From 20dd72e40dc2728d3c5335d860e4b8ab8da14fcc Mon Sep 17 00:00:00 2001
From: Aleksa Vučković <aleksav013@gmail.com>
Date: Mon, 25 Oct 2021 00:36:33 +0200
Subject: Changing build system to recursive make

---
 src/c/vga.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 src/c/vga.c

(limited to 'src/c/vga.c')

diff --git a/src/c/vga.c b/src/c/vga.c
new file mode 100644
index 0000000..07dec60
--- /dev/null
+++ b/src/c/vga.c
@@ -0,0 +1,126 @@
+#include"../include/types.h"
+#include"../include/string.h"
+#include"../include/asm.h"
+
+static const size_t VGA_WIDTH = 80;
+static const size_t VGA_HEIGHT = 25;
+
+
+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 terminal_row;
+size_t terminal_column;
+uint8_t terminal_color;
+uint16_t* terminal_buffer;
+ 
+void terminal_initialize()
+{
+    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_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 movescreen()
+{
+    terminal_row--;
+    for(size_t i=0;i<VGA_HEIGHT;i++) for(size_t j=0;j<VGA_WIDTH;j++) terminal_buffer[i*VGA_WIDTH+j]=terminal_buffer[(i+1)*VGA_WIDTH+j];
+}
+
+void next_field()
+{
+    if(++terminal_column==VGA_WIDTH) terminal_column=0,terminal_row++;
+}
+
+void previous_field()
+{
+    if(terminal_column) terminal_column--;
+    else terminal_row--,terminal_column=VGA_WIDTH-1;
+}
+ 
+void terminal_putchar(char c)
+{
+    if(c=='\n') terminal_column=0,terminal_row++;
+    else
+    {
+	terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
+	next_field();
+    }
+    if (terminal_row==VGA_HEIGHT) movescreen();
+}
+ 
+void terminal_writestring(char* data)
+{
+    for(int i=0;data[i]!='\0';i++) terminal_putchar(data[i]);
+}
+
+void terminal_writeint(uint32_t num)
+{
+    char string[100];
+    for(int i=0;i<100;i++) string[i]='\0';
+    char *str=string;
+    itos(num,str);
+    terminal_writestring(str);
+}
+
+void terminal_writefloat(double num)
+{
+    char string[100];
+    for(int i=0;i<100;i++) string[i]='\0';
+    char *str=string;
+    ftos(num,str);
+    terminal_writestring(str);
+}
+
+void prompt()
+{
+    terminal_writestring("[user@myos] > ");
+}
+
+void clear()
+{
+    for(size_t i=0;i<VGA_HEIGHT;i++) for(size_t j=0;j<VGA_WIDTH;j++) terminal_putchar(' ');
+    terminal_column=0;
+    terminal_row=0;
+}
-- 
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