Import code for article1, 2, 3, 4

1 files changed, 152 insertions, 0 deletions

diff --git a/sos-code-article2/sos/main.c b/sos-code-article2/sos/main.c
new file mode 100644
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+++ b/sos-code-article2/sos/main.c
@@ -0,0 +1,152 @@
+/* Copyright (C) 2004  The SOS Team
+   Copyright (C) 1999  Free Software Foundation, Inc.
+
+   This program 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 2
+   of the License, or (at your option) any later version.
+   
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   USA. 
+*/
+
+/* Include definitions of the multiboot standard */
+#include <bootstrap/multiboot.h>
+#include <hwcore/idt.h>
+#include <hwcore/gdt.h>
+#include <hwcore/irq.h>
+#include <hwcore/exception.h>
+#include <hwcore/i8254.h>
+#include <sos/klibc.h>
+#include <sos/assert.h>
+#include <drivers/x86_videomem.h>
+#include <drivers/bochs.h>
+
+
+/* Helper function to display each bits of a 32bits integer on the
+   screen as dark or light carrets */
+static void display_bits(unsigned char row, unsigned char col,
+			 unsigned char attribute,
+			 sos_ui32_t integer)
+{
+  int i;
+  /* Scan each bit of the integer, MSb first */
+  for (i = 31 ; i >= 0 ; i--)
+    {
+      /* Test if bit i of 'integer' is set */
+      int bit_i = (integer & (1 << i));
+      /* Ascii 219 => dark carret, Ascii 177 => light carret */
+      unsigned char ascii_code = bit_i?219:177;
+      sos_x86_videomem_putchar(row, col++,
+			       attribute,
+			       ascii_code);
+    }
+}
+
+
+/* Clock IRQ handler */
+static void clk_it(int intid)
+{
+  static sos_ui32_t clock_count = 0;
+
+  display_bits(0, 48,
+	       SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
+	       clock_count);
+  clock_count++;
+
+}
+
+/* Division by zero exception handler */
+static void divide_ex(int exid)
+{
+  static sos_ui32_t div_count = 0;
+  display_bits(0, 0,
+	       SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
+	       div_count);
+  div_count++;
+}
+
+/* The C entry point of our operating system */
+void sos_main(unsigned long magic, unsigned long addr)
+{
+  unsigned i;
+
+  /* Grub sends us a structure, called multiboot_info_t with a lot of
+     precious informations about the system, see the multiboot
+     documentation for more information. */
+  multiboot_info_t *mbi;
+  mbi = (multiboot_info_t *) addr;
+
+  /* Setup bochs and console, and clear the console */
+  sos_bochs_setup();
+
+  sos_x86_videomem_setup();
+  sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE);
+
+  /* Greetings from SOS */
+  if (magic == MULTIBOOT_BOOTLOADER_MAGIC)
+    /* Loaded with Grub */
+    sos_x86_videomem_printf(1, 0,
+			    SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+			    "Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)",
+			    "SOS", ',',
+			    (unsigned)(mbi->mem_upper >> 10) + 1,
+			    (unsigned)mbi->mem_upper);
+  else
+    /* Not loaded with grub */
+    sos_x86_videomem_printf(1, 0,
+			    SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
+			    "Welcome to SOS");
+
+  sos_bochs_putstring("Message in a bochs\n");
+
+  /* Setup CPU segmentation and IRQ subsystem */
+  sos_gdt_setup();
+  sos_idt_setup();
+
+  /* Setup SOS IRQs and exceptions subsystem */
+  sos_exceptions_setup();
+  sos_irq_setup();
+
+  /* Configure the timer so as to raise the IRQ0 at a 100Hz rate */
+  sos_i8254_set_frequency(100);
+
+
+  /* Binding some HW interrupts and exceptions to software routines */
+  sos_irq_set_routine(SOS_IRQ_TIMER,
+			    clk_it);
+  sos_exception_set_routine(SOS_EXCEPT_DIVIDE_ERROR,
+			    divide_ex);
+  /* Enabling the HW interrupts here, this will make the timer HW
+     interrupt call our clk_it handler */
+  asm volatile ("sti\n");
+
+  /* Raise a rafale of 'division by 0' exceptions. All this code is
+     not really needed (equivalent to a bare "i=1/0;"), except when
+     compiling with -O3: "i=1/0;" is considered dead code with gcc
+     -O3. */
+  i = 10;
+  while (1)
+    {
+      /* Stupid function call to fool gcc optimizations */
+      sos_bochs_printf("i = 1 / %d...\n", i);
+      i = 1 / i;
+    }
+
+  /* Will never print this since the "divide by zero" exception always
+     returns to the faulting instruction (see Intel x86 doc vol 3,
+     section 5.12), thus re-evaluating the "divide-by-zero" exprssion
+     and raising the "divide by zero" exception again and again... */
+  sos_x86_videomem_putstring(2, 0,
+			     SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
+			     "Invisible");
+
+  return;
+}