161 lines
No EOL
4 KiB
C
161 lines
No EOL
4 KiB
C
#include <stdbool.h>
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
|
|
/* Check if the compiler thinks you are targeting the wrong operating system. */
|
|
#if defined(__linux__)
|
|
#error "You are not using a cross-compiler, you will most certainly run into trouble"
|
|
#endif
|
|
|
|
/* This tutorial will only work for the 32-bit ix86 targets. */
|
|
#if !defined(__i386__)
|
|
#error "This tutorial needs to be compiled with a ix86-elf compiler"
|
|
#endif
|
|
|
|
/* Hardware text mode color constants. */
|
|
enum vga_color {
|
|
VGA_COLOR_BLACK = 0,
|
|
VGA_COLOR_BLUE = 1,
|
|
VGA_COLOR_GREEN = 2,
|
|
VGA_COLOR_CYAN = 3,
|
|
VGA_COLOR_RED = 4,
|
|
VGA_COLOR_MAGENTA = 5,
|
|
VGA_COLOR_BROWN = 6,
|
|
VGA_COLOR_LIGHT_GREY = 7,
|
|
VGA_COLOR_DARK_GREY = 8,
|
|
VGA_COLOR_LIGHT_BLUE = 9,
|
|
VGA_COLOR_LIGHT_GREEN = 10,
|
|
VGA_COLOR_LIGHT_CYAN = 11,
|
|
VGA_COLOR_LIGHT_RED = 12,
|
|
VGA_COLOR_LIGHT_MAGENTA = 13,
|
|
VGA_COLOR_LIGHT_BROWN = 14,
|
|
VGA_COLOR_WHITE = 15,
|
|
};
|
|
|
|
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
|
|
{
|
|
return fg | bg << 4;
|
|
}
|
|
|
|
static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
|
|
{
|
|
return (uint16_t) uc | (uint16_t) color << 8;
|
|
}
|
|
|
|
size_t strlen(const char* str)
|
|
{
|
|
size_t len = 0;
|
|
while (str[len])
|
|
len++;
|
|
return len;
|
|
}
|
|
|
|
static const size_t VGA_WIDTH = 80;
|
|
static const size_t VGA_HEIGHT = 25;
|
|
|
|
size_t terminal_row;
|
|
size_t terminal_column;
|
|
uint8_t terminal_color;
|
|
uint16_t* terminal_buffer;
|
|
|
|
void terminal_initialize(void)
|
|
{
|
|
terminal_row = 0;
|
|
terminal_column = 0;
|
|
terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
|
|
terminal_buffer = (uint16_t*) 0xB8000;
|
|
for (size_t y = 0; y < VGA_HEIGHT; y++) {
|
|
for (size_t x = 0; x < VGA_WIDTH; x++) {
|
|
const size_t index = y * VGA_WIDTH + x;
|
|
terminal_buffer[index] = vga_entry(' ', terminal_color);
|
|
}
|
|
}
|
|
}
|
|
|
|
void terminal_setcolor(uint8_t color)
|
|
{
|
|
terminal_color = color;
|
|
}
|
|
|
|
void terminal_putentryat(char c, uint8_t color, size_t x, size_t y)
|
|
{
|
|
const size_t index = y * VGA_WIDTH + x;
|
|
terminal_buffer[index] = vga_entry(c, color);
|
|
}
|
|
|
|
void terminal_putchar(char c)
|
|
{
|
|
if (c == '\n') {
|
|
terminal_column = 0;
|
|
terminal_row++;
|
|
return;
|
|
}
|
|
|
|
terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
|
|
if (++terminal_column == VGA_WIDTH) {
|
|
terminal_column = 0;
|
|
if (++terminal_row == VGA_HEIGHT)
|
|
terminal_row = 0;
|
|
}
|
|
}
|
|
|
|
void terminal_write(const char* data, size_t size)
|
|
{
|
|
for (size_t i = 0; i < size; i++)
|
|
terminal_putchar(data[i]);
|
|
}
|
|
|
|
void terminal_writestring(const char* data)
|
|
{
|
|
terminal_write(data, strlen(data));
|
|
}
|
|
|
|
char* itoa(int value, char* result, int base) {
|
|
// check that the base if valid
|
|
if (base < 2 || base > 36) { *result = '\0'; return result; }
|
|
|
|
char* ptr = result, *ptr1 = result, tmp_char;
|
|
int tmp_value;
|
|
|
|
do {
|
|
tmp_value = value;
|
|
value /= base;
|
|
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
|
|
} while ( value );
|
|
|
|
// Apply negative sign
|
|
if (tmp_value < 0) *ptr++ = '-';
|
|
*ptr-- = '\0';
|
|
while(ptr1 < ptr) {
|
|
tmp_char = *ptr;
|
|
*ptr--= *ptr1;
|
|
*ptr1++ = tmp_char;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
void terminal_writeint(const int data) {
|
|
char result[10];
|
|
terminal_writestring(itoa(data, result, 10));
|
|
}
|
|
|
|
|
|
void kernel_main(void)
|
|
{
|
|
int input[] = {
|
|
106404,140515,142745,120767,79665,54235,127391,72207,70799,79485,103994,129583,132791,95135,121194,129425,64861,123233,132805,87916,111395,126625,113045,61704,65413,145820,75988,74717,115137,85331,86833,86063,85464,139738,103372,101942,52741,77660,112745,103109,106301,141714,74546,55474,106747,140234,60426,145867,144810,94179,101606,77763,139291,104246,148513,126828,64624,139058,85839,86636,62198,137358,76711,87848,141711,114079,71639,95896,104522,61929,72199,142790,137736,123437,91872,127661,111179,51548,83452,91196,117798,84484,75517,83820,97407,89181,71428,72758,73076,109957,50601,74571,65556,129765,80626,126995,73480,71360,103288,85670,0
|
|
};
|
|
/* Initialize terminal interface */
|
|
terminal_initialize();
|
|
|
|
int sum = 0;
|
|
int num;
|
|
int i = 0;
|
|
|
|
while ((num = input[i++]) != 0) {
|
|
sum += (num / 3) - 2;
|
|
}
|
|
|
|
terminal_writestring("result = ");
|
|
terminal_writeint(sum);
|
|
} |