[PATCH 3/4] implement the nuconsole input terminal

[Luc Van Rompaey]

The  nuconsole  input  terminal  works in conjunction with the nusetkey
module to support changing the keyboard keymap.
---
 grub-core/Makefile.core.def        |   6 ++
 grub-core/term/i386/pc/nuconsole.c | 111 +++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)
 create mode 100644 grub-core/term/i386/pc/nuconsole.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 6f9e1f0..31d43f2 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2319,3 +2319,9 @@ module = {
   i386_pc = commands/i386/pc/nusetkey.c;
   enable = i386_pc;
 };
+
+module = {
+  name = nuconsole;
+  i386_pc = term/i386/pc/nuconsole.c;
+  enable = i386_pc;
+};
diff --git a/grub-core/term/i386/pc/nuconsole.c 
b/grub-core/term/i386/pc/nuconsole.c
new file mode 100644
index 0000000..ede33ea
--- /dev/null
+++ b/grub-core/term/i386/pc/nuconsole.c
@@ -0,0 +1,111 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002,2003,2005,2007,2008,2009  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/dl.h>
+#include <grub/machine/memory.h>
+#include <grub/term.h>
+#include <grub/types.h>
+#include <grub/machine/int.h>
+#include <grub/machine/nusetkey.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+/*
+ * grub_nuconsole_getkey - If a character  is  pending,  then  return  it.
+ *                         Otherwise,  return GRUB_TERM_NO_KEY (i.e., -1).
+ *
+ *                         BIOS call 'INT 16H Function 11H' checks whether
+ *                         a character is  pending,  supporting  so-called
+ *                         'extended' key codes.
+ *                         Call this function with:
+ *                            -  %ah = 0x11.
+ *                         When the function returns:
+ *                            -  If a character is pending, then:
+ *                                  -  Zero flag is clear.
+ *                                  -  %ah = keyboard scan code.
+ *                                  -  %al = ASCII character.
+ *                            -  If there is no character pending, then:
+ *                                  -  Zero flag is set.
+ *
+ *                         BIOS  call  'INT  16H  Function  10H'  reads  a
+ *                         character from the keyboard,  again  supporting
+ *                         'extended' key codes.
+ *                         Call this function with:
+ *                            -  %ah = 0x10.
+ *                         When the function returns:
+ *                            -  %ah = keyboard scan code.
+ *                            -  %al = ASCII character.
+ */
+static int
+grub_nuconsole_getkey (struct grub_term_input *term __attribute__ ((unused)))
+{
+  struct grub_bios_int_registers regs;
+
+  /*
+   * Check if a character is pending.
+   */
+  regs.eax = 0x1100;
+  regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
+  grub_bios_interrupt (0x16, &regs);
+  if (regs.flags & GRUB_CPU_INT_FLAGS_ZERO)
+    return GRUB_TERM_NO_KEY;
+
+  /*
+   * Read the character that is pending.
+   */
+  regs.eax = 0x1000;
+  regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
+  grub_bios_interrupt (0x16, &regs);
+
+  /*
+   * Process the key code that was read from the keyboard,  and return the
+   * corresponding GRUB key code.
+   */
+  return grub_nusetkey_xlat (regs.eax);
+}
+
+static const struct grub_machine_bios_data_area *bios_data_area =
+  (struct grub_machine_bios_data_area *) 
GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
+
+/*
+ * grub_nuconsole_getkeystatus - Return the Shift, Ctrl, and Alt  modifier
+ *                               states.
+ */
+static int
+grub_nuconsole_getkeystatus (struct grub_term_input *term __attribute__ 
((unused)))
+{
+  /* conveniently GRUB keystatus is modelled after BIOS one.  */
+  return bios_data_area->keyboard_flag_lower & ~0x80;
+}
+
+static struct grub_term_input grub_nuconsole_term_input =
+  {
+    .name = "nuconsole",
+    .getkey = grub_nuconsole_getkey,
+    .getkeystatus = grub_nuconsole_getkeystatus
+  };
+
+GRUB_MOD_INIT(nuconsole)
+{
+  grub_term_register_input ("nuconsole", &grub_nuconsole_term_input);
+}
+
+GRUB_MOD_FINI(nuconsole)
+{
+  grub_term_unregister_input (&grub_nuconsole_term_input);
+}
-- 
2.1.4