summaryrefslogtreecommitdiff
path: root/sos-code-article5/sos/main.c
diff options
context:
space:
mode:
Diffstat (limited to 'sos-code-article5/sos/main.c')
-rw-r--r--sos-code-article5/sos/main.c450
1 files changed, 450 insertions, 0 deletions
diff --git a/sos-code-article5/sos/main.c b/sos-code-article5/sos/main.c
new file mode 100644
index 0000000..39bb448
--- /dev/null
+++ b/sos-code-article5/sos/main.c
@@ -0,0 +1,450 @@
+/* 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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-18 10:48:49 +0000