Add VGA code to vga_drv

vga_drv/main.c

@@ -1,3 +1,9 @@
-int main() {
+#include <grub/text_fb_info.h>
 
+int main() {
+  text_fb_info info;
+  info.address=map_phys((void*)0xB8000,10);
+  info.width=80;
+  info.height=25;
+  vga_init(info);
 }

vga_drv/ports.c

@@ -0,0 +1,31 @@
+#include <stdint.h>
+
+uint8_t port_byte_in(uint16_t port) {
+  uint8_t result;
+  asm("in %%dx, %%al":"=a"(result):"d"(port));
+  return result;
+}
+
+void port_byte_out(uint16_t port,uint8_t data) {
+  asm("out %%al, %%dx":: "a"(data),"d"(port));
+}
+
+uint16_t port_word_in(uint16_t port) {
+  uint16_t result;
+  asm("in %%dx, %%ax":"=a"(result):"d"(port));
+  return result;
+}
+
+void port_word_out(uint16_t port,uint16_t data) {
+  asm("out %%ax, %%dx":: "a" (data), "d" (port));
+}
+
+uint32_t port_long_in(uint16_t port) {
+  uint32_t result;
+  asm("inl %%dx, %%eax":"=a"(result):"d"(port));
+  return result;
+}
+
+void port_long_out(uint16_t port,uint32_t data) {
+  asm("outl %%eax, %%dx":: "a" (data), "d" (port));
+}

vga_drv/ports.h

@@ -0,0 +1,12 @@
+#ifndef PORTS_H
+#define PORTS_H
+
+#include <stdint.h>
+
+uint8_t port_byte_in(uint16_t port);
+void port_byte_out(uint16_t port,uint8_t data);
+uint16_t port_word_in(uint16_t port);
+void port_word_out(uint16_t port,uint16_t data);
+uint32_t port_long_in(uint16_t port);
+void port_long_out(uint16_t port,uint32_t data);
+#endif

vga_drv/vga.c

@@ -0,0 +1,91 @@
+#include <grub/text_fb_info.h>
+#include "vga.h"
+#include "ports.h"
+#include <string.h>
+#include <stddef.h>
+#define xy_to_indx(x,y) ((x+(y*width))*2)
+static char* screen;
+static int width;
+static int height;
+static int x;
+static int y;
+static vga_colors fg_color;
+static vga_colors bg_color;
+static char* scroll_buf[0xfa0];
+
+
+static void set_char(int x,int y,char c) {
+  screen[xy_to_indx(x,y)]=c;
+  screen[xy_to_indx(x,y)+1]=(bg_color<<4)|fg_color;
+}
+
+void vga_clear() {
+  for (int y=0;y<height;y++) {
+    for (int x=0;x<width;x++) {
+      set_char(x,y,' ');
+    }
+  }
+}
+
+static void set_cursor(int x,int y) {
+  int pos=(x+(y*width));
+  port_byte_out(0x3D4,0xF);
+  port_byte_out(0x3D5,pos&0xFF);
+  port_byte_out(0x3D4,0xE);
+  port_byte_out(0x3D5,(pos&0xFF00)>>8);
+}
+
+void vga_init(text_fb_info framebuffer_info) {
+  x=0;
+  y=0;
+  fg_color=VGA_WHITE;
+  bg_color=VGA_BLACK;
+  screen=framebuffer_info.address;
+  width=framebuffer_info.width;
+  height=framebuffer_info.height;
+  port_byte_out(0x3D4,0xA);
+  port_byte_out(0x3D5,(port_byte_in(0x3D5)&0xC0)|14);
+  port_byte_out(0x3D4,0xB);
+  port_byte_out(0x3D5,(port_byte_in(0x3D5)&0xE0)|15);
+  set_cursor(0,0);
+  vga_clear();
+}
+
+void vga_write_string(const char* string) {
+  for (size_t i=0;i<strlen(string);i++) {
+    char c=string[i];
+    if (c=='\n') {
+      x=0;
+      y++;
+      #pragma GCC diagnostic push
+      #pragma GCC diagnostic ignored "-Wunused-value"
+      for (int i=0;i<67108864;i++) {
+        1+1;
+      }
+      #pragma GCC diagnostic pop
+    } else {
+      set_char(x,y,c);
+      x++;
+    }
+    if (x==width) {
+      x=0;
+      y++;
+    }
+    if (y==height) {
+      x=0;
+      y=24;
+      memcpy(scroll_buf,&screen[xy_to_indx(0,1)],xy_to_indx(0,24));
+      vga_clear();
+      memcpy(screen,scroll_buf,xy_to_indx(0,25));
+    }
+  }
+  set_cursor(x,y);
+}
+
+void vga_backspace() {
+  if (x!=0) {
+      x--;
+      set_char(x,y,' ');
+      set_cursor(x,y);
+  }
+}

vga_drv/vga.h

@@ -0,0 +1,29 @@
+#ifndef vga_H
+#define vga_H
+
+typedef enum {
+  VGA_BLACK=0,
+  VGA_BLUE=1,
+  VGA_GREEN=2,
+  VGA_CYAN=3,
+  VGA_RED=4,
+  VGA_PURPLE=5,
+  VGA_BROWN=6,
+  VGA_GRAY=7,
+  VGA_DARK_GRAY=8,
+  VGA_LIGHT_BLUE=9,
+  VGA_LIGHT_GREEN=10,
+  VGA_LIGHT_CYAN=11,
+  VGA_LIGHT_RED=12,
+  VGA_LIGHT_PURPLE=13,
+  VGA_YELLOW=14,
+  VGA_WHITE=15
+} vga_colors;
+
+
+void vga_init();
+void vga_write_string(const char *string);
+void vga_clear();
+void vga_backspace();
+
+#endif