/* 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/list.h>
#include <sos/physmem.h>
#include <hwcore/paging.h>
#include <sos/kmem_vmm.h>
#include <sos/kmalloc.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 */
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++;
}
struct digit
{
struct digit *prev, *next;
char value;
};
/* Representation of a big (positive) integer: Most Significant Digit
(MSD) is the HEAD of the list. Least Significant Digit (LSD) is the
TAIL of the list */
typedef struct digit * big_number_t;
/* Add a new digit after the LSD */
void bn_push_lsd(big_number_t * bn, char value)
{
struct digit *d;
d = (struct digit*) sos_kmalloc(sizeof(struct digit), 0);
SOS_ASSERT_FATAL(d != NULL);
d->value = value;
list_add_tail(*bn, d);
}
/* Add a new digit before the MSD */
void bn_push_msd(big_number_t * bn, char value)
{
struct digit *d;
d = (struct digit*) sos_kmalloc(sizeof(struct digit), 0);
SOS_ASSERT_FATAL(d != NULL);
d->value = value;
list_add_head(*bn, d);
}
/* Construct a big integer from a (machine) integer */
big_number_t bn_new(unsigned long int i)
{
big_number_t retval;
list_init(retval);
do
{
bn_push_msd(&retval, i%10);
i /= 10;
}
while (i != 0);
return retval;
}
/* Create a new big integer from another big integer */
big_number_t bn_copy(const big_number_t bn)
{
big_number_t retval;
int nb_elts;
struct digit *d;
list_init(retval);
list_foreach(bn, d, nb_elts)
{
bn_push_lsd(&retval, d->value);
}
return retval;
}
/* Free the memory used by a big integer */
void bn_del(big_number_t * bn)
{
struct digit *d;
list_collapse(*bn, d)
{
sos_kfree((sos_vaddr_t)d);
}
}
/* Shift left a big integer: bn := bn*10^shift */
void bn_shift(big_number_t *bn, int shift)
{
for ( ; shift > 0 ; shift --)
{
bn_push_lsd(bn, 0);
}
}
/* Dump the big integer in bochs */
void bn_print_bochs(const big_number_t bn)
{
int nb_elts;
const struct digit *d;
if (list_is_empty(bn))
sos_bochs_printf("0");
else
list_foreach(bn, d, nb_elts)
sos_bochs_printf("%d", d->value);
}
/* Dump the big integer on the console */
void bn_print_console(unsigned char row, unsigned char col,
unsigned char attribute,
const big_number_t bn,
int nb_decimals)
{
if (list_is_empty(bn))
sos_x86_videomem_printf(row, col, attribute, "0");
else
{
int nb_elts;
const struct digit *d;
unsigned char x = col;
list_foreach(bn, d, nb_elts)
{
if (nb_elts == 0)
{
sos_x86_videomem_printf(row, x, attribute, "%d.", d->value);
x += 2;
}
else if (nb_elts < nb_decimals)
{
sos_x86_videomem_printf(row, x, attribute, "%d", d->value);
x ++;
}
}
sos_x86_videomem_printf(row, x, attribute, " . 10^{%d} ", nb_elts-1);
}
}
/* Result is the addition of 2 big integers */
big_number_t bn_add (const big_number_t bn1, const big_number_t bn2)
{
big_number_t retval;
const struct digit *d1, *d2;
sos_bool_t bn1_end = FALSE, bn2_end = FALSE;
char carry = 0;
list_init(retval);
d1 = list_get_tail(bn1);
bn1_end = list_is_empty(bn1);
d2 = list_get_tail(bn2);
bn2_end = list_is_empty(bn2);
do
{
if (! bn1_end)
carry += d1->value;
if (! bn2_end)
carry += d2->value;
bn_push_msd(&retval, carry % 10);
carry /= 10;
if (! bn1_end)
d1 = d1->prev;
if (! bn2_end)
d2 = d2->prev;
if (d1 == list_get_tail(bn1))
bn1_end = TRUE;
if (d2 == list_get_tail(bn2))
bn2_end = TRUE;
}
while (!bn1_end || !bn2_end);
if (carry > 0)
{
bn_push_msd(&retval, carry);
}
return retval;
}
/* Result is the multiplication of a big integer by a single digit */
big_number_t bn_muli (const big_number_t bn, char digit)
{
big_number_t retval;
int nb_elts;
char carry = 0;
const struct digit *d;
list_init(retval);
list_foreach_backward(bn, d, nb_elts)
{
carry += d->value * digit;
bn_push_msd(&retval, carry % 10);
carry /= 10;
}
if (carry > 0)
{
bn_push_msd(&retval, carry);
}
return retval;
}
/* Result is the multiplication of 2 big integers */
big_number_t bn_mult(const big_number_t bn1, const big_number_t bn2)
{
int shift = 0;
big_number_t retval;
int nb_elts;
struct digit *d;
list_init(retval);
list_foreach_backward(bn2, d, nb_elts)
{
big_number_t retmult = bn_muli(bn1, d->value);
big_number_t old_retval = retval;
bn_shift(& retmult, shift);
retval = bn_add(old_retval, retmult);
bn_del(& retmult);
bn_del(& old_retval);
shift ++;
}
return retval;
}
/* Result is the factorial of an integer */
big_number_t bn_fact(unsigned long int v)
{
unsigned long int i;
big_number_t retval = bn_new(1);
for (i = 1 ; i <= v ; i++)
{
big_number_t I = bn_new(i);
big_number_t tmp = bn_mult(retval, I);
sos_x86_videomem_printf(4, 0,
SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_LTGREEN,
"%d! = ", (int)i);
bn_print_console(4, 8, SOS_X86_VIDEO_BG_BLUE | SOS_X86_VIDEO_FG_WHITE,
tmp, 55);
bn_del(& I);
bn_del(& retval);
retval = tmp;
}
return retval;
}
void bn_test()
{
big_number_t bn = bn_fact(1000);
sos_bochs_printf("1000! = ");
bn_print_bochs(bn);
sos_bochs_printf("\n");
}
/* The C entry point of our operating system */
void sos_main(unsigned long magic, unsigned long addr)
{
unsigned i;
sos_paddr_t sos_kernel_core_base_paddr, sos_kernel_core_top_paddr;
/* 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);
/* We need a multiboot-compliant boot loader to get the size of the RAM */
if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
{
sos_x86_videomem_putstring(20, 0,
SOS_X86_VIDEO_FG_LTRED
| SOS_X86_VIDEO_BG_BLUE
| SOS_X86_VIDEO_FG_BLINKING,
"I'm not loaded with Grub !");
/* STOP ! */
for (;;)
continue;
}
/*
* Some interrupt handlers
*/
/* Binding some HW interrupts and exceptions to software routines */
sos_irq_set_routine(SOS_IRQ_TIMER,
clk_it);
/*
* Setup physical memory management
*/
/* Multiboot says: "The value returned for upper memory is maximally
the address of the first upper memory hole minus 1 megabyte.". It
also adds: "It is not guaranteed to be this value." aka "YMMV" ;) */
sos_physmem_setup((mbi->mem_upper<<10) + (1<<20),
& sos_kernel_core_base_paddr,
& sos_kernel_core_top_paddr);
/*
* Switch to paged-memory mode
*/
/* Disabling interrupts should seem more correct, but it's not really
necessary at this stage */
if (sos_paging_setup(sos_kernel_core_base_paddr,
sos_kernel_core_top_paddr))
sos_bochs_printf("Could not setup paged memory mode\n");
sos_x86_videomem_printf(2, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Paged-memory mode is activated");
/*
* Setup kernel virtual memory allocator
*/
if (sos_kmem_vmm_setup(sos_kernel_core_base_paddr,
sos_kernel_core_top_paddr,
bootstrap_stack_bottom,
bootstrap_stack_bottom + bootstrap_stack_size))
sos_bochs_printf("Could not setup the Kernel virtual space allocator\n");
if (sos_kmalloc_setup())
sos_bochs_printf("Could not setup the Kmalloc subsystem\n");
/* Run some kmalloc tests */
bn_test();
/*
* Enabling the HW interrupts here, this will make the timer HW
* interrupt call our clk_it handler
*/
asm volatile ("sti\n");
/* An operatig system never ends */
for (;;)
continue;
return;
}
