diff options
Diffstat (limited to 'kernel.c')
-rw-r--r-- | kernel.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/kernel.c b/kernel.c new file mode 100644 index 0000000..3e75c7a --- /dev/null +++ b/kernel.c @@ -0,0 +1,100 @@ +#include <stdbool.h> +#include <stddef.h> +#include <stdint.h> + +#if defined(__linux__) +#error "Not your cross compiler stupid!" +#endif + + +#if !defined(__i386__) +#error "not ix86-elf" +#endif + +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_BLUE); + terminal_buffer = (uint16_t*) 0xB80000; + 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) { + 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)); +} + +void kernel_main(void) { + terminal_initialize(); + terminal_writestring("Hello, kernel World!\n"); +} + |