386/console/Makefile.in
new file mode 100644
index 0000000000..cd5b344be0
--- /dev/null
+++ b/c/src/lib/libbsp/i386/pc386/console/Makefile.in
@@ -0,0 +1,53 @@
+#
+#  $Id$
+#
+
+@SET_MAKE@
+srcdir = @srcdir@
+top_srcdir = @top_srcdir@
+VPATH=@srcdir@
+
+PGM=${ARCH}/console.rel
+
+# C source names, if any, go here -- minus the .c
+C_PIECES=console inch outch printk
+C_FILES=$(C_PIECES:%=%.c)
+C_O_FILES=$(C_PIECES:%=${ARCH}/%.o)
+
+H_FILES=
+
+SRCS=$(C_FILES) $(H_FILES)
+OBJS=$(C_O_FILES)
+
+include $(RTEMS_CUSTOM)
+include $(PROJECT_ROOT)/make/leaf.cfg
+
+#
+# (OPTIONAL) Add local stuff here using +=
+#
+
+DEFINES  +=
+CPPFLAGS +=
+CFLAGS   +=
+
+LD_PATHS  +=
+LD_LIBS   +=
+LDFLAGS   +=
+
+#
+# Add your list of files to delete here.  The config files
+#  already know how to delete some stuff, so you may want
+#  to just run 'make clean' first to see what gets missed.
+#  'make clobber' already includes 'make clean'
+#
+
+CLEAN_ADDITIONS +=
+CLOBBER_ADDITIONS +=
+
+${PGM}: ${SRCS} ${OBJS}
+	$(make-rel)
+
+all:	${ARCH} $(SRCS) $(PGM)
+
+# the .rel file built here will be put into libbsp.a by ../wrapup/Makefile
+install:  all
diff --git a/c/src/lib/libbsp/i386/pc386/console/console.c b/c/src/lib/libbsp/i386/pc386/console/console.c
new file mode 100644
index 0000000000..220b56f4a4
--- /dev/null
+++ b/c/src/lib/libbsp/i386/pc386/console/console.c
@@ -0,0 +1,250 @@
+/*-------------------------------------------------------------------------+
+| console.c v1.1 - PC386 BSP - 1997/08/07
++--------------------------------------------------------------------------+
+| This file contains the PC386 console I/O package.
++--------------------------------------------------------------------------+
+| (C) Copyright 1997 -
+| - NavIST Group - Real-Time Distributed Systems and Industrial Automation
+|
+| http://pandora.ist.utl.pt
+|
+| Instituto Superior Tecnico * Lisboa * PORTUGAL
++--------------------------------------------------------------------------+
+| Disclaimer:
+|
+| This file is provided "AS IS" without warranty of any kind, either
+| expressed or implied.
++--------------------------------------------------------------------------+
+| This code is based on:
+|   console.c,v 1.4 1995/12/19 20:07:23 joel Exp - go32 BSP
+| With the following copyright notice:
+| **************************************************************************
+| * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.                      *
+| * On-Line Applications Research Corporation (OAR).                       *
+| * All rights assigned to U.S. Government, 1994.                          *
+| *                                                                        *
+| * This material may be reproduced by or for the U.S. Government pursuant *
+| * to the copyright license under the clause at DFARS 252.227-7013.  This *
+| * notice must appear in all copies of this file and its derivatives.     *
+| **************************************************************************
++--------------------------------------------------------------------------*/
+
+
+#include <stdlib.h>
+
+#include <bsp.h>
+#include <irq.h>
+#include <rtems/libio.h>
+
+/*-------------------------------------------------------------------------+
+| Constants
++--------------------------------------------------------------------------*/
+#define KEYBOARD_IRQ  0x01  /* Keyboard IRQ. */
+
+
+/*-------------------------------------------------------------------------+
+| External Prototypes
++--------------------------------------------------------------------------*/
+extern rtems_isr _IBMPC_keyboard_isr(rtems_vector_number);
+       /* keyboard (IRQ 0x01) Interrupt Service Routine (defined in 'inch.c') */
+
+
+/*-------------------------------------------------------------------------+
+| Functions
++--------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------------+
+|         Function: console_cleanup
+|      Description: This routine is called at exit to clean up the console
+|                   hardware. 
+| Global Variables: None.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+void
+console_cleanup(void)
+{
+  /* nothing */
+} /* console_cleanup */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: is_character_ready
+|      Description: Check if a character is available for input, and if so
+|                   return it.
+| Global Variables: None.
+|        Arguments: c - character read if available, otherwise unchanged.
+|          Returns: TRUE if there was a character available for input,
+|                   FALSE otherwise. 
++--------------------------------------------------------------------------*/
+rtems_boolean
+is_character_ready(char *c)
+{
+  return (_IBMPC_chrdy(c) ? TRUE : FALSE);
+} /* is_character_ready */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: inbyte
+|      Description: Read a character from the console (keyboard).
+| Global Variables: None.
+|        Arguments: None.
+|          Returns: Caracter read from the console. 
++--------------------------------------------------------------------------*/
+unsigned char
+inbyte(void)
+{
+  char c = _IBMPC_inch();
+
+  /* Echo character to screen */
+  _IBMPC_outch(c);
+  if (c == '\r')
+    _IBMPC_outch('\n');  /* CR = CR + LF */
+
+  return c;
+} /* inbyte */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: outbyte
+|      Description: Write a character to the console (display).
+| Global Variables: None.
+|        Arguments: Character to be written.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+void
+outbyte(char c)
+{
+  _IBMPC_outch(c);
+} /* outbyte */
+
+
+/*-------------------------------------------------------------------------+
+| Console device driver INITIALIZE entry point.
++--------------------------------------------------------------------------+
+| Initilizes the I/O console (keyboard + VGA display) driver.
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_initialize(rtems_device_major_number major,
+                   rtems_device_minor_number minor,
+                   void                      *arg)
+{
+  rtems_status_code status;
+
+  /* Initialize video */
+  _IBMPC_initVideo();
+
+  /* Install keyboard interrupt handler */
+  status = PC386_installRtemsIrqHandler(KEYBOARD_IRQ, _IBMPC_keyboard_isr);
+
+  if (status != RTEMS_SUCCESSFUL)
+  {
+    printk("Error installing keyboard interrupt handler!\n");
+    rtems_fatal_error_occurred(status);
+  }
+
+  status =
+    rtems_io_register_name("/dev/console", major, (rtems_device_minor_number)0);
+ 
+  if (status != RTEMS_SUCCESSFUL)
+  {
+    printk("Error registering console device!\n");
+    rtems_fatal_error_occurred(status);
+  }
+ 
+  atexit(console_cleanup);
+
+  return RTEMS_SUCCESSFUL;
+} /* console_initialize */
+
+
+/*-------------------------------------------------------------------------+
+| Console device driver OPEN entry point
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_open(rtems_device_major_number major,
+             rtems_device_minor_number minor,
+             void                      *arg)
+{
+  return RTEMS_SUCCESSFUL;
+} /* console_open */
+
+
+/*-------------------------------------------------------------------------+
+| Console device driver CLOSE entry point
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_close(rtems_device_major_number major,
+              rtems_device_minor_number minor,
+              void                      *arg)
+{
+  return RTEMS_SUCCESSFUL;
+} /* console_close */
+
+ 
+/*-------------------------------------------------------------------------+
+| Console device driver READ entry point.
++--------------------------------------------------------------------------+
+| Read characters from the I/O console. We only have stdin.
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_read(rtems_device_major_number major,
+             rtems_device_minor_number minor,
+             void                      *arg)
+{
+  rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
+  char                  *buffer  = rw_args->buffer;
+  int            count, maximum  = rw_args->count;
+ 
+  for (count = 0; count < maximum; count++)
+  {
+    buffer[count] = inbyte();
+    if (buffer[count] == '\n' || buffer[count] == '\r')
+    {
+      /* What if this goes past the end of the buffer?  We're hosed. [bhc] */
+      buffer[count++]  = '\n';
+      buffer[count]    = '\0';
+      break;
+    }
+  }
+ 
+  rw_args->bytes_moved = count;
+  return ((count >= 0) ? RTEMS_SUCCESSFUL : RTEMS_UNSATISFIED);
+} /* console_read */
+ 
+
+/*-------------------------------------------------------------------------+
+| Console device driver WRITE entry point.
++--------------------------------------------------------------------------+
+| Write characters to the I/O console. Stderr and stdout are the same.
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_write(rtems_device_major_number major,
+              rtems_device_minor_number minor,
+              void                    * arg)
+{
+  rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
+  char                  *buffer  = rw_args->buffer;
+  int            count, maximum  = rw_args->count;
+ 
+  for (count = 0; count < maximum; count++)
+  {
+    outbyte(buffer[count]);
+    if (buffer[count] == '\n')
+      outbyte('\r');            /* LF = LF + CR */
+  }
+
+  rw_args->bytes_moved = maximum;
+  return RTEMS_SUCCESSFUL;
+} /* console_write */
+
+
+/*-------------------------------------------------------------------------+
+| Console device driver CONTROL entry point
++--------------------------------------------------------------------------*/
+rtems_device_driver
+console_control(rtems_device_major_number major,
+                rtems_device_minor_number minor,
+                void                      *arg)
+{
+  return RTEMS_SUCCESSFUL;
+} /* console_control */
diff --git a/c/src/lib/libbsp/i386/pc386/console/inch.c b/c/src/lib/libbsp/i386/pc386/console/inch.c
new file mode 100644
index 0000000000..e87e45728c
--- /dev/null
+++ b/c/src/lib/libbsp/i386/pc386/console/inch.c
@@ -0,0 +1,260 @@
+/*-------------------------------------------------------------------------+
+| inch.c v1.1 - PC386 BSP - 1997/08/07
++--------------------------------------------------------------------------+
+| (C) Copyright 1997 -
+| - NavIST Group - Real-Time Distributed Systems and Industrial Automation
+|
+| http://pandora.ist.utl.pt
+|
+| Instituto Superior Tecnico * Lisboa * PORTUGAL
++--------------------------------------------------------------------------+
+| Disclaimer:
+|
+| This file is provided "AS IS" without warranty of any kind, either
+| expressed or implied.
++--------------------------------------------------------------------------+
+| This code is based on:
+|   inch.c,v 1.3 1995/12/19 20:07:25 joel Exp - go32 BSP
+| With the following copyright notice:
+| **************************************************************************
+| * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.                      *
+| * On-Line Applications Research Corporation (OAR).                       *
+| * All rights assigned to U.S. Government, 1994.                          *
+| *                                                                        *
+| * This material may be reproduced by or for the U.S. Government pursuant *
+| * to the copyright license under the clause at DFARS 252.227-7013.  This *
+| * notice must appear in all copies of this file and its derivatives.     *
+| **************************************************************************
++--------------------------------------------------------------------------*/
+
+#include <bsp.h>
+#include <irq.h>
+
+/*-------------------------------------------------------------------------+
+| Constants
++--------------------------------------------------------------------------*/
+#define KBD_CTL      0x61  /* -------------------------------- */
+#define KBD_DATA     0x60  /* Ports for PC keyboard controller */
+#define KBD_STATUS   0x64  /* -------------------------------- */
+
+#define KBD_BUF_SIZE 256
+
+/*-------------------------------------------------------------------------+
+| Global Variables
++--------------------------------------------------------------------------*/
+static char key_map[] =
+{
+  0,033,'1','2','3','4','5','6','7','8','9','0','-','=','\b','\t',
+  'q','w','e','r','t','y','u','i','o','p','[',']',015,0x80,
+  'a','s','d','f','g','h','j','k','l',';',047,0140,0x80,
+  0134,'z','x','c','v','b','n','m',',','.','/',0x80,
+  '*',0x80,' ',0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,
+  0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,
+  0x80,0x80,0x80,'0',0177
+}; /* Keyboard scancode -> character map with no modifiers.       */
+
+static char shift_map[] =
+{
+  0,033,'!','@','#','$','%','^','&','*','(',')','_','+','\b','\t',
+  'Q','W','E','R','T','Y','U','I','O','P','{','}',015,0x80,
+  'A','S','D','F','G','H','J','K','L',':',042,'~',0x80,
+  '|','Z','X','C','V','B','N','M','<','>','?',0x80,
+  '*',0x80,' ',0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,
+  0x80,0x80,0x80,0x80,'7','8','9',0x80,'4','5','6',0x80,
+  '1','2','3','0',177
+}; /* Keyboard scancode -> character map with SHIFT key modifier. */ 
+
+static char             kbd_buffer[KBD_BUF_SIZE];
+static rtems_unsigned16 kbd_first = 0;
+static rtems_unsigned16 kbd_last  = 0;
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_scankey
+|      Description: This function can be called during a poll for input, or by
+|                   an ISR. Basically any time you want to process a keypress.
+| Global Variables: key_map, shift_map.
+|        Arguments: outChar - character read in case of a valid reading,
+|                   otherwise unchanged.
+|          Returns: TRUE in case a valid character has been read,
+|                   FALSE otherwise.
++--------------------------------------------------------------------------*/
+rtems_boolean
+_IBMPC_scankey(char *outChar)
+{
+  unsigned char inChar;
+  static int alt_pressed   = 0;
+  static int ctrl_pressed  = 0;
+  static int shift_pressed = 0;
+  static int caps_pressed  = 0;
+  static int extended      = 0;
+
+  *outChar = NULL; /* default value if we return FALSE */
+
+  /* Read keyboard controller, toggle enable */
+  inport_byte(KBD_CTL, inChar);
+  outport_byte(KBD_CTL, inChar & ~0x80);
+  outport_byte(KBD_CTL, inChar | 0x80);
+  outport_byte(KBD_CTL, inChar & ~0x80);
+
+  /* See if it has data */
+  inport_byte(KBD_STATUS, inChar);
+  if ((inChar & 0x01) == 0)
+    return FALSE;
+
+  /* Read the data.  Handle nonsense with shift, control, etc. */
+  inport_byte(KBD_DATA, inChar);
+
+  if (extended)
+    extended--;
+
+  switch (inChar)
+  {
+    case 0xe0:
+      extended = 2;
+      return FALSE;
+      break;
+
+    case 0x38:
+      alt_pressed = 1;
+      return FALSE;
+      break;
+    case 0xb8:
+      alt_pressed = 0;
+      return FALSE;
+      break;
+
+    case 0x1d:
+      ctrl_pressed = 1;
+      return FALSE;
+      break;
+    case 0x9d:
+      ctrl_pressed = 0;
+      return FALSE;
+      break;
+
+    case 0x2a:
+      if (extended)
+        return FALSE;
+    case 0x36:
+      shift_pressed = 1;
+      return FALSE;
+      break;
+    case 0xaa:
+      if (extended)
+        return FALSE;
+    case 0xb6:
+      shift_pressed = 0;
+      return FALSE;
+      break;
+
+    case 0x3a:
+      caps_pressed = 1;
+      return FALSE;
+      break;
+    case 0xba:
+      caps_pressed = 0;
+      return FALSE;
+      break;
+
+    case 0x53:
+      if (ctrl_pressed && alt_pressed) 
+        rtemsReboot(); /* ctrl+alt+del -> reboot */
+      break;
+
+    /*
+     * Ignore unrecognized keys--usually arrow and such
+     */
+    default:
+      if ((inChar & 0x80) || (inChar > 0x39))
+      /* High-bit on means key is being released, not pressed */
+        return FALSE;
+      break;
+  } /* switch */
+
+  /* Strip high bit, look up in our map */
+  inChar &= 0x7f;
+  if (ctrl_pressed)
+  {
+    *outChar = key_map[inChar];
+    *outChar &= 037;
+  }
+  else
+  {
+    *outChar = shift_pressed ? shift_map[inChar] : key_map[inChar];
+    if (caps_pressed)
+    {
+      if (*outChar >= 'A' && *outChar <= 'Z')
+        *outChar += 'a' - 'A';
+      else if (*outChar >= 'a' && *outChar <= 'z')
+        *outChar -= 'a' - 'A';
+    }
+  }
+
+  return TRUE;
+} /* _IBMPC_scankey */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_keyboard_isr
+|      Description: Interrupt Service Routine for keyboard (0x01) IRQ.
+| Global Variables: kbd_buffer, kbd_first, kbd_last.
+|        Arguments: vector - standard RTEMS argument - see documentation.
+|          Returns: standard return value - see documentation.
++--------------------------------------------------------------------------*/
+rtems_isr
+_IBMPC_keyboard_isr(rtems_vector_number vector)
+{
+  if (_IBMPC_scankey(&kbd_buffer[kbd_last]))
+  {
+    /* Got one; save it if there is enough room in buffer. */
+    unsigned int next = (kbd_last + 1) % KBD_BUF_SIZE;
+
+    if (next != kbd_first)
+      kbd_last = next;
+  }
+
+  PC386_ackIrq(vector - PC386_IRQ_VECTOR_BASE); /* Mark interrupt as handled. */
+} /* _IBMPC_keyboard_isr */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_chrdy
+|      Description: Check keyboard ISR buffer and return character if not empty.
+| Global Variables: kbd_buffer, kbd_first, kbd_last.
+|        Arguments: c - character read if keyboard buffer not empty, otherwise
+|                   unchanged.
+|          Returns: TRUE if keyboard buffer not empty, FALSE otherwise.
++--------------------------------------------------------------------------*/
+rtems_boolean
+_IBMPC_chrdy(char *c)
+{
+  /* Check buffer our ISR builds */
+  if (kbd_first != kbd_last)
+  {
+    *c = kbd_buffer[kbd_first];
+
+    kbd_first = (kbd_first + 1) % KBD_BUF_SIZE;
+    return TRUE;
+  }
+  else
+    return FALSE;
+} /* _IBMPC_chrdy */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_inch
+|      Description: Poll keyboard until a character is ready and return it.
+| Global Variables: None.
+|        Arguments: None.
+|          Returns: character read from keyboard.
++--------------------------------------------------------------------------*/
+char
+_IBMPC_inch(void)
+{
+    char c;
+    while (!_IBMPC_chrdy(&c))
+      continue;
+
+    return c;
+} /* _IBMPC_inch */
diff --git a/c/src/lib/libbsp/i386/pc386/console/outch.c b/c/src/lib/libbsp/i386/pc386/console/outch.c
new file mode 100644
index 0000000000..a7ee806ee4
--- /dev/null
+++ b/c/src/lib/libbsp/i386/pc386/console/outch.c
@@ -0,0 +1,284 @@
+/*-------------------------------------------------------------------------+
+| outch.c v1.1 - PC386 BSP - 1997/08/07
++--------------------------------------------------------------------------+
+| (C) Copyright 1997 -
+| - NavIST Group - Real-Time Distributed Systems and Industrial Automation
+|
+| http://pandora.ist.utl.pt
+|
+| Instituto Superior Tecnico * Lisboa * PORTUGAL
++--------------------------------------------------------------------------+
+| Disclaimer:
+|
+| This file is provided "AS IS" without warranty of any kind, either
+| expressed or implied.
++--------------------------------------------------------------------------+
+| This code is based on:
+|   outch.c,v 1.4 1995/12/19 20:07:27 joel Exp - go32 BSP
+| With the following copyright notice:
+| **************************************************************************
+| * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.                      *
+| * On-Line Applications Research Corporation (OAR).                       *
+| * All rights assigned to U.S. Government, 1994.                          *
+| *                                                                        *
+| * This material may be reproduced by or for the U.S. Government pursuant *
+| * to the copyright license under the clause at DFARS 252.227-7013.  This *
+| * notice must appear in all copies of this file and its derivatives.     *
+| **************************************************************************
++--------------------------------------------------------------------------*/
+
+
+#include <bsp.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+/*-------------------------------------------------------------------------+
+| Constants
++--------------------------------------------------------------------------*/
+#define DISPLAY_CELL_COUNT (MAX_ROW * MAX_COL)
+                                       /* Number of display cells.            */
+#define TABSIZE 4                      /* Number of spaces for TAB (\t) char. */
+#define	WHITE	0x0700                 /* White on Black background colour.   */
+#define BLANK   (WHITE | ' ')          /* Blank character.                    */
+
+
+/*-------------------------------------------------------------------------+
+| Global Variables
++--------------------------------------------------------------------------*/
+static rtems_unsigned16 *videoRam    = TVRAM;
+                           /* Physical address of start of video text memory. */
+static rtems_unsigned16 *videoRamPtr = TVRAM;
+                           /* Pointer for current output position in display. */
+static rtems_unsigned8  videoRows = MAX_ROW; /* Number of rows in display.    */
+static rtems_unsigned8  videoCols = MAX_COL; /* Number of columns in display. */
+static rtems_unsigned8  cursRow   = 0;       /* Current cursor row.           */
+static rtems_unsigned8  cursCol   = 0;       /* Current cursor column.        */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: setHardwareCursorPos
+|      Description: Set hardware video cursor at given offset into video RAM. 
+| Global Variables: None.
+|        Arguments: videoCursor - Offset into video memory.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+setHardwareCursorPos(rtems_unsigned16 videoCursor)
+{
+  outport_byte(GDC_REG_PORT, 0xe);
+  outport_byte(GDC_VAL_PORT, (videoCursor >> 8) & 0xff);
+  outport_byte(GDC_REG_PORT, 0xf);
+  outport_byte(GDC_VAL_PORT, videoCursor & 0xff);
+} /* setHardwareCursorPos */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: updateVideoRamPtr
+|      Description: Updates value of global variable "videoRamPtr" based on
+|                   current window's cursor position. 
+| Global Variables: videoRamPtr, cursRow, cursCol.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+updateVideoRamPtr(void)
+{
+  videoRamPtr = videoRam + cursRow * videoCols + cursCol;
+} /* updateVideoRamPtr */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: scrollUp
+|      Description: Scrolls display up n lines.
+| Global Variables: None.
+|        Arguments: lines - number of lines to scroll.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static void
+scrollUp(rtems_unsigned8 lines)
+{
+  rtems_unsigned16 blankCount;
+                        /* Number of blank display cells on bottom of window. */
+  rtems_unsigned16 *ptrDst, *ptrSrc;
+               /* Source and destination pointers for memory copy operations. */
+
+  if (lines < videoRows)  /* Move window's contents up. */
+  {
+    rtems_unsigned16 nonBlankCount;
+       /* Number of non-blank cells on upper part of display (total - blank). */
+
+    blankCount = lines * videoCols;
+    nonBlankCount = DISPLAY_CELL_COUNT - blankCount;
+    ptrSrc = videoRam + blankCount;
+    ptrDst = videoRam; 
+
+    while(nonBlankCount--)
+      *ptrDst++ = *ptrSrc++;
+  }
+  else                    /* Clear the whole display.   */
+  {
+    blankCount = DISPLAY_CELL_COUNT;
+    ptrDst = videoRam;
+  }
+
+  /* Fill bottom with blanks. */
+  while (blankCount-- > 0)
+    *ptrDst++ = BLANK;
+} /* scrollUp */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: printCHAR
+|      Description: Print printable character to display.
+| Global Variables: videoRamPtr, cursRow, cursCol.
+|        Arguments: c - character to write to display.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static void
+printCHAR(char c)
+{
+  *videoRamPtr++ = c | WHITE;
+  cursCol++;
+  if (cursCol == videoCols)
+  {
+    cursCol = 0;
+    cursRow++;
+    if (cursRow == videoRows)
+    {
+      cursRow--;
+      scrollUp(1);
+      videoRamPtr -= videoCols;
+    }
+  }
+} /* printCHAR */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: printBS
+|      Description: Print BS (BackSpace - '\b') character to display.
+| Global Variables: videoRamPtr, cursRow, cursCol.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+printBS(void)
+{
+  /* Move cursor back one cell. */
+  if (cursCol > 0)
+    cursCol--;
+  else if (cursRow > 0)
+  {
+    cursRow--;
+    cursCol = videoCols - 1;
+  }
+  else
+    return;
+
+  /* Write a whitespace. */
+  *(--videoRamPtr) = BLANK;
+} /* printBS */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: printHT
+|      Description: Print HT (Horizontal Tab - '\t') character to display.
+| Global Variables: cursCol.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+printHT(void)
+{
+  do
+    printCHAR(' ');
+  while (cursCol % TABSIZE);
+} /* printHT */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: printLF
+|      Description: Print LF (Line Feed  - '\n') character to display.
+| Global Variables: cursRow.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+printLF(void)
+{
+  cursRow++;
+  if (cursRow == videoRows)
+  {
+    cursRow--;
+    scrollUp(1);
+  }
+  updateVideoRamPtr();
+} /* printLF */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: printCR
+|      Description: Print CR (Carriage Return - '\r') to display.
+| Global Variables: cursCol.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static inline void
+printCR(void)
+{
+  cursCol = 0;
+  updateVideoRamPtr();
+} /* printCR */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: consPutc
+|      Description: Print a character to display at current position.
+| Global Variables: videoRamPtr, videoRam.
+|        Arguments: c - character to write to display.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+static void
+consPutc(char c)
+{
+  switch (c)
+  {
+    case '\b': printBS();    break;
+    case '\t': printHT();    break;
+    case '\n': printLF();    break;
+    case '\r': printCR();    break;
+    default:   printCHAR(c); break;
+  } /* switch */
+
+  setHardwareCursorPos(videoRamPtr - videoRam);
+                                           /* At current offset into videoRam */
+} /* consPutc */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_outch
+|      Description: Higher level (console) interface to consPutc.
+| Global Variables: None.
+|        Arguments: c - character to write to console.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+void
+_IBMPC_outch(char c)
+{
+  consPutc(c);
+} /* _IBMPC_outch */
+
+
+/*-------------------------------------------------------------------------+
+|         Function: _IBMPC_initVideo
+|      Description: Video system initialization. Hook for any early setup.
+| Global Variables: videoRows.
+|        Arguments: None.
+|          Returns: Nothing. 
++--------------------------------------------------------------------------*/
+void
+_IBMPC_initVideo(void)
+{
+  scrollUp(videoRows);     /* Clear entire screen         */
+  setHardwareCursorPos(0); /* Cursor at upper left corner */
+} /* _IBMPC_initVideo */