diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/global_descriptor_table.c | 50 | ||||
| -rw-r--r-- | kernel/global_descriptor_table.h | 1 | ||||
| -rw-r--r-- | kernel/interrupt_descriptor_table.h | 8 | ||||
| -rw-r--r-- | kernel/io/keyboard/keyboard_handler.c | 73 | ||||
| -rw-r--r-- | kernel/io/keyboard/keyboard_handler.h | 1 | ||||
| -rw-r--r-- | kernel/io/keyboard/scancode_map.h | 93 | ||||
| -rw-r--r-- | kernel/io/vga/text_mode_diplay.h | 4 | ||||
| -rw-r--r-- | kernel/io/vga/text_mode_display.c | 6 | ||||
| -rw-r--r-- | kernel/io/vga/text_mode_display.h | 5 | ||||
| -rw-r--r-- | kernel/kernel-bootstrap.asm | 45 | ||||
| -rw-r--r-- | kernel/kernel.c | 7 |
11 files changed, 286 insertions, 7 deletions
diff --git a/kernel/global_descriptor_table.c b/kernel/global_descriptor_table.c new file mode 100644 index 0000000..16b99dc --- /dev/null +++ b/kernel/global_descriptor_table.c @@ -0,0 +1,50 @@ +extern void flush_gdt(); + +struct gdt_entry +{ + unsigned short limit_low; + unsigned short base_low; + unsigned char base_middle; + unsigned char access; + unsigned char granularity; + unsigned char base_high; +} __attribute__((packed)); + +struct gdt_ptr +{ + unsigned short limit; + unsigned int base; +} __attribute__((packed)); + +struct gdt_entry gdt[3]; +struct gdt_ptr gdt_pointer; + +void gdt_set_gate(int num, unsigned long base, unsigned long limit, unsigned char access, unsigned char gran) +{ + + gdt[num].base_low = (base & 0xFFFF); + gdt[num].base_middle = (base >> 16) & 0xFF; + gdt[num].base_high = (base >> 24) & 0xFF; + + gdt[num].limit_low = (limit & 0xFFFF); + gdt[num].granularity = ((limit >> 16) & 0x0F); + + gdt[num].granularity |= (gran & 0xF0); + gdt[num].access = access; +} + +void init_gdt() +{ + gdt_pointer.limit = (sizeof(struct gdt_entry) * 3) - 1; + gdt_pointer.base = (unsigned int) &gdt; + + // Values taken from bkerndev + // First GDT segment must be null + gdt_set_gate(0, 0, 0, 0, 0); + // Code segment + gdt_set_gate(1, 0, 0xFFFFFFFF, 0x9A, 0xCF); + // Data segment + gdt_set_gate(2, 0, 0xFFFFFFFF, 0x92, 0xCF); + + flush_gdt(); +}
\ No newline at end of file diff --git a/kernel/global_descriptor_table.h b/kernel/global_descriptor_table.h new file mode 100644 index 0000000..2774cb1 --- /dev/null +++ b/kernel/global_descriptor_table.h @@ -0,0 +1 @@ +void init_gdt();
\ No newline at end of file diff --git a/kernel/interrupt_descriptor_table.h b/kernel/interrupt_descriptor_table.h new file mode 100644 index 0000000..1d0216b --- /dev/null +++ b/kernel/interrupt_descriptor_table.h @@ -0,0 +1,8 @@ +struct idt_entry +{ + unsigned short int offset_lowerbits; + unsigned short int selector; + unsigned char zero; + unsigned char type_attr; + unsigned short int offset_higherbits; +} __attribute__((packed));
\ No newline at end of file diff --git a/kernel/io/keyboard/keyboard_handler.c b/kernel/io/keyboard/keyboard_handler.c new file mode 100644 index 0000000..86a50a7 --- /dev/null +++ b/kernel/io/keyboard/keyboard_handler.c @@ -0,0 +1,73 @@ +#include "../../interrupt_descriptor_table.h" +#include "../vga/text_mode_display.h" +#include "scancode_map.h" + +extern void keyboard_handler(void); +extern char read_port(unsigned short port); +extern void write_port(unsigned short port, unsigned char data); +extern void load_idt(unsigned long *idt_ptr); + +struct idt_entry keyboard_idt[256]; + +void init_keyboard_idt() +{ + unsigned long keyboard_address; + unsigned long idt_address; + unsigned long idt_ptr[2]; + + // Build IDT entry + keyboard_address = (unsigned long) keyboard_handler; + + keyboard_idt[0x21].offset_lowerbits = keyboard_address & 0xffff; + keyboard_idt[0x21].selector = 0x08; // Offset by 0x08 + keyboard_idt[0x21].zero = 0; + keyboard_idt[0x21].type_attr = 0x8E; // Interrupt gate addr + keyboard_idt[0x21].offset_higherbits = (keyboard_address & 0xffff0000) >> 16; + + idt_address = (unsigned long) keyboard_idt; + idt_ptr[0] = (sizeof(struct idt_entry) * 256) + ((idt_address & 0xffff) << 16); + idt_ptr[1] = idt_address >> 16; + + // Init PIC 1 @ 0x20 + write_port(0x20, 0x11); + write_port(0x21, 0x20); + write_port(0x21, 0x00); + write_port(0x21, 0x01); + write_port(0x21, 0xff); + + // PIC 2 @ 0xA0 + write_port(0xA0, 0x11); + write_port(0xA1, 0x28); + write_port(0xA1, 0x00); + write_port(0xA1, 0x01); + write_port(0xA1, 0xff); + + load_idt(idt_ptr); +} + +void init_keyboard_handler() +{ + init_keyboard_idt(); + + write_port(0x21, 0xFD); +} + +int isKeyup(int scancode) +{ + return scancode & 0x80; +} + +void handle_keypress() { + + // Ack the interrupt + write_port(0x20, 0x20); + + unsigned char scancode = read_port(0x60); + + if(!isKeyup(scancode)) + { + char pressed_key = scancode_map[scancode]; + vga_print_raw(pressed_key); + } + +} diff --git a/kernel/io/keyboard/keyboard_handler.h b/kernel/io/keyboard/keyboard_handler.h new file mode 100644 index 0000000..f56f4f2 --- /dev/null +++ b/kernel/io/keyboard/keyboard_handler.h @@ -0,0 +1 @@ +void init_keyboard_handler();
\ No newline at end of file diff --git a/kernel/io/keyboard/scancode_map.h b/kernel/io/keyboard/scancode_map.h new file mode 100644 index 0000000..e48a1f6 --- /dev/null +++ b/kernel/io/keyboard/scancode_map.h @@ -0,0 +1,93 @@ +char scancode_map[128] = +{ + 0xFF, // Keyboard error code + 0, // Esc + '1', + '2', + '3', + '4', + '5', + '6', + '7', + '8', + '9', + '0', + '-', + '=', + '\b', // Backspace + '\t', // Tab + 'q', + 'w', + 'e', + 'r', + 't', + 'y', + 'u', + 'i', + 'o', + 'p', + '[', + ']', + '\n', // Enter + 0, // Ctrl + 'a', + 's', + 'd', + 'f', + 'g', + 'h', + 'j', + 'k', + 'l', + ';', + '\'', + '`', + 0, // Left Shift + '\\', + 'z', + 'x', + 'c', + 'v', + 'b', + 'n', + 'm', + ',', + '.', + '/', + 0, // Right shift + '*', + 0, // Alt + ' ', // Space + 0, // Caps + 0, // F1 ... + 0, + 0, + 0, + 0, + 0, + 0, + 0, + 0, + 0, // F10 + 0, // Numlock + 0, // Scroll lock + 0, // Home + 0, // Up + 0, // PgUp + '-', + 0, // Left + 0, // Numpad 5 + 0, // Right + '+', + 0, // End + 0, // Down + 0, // PgDown + 0, // Ins + 0, // Del + 0, // Alt-Sysrq + 0, // n/a + 0, // n/a + 0, // F11 + 0, // F12 + 0, // Others are undefined +};
\ No newline at end of file diff --git a/kernel/io/vga/text_mode_diplay.h b/kernel/io/vga/text_mode_diplay.h deleted file mode 100644 index 9441925..0000000 --- a/kernel/io/vga/text_mode_diplay.h +++ /dev/null @@ -1,4 +0,0 @@ -void vga_clear_screen(); -void vga_print(char *msg); -void vga_print_ln(char *msg); -void vga_set_text_colour(int foreground, int background);
\ No newline at end of file diff --git a/kernel/io/vga/text_mode_display.c b/kernel/io/vga/text_mode_display.c index 4844524..bfee909 100644 --- a/kernel/io/vga/text_mode_display.c +++ b/kernel/io/vga/text_mode_display.c @@ -39,4 +39,10 @@ void vga_print_ln(char *msg) void vga_set_text_colour(int foreground, int background) { char_attribute_byte = (background << 4) | foreground; +} + +void vga_print_raw(unsigned char byte) +{ + video_ram[cursor_pos++] = byte; + video_ram[cursor_pos++] = char_attribute_byte; }
\ No newline at end of file diff --git a/kernel/io/vga/text_mode_display.h b/kernel/io/vga/text_mode_display.h new file mode 100644 index 0000000..48bae85 --- /dev/null +++ b/kernel/io/vga/text_mode_display.h @@ -0,0 +1,5 @@ +void vga_clear_screen(); +void vga_print(char *msg); +void vga_print_ln(char *msg); +void vga_set_text_colour(int foreground, int background); +void vga_print_raw(unsigned char byte);
\ No newline at end of file diff --git a/kernel/kernel-bootstrap.asm b/kernel/kernel-bootstrap.asm index 9e3b10e..8af3565 100644 --- a/kernel/kernel-bootstrap.asm +++ b/kernel/kernel-bootstrap.asm @@ -7,12 +7,53 @@ dd 0x1BADB002 dd 0x00 dd - (0x1BADB002 + 0x00) ; checksum +global flush_gdt +global read_port +global write_port +global load_idt +global keyboard_handler global start + extern kernel_entrypoint +extern handle_keypress +extern gdt_pointer + +flush_gdt: + lgdt [gdt_pointer] + mov ax, 0x10 + mov ds, ax + mov es, ax + mov fs, ax + mov gs, ax + mov ss, ax + jmp 0x08:flush +flush: + ret + +read_port: + mov edx, [esp + 4] + in al, dx + ret + +write_port: + mov edx, [esp + 4] + mov al, [esp + 4 + 4] + out dx, al + ret + +load_idt: + mov edx, [esp + 4] + lidt [edx] + sti + ret + +keyboard_handler: + call handle_keypress + iretd + - ; call kernel and halt start: - cli ; disable interrups + cli mov esp, stack_space call kernel_entrypoint hlt diff --git a/kernel/kernel.c b/kernel/kernel.c index fa659dc..ab518e6 100644 --- a/kernel/kernel.c +++ b/kernel/kernel.c @@ -1,5 +1,7 @@ -#include "./io/vga/text_mode_diplay.h" +#include "./io/vga/text_mode_display.h" #include "./io/vga/colours.h" +#include "./io/keyboard/keyboard_handler.h" +#include "global_descriptor_table.h" void run_kern_demo() { @@ -92,5 +94,8 @@ void run_kern_demo() void kernel_entrypoint() { + init_gdt(); + init_keyboard_handler(); run_kern_demo(); + while(1); } |