BarinkOS/src/kernel.c

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2.5 KiB
C
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#include "kernel.h"
#include "kterm.h"
/**
* simple delay function
**/
void delay(int t){
volatile int i,j;
for(i=0;i<t;i++)
for(j=0;j<25000;j++)
asm("NOP");
}
void kernel_main (void) {
/** initialize terminal interface */
kterm_init();
/** Wrtite stuff to the screen to test the terminal**/
kterm_writestring("Hello world!\n");
kterm_writestring("We got newline support!\n");
for(;;){
delay(500);
kterm_writestring("We have implemented terminal scrolling!\n");
}
}
/**
* KTerm stuff
**/
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;
}
void kterm_init () {
kterm_row = 0;
kterm_column = 0;
kterm_color = vga_entry_color ( VGA_COLOR_LIGHT_GREY , VGA_COLOR_BLACK);
kterm_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;
kterm_buffer[index] = vga_entry(' ', kterm_color);
}
}
}
void kterm_resetcolor(){
kterm_color = vga_entry_color ( VGA_COLOR_LIGHT_GREY , VGA_COLOR_BLACK);
}
void kterm_setcolor(uint8_t color){
kterm_color = color;
}
void kterm_putat (char c, uint8_t color, size_t x, size_t y ) {
const size_t index = y * VGA_WIDTH + x;
kterm_buffer[index] = vga_entry(c, color);
}
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/**
* With the help from:
* https://whiteheadsoftware.dev/operating-systems-development-for-dummies/
**/
void kterm_scrollup(){
size_t i ;
for(i=0; i < (VGA_WIDTH * VGA_HEIGHT - VGA_WIDTH); i++)
kterm_buffer[i] = kterm_buffer[i+VGA_WIDTH];
for( i=0; i< VGA_WIDTH; i++)
kterm_buffer[(VGA_HEIGHT -1) * VGA_WIDTH + i ] = vga_entry(' ', kterm_color);
}
void kterm_put (char c) {
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if(++kterm_column == VGA_WIDTH || c == '\n' ) {
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kterm_column = 0;
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if(kterm_row == VGA_HEIGHT-1) {
kterm_scrollup();
} else {
kterm_row ++;
}
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}
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if(c == '\n') return;
kterm_putat ( c, kterm_color, kterm_column, kterm_row);
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}
void kterm_write(const char* data, size_t size) {
for(size_t i = 0; i < size; i++){
kterm_put(data[i]);
}
}
void kterm_writestring(const char* data ){
AS_KERNEL();
kterm_write(data, strlen(data));
}