From 8cd22309667cf3da9c357e5b7dca43e8b6a2f9c0 Mon Sep 17 00:00:00 2001
From: Danny Holman <dholman@gymli.org>
Date: Fri, 21 Jan 2022 12:10:05 -0600
Subject: arch: i386: move non-critial files out of boot

Move all files not needed for the bootstrap process out of boot and into
the main x86 source directory.

Signed-off-by: Danny Holman <dholman@gymli.org>
---
 arch/i386/kernel/tty.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 arch/i386/kernel/tty.c

(limited to 'arch/i386/kernel/tty.c')

diff --git a/arch/i386/kernel/tty.c b/arch/i386/kernel/tty.c
new file mode 100644
index 0000000..f929408
--- /dev/null
+++ b/arch/i386/kernel/tty.c
@@ -0,0 +1,88 @@
+#include <kernel/vga.h>
+#include <kernel/tty.h>
+#include <kernel/string.h>
+#include <stddef.h>
+#include <stdint.h>
+
+static const size_t VGA_WIDTH = 80;
+static const size_t VGA_HEIGHT = 25;
+//static uint16_t *const VGA_MEMORY = (uint16_t*)0xC03FF000;
+static uint16_t *const VGA_MEMORY = (uint16_t*)0xB8000;
+
+static size_t terminal_row;
+static size_t terminal_column;
+static uint8_t terminal_color;
+static uint16_t *terminal_buffer;
+
+void tty_init(void) {
+        terminal_row = 0;
+        terminal_column = 0;
+        terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
+        terminal_buffer = VGA_MEMORY;
+        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 tty_setcolor(uint8_t color) {
+        terminal_color = color;
+}
+
+void tty_putentryat(unsigned 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_scroll(void) {
+        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 tty_putchar(char c) {
+        unsigned char uc;
+
+        uc = c;
+        switch (uc) {
+                case '\n':
+                        terminal_column = 0;
+                        if (++terminal_row == VGA_HEIGHT) {
+                                terminal_row--;
+                                terminal_scroll();
+                        }
+                        break;
+                case '\t':
+                        terminal_column += 4;
+                        if (++terminal_column == VGA_WIDTH) {
+                                terminal_column = 4;
+                                if (++terminal_row == VGA_HEIGHT) {
+                                        terminal_row--;
+                                        terminal_scroll();
+                                }
+                        }
+                        break;
+                default:
+                        tty_putentryat(uc, terminal_color, terminal_column, terminal_row);
+                        if (++terminal_column == VGA_WIDTH) {
+                                terminal_column = 0;
+                                if (++terminal_row == VGA_HEIGHT) {
+                                        terminal_row--;
+                                        terminal_scroll();
+                                }
+                        }
+                        break;
+        }
+}
+
+void tty_write(const char *data, size_t size) {
+        for (size_t i = 0; i < size; i++)
+                tty_putchar(data[i]);
+}
+
+void tty_writestring(const char *data) {
+        tty_write(data, strlen(data));
+}
-- 
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