arch: i386: put framebuffer ops in own file

Move all operations related to the x86 framebuffer into its own set of
files. This makes the TTY layer more architecture agnostic.

Signed-off-by: Danny Holman <dholman@gymli.org>

3 files changed, 122 insertions, 88 deletions

diff --git a/arch/i386/include/kernel/framebuffer.h b/arch/i386/include/kernel/framebuffer.h
new file mode 100644
index 0000000..ef0249c
--- /dev/null
+++ b/arch/i386/include/kernel/framebuffer.h
@@ -0,0 +1,17 @@
+#ifndef I386_FRAMEBUFFER_H
+#define I386_FRAMEBUFFER_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+void fb_init(void);
+void fb_setcolor(uint8_t color);
+void fb_putchar(char c);
+void fb_setpos(int x, int y);
+
+static inline void fb_write(const char *data, size_t size) {
+        for (size_t i = 0; i < size; i++)
+                fb_putchar(data[i]);
+}
+
+#endif
diff --git a/arch/i386/kernel/framebuffer.c b/arch/i386/kernel/framebuffer.c
new file mode 100644
index 0000000..602bddb
--- /dev/null
+++ b/arch/i386/kernel/framebuffer.c
@@ -0,0 +1,105 @@
+#include <kernel/vga.h>
+#include <kernel/paging.h>
+#include <kernel/pic.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 size_t fb_row;
+static size_t fb_column;
+static uint8_t fb_color;
+static uint16_t *framebuffer;
+
+void _enable_cursor(uint8_t cursor_start, uint8_t cursor_end) {
+        outb(0x3D4, 0x0A);
+        outb(0x3D5, (inb(0x3D5) & 0xC0) | cursor_start);
+
+        outb(0x3D4, 0x0B);
+        outb(0x3D5, (inb(0x3D5) & 0xE0) | cursor_end);
+}
+
+void _update_cursor(size_t x, size_t y) {
+        uint16_t pos = y * VGA_WIDTH + x;
+        
+        outb(0x3D4, 0x0F);
+        outb(0x3D5, (uint8_t)(pos & 0xFF));
+        outb(0x3D4, 0x0E);
+        outb(0x3D5, (uint8_t)((pos >> 8) & 0xFF));
+}
+
+void _fb_putentryat(unsigned char c, uint8_t color, size_t x, size_t y) {
+        const size_t index = y * VGA_WIDTH + x;
+        framebuffer[index] = vga_entry(c, color);
+}
+
+void _fb_scroll(void) {
+        for (size_t i = 0; i < VGA_HEIGHT-1; i++) {
+                for (size_t j = 0; j < VGA_WIDTH; j++)
+                        framebuffer[i * VGA_WIDTH + j] = VGA_MEMORY[(i+1) * VGA_WIDTH + j];
+        }
+}
+
+void fb_init(void) {
+        map_page(NULL, 0xB8000, (uintptr_t)VGA_MEMORY, 0x003);
+
+        fb_row = 0;
+        fb_column = 0;
+        fb_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
+        framebuffer = VGA_MEMORY;
+        for (size_t y = 0; y < VGA_HEIGHT; y++) {
+                for (size_t x = 0; x < VGA_WIDTH; x++)
+                        _fb_putentryat(' ', fb_color, x, y);
+        }
+        _enable_cursor(0, 0);
+        _update_cursor(0, 0);
+}
+
+void fb_setcolor(uint8_t color) {
+        fb_color = color;
+}
+
+void fb_setpos(int x, int y) {
+        fb_row = y;
+        fb_column = x;
+}
+
+void fb_putchar(char c) {
+        unsigned char uc = c;
+        switch (uc) {
+                case '\r':
+                        fb_column = 0;
+                        break;
+                case '\n':
+                        fb_column = 0;
+                        if (++fb_row == VGA_HEIGHT) {
+                                fb_row--;
+                                _fb_scroll();
+                        }
+                        break;
+                case '\t':
+                        fb_column += 4;
+                        if (++fb_column == VGA_WIDTH) {
+                                fb_column = 4;
+                                if (++fb_row == VGA_HEIGHT) {
+                                        fb_row--;
+                                        _fb_scroll();
+                                }
+                        }
+                        break;
+                default:
+                        _fb_putentryat(uc, fb_color, fb_column, fb_row);
+                        if (++fb_column == VGA_WIDTH) {
+                                fb_column = 0;
+                                if (++fb_row == VGA_HEIGHT) {
+                                        fb_row--;
+                                        _fb_scroll();
+                                }
+                        }
+                        break;
+        }
+        _update_cursor(fb_column, fb_row+1);
+}
diff --git a/arch/i386/kernel/tty.c b/arch/i386/kernel/tty.c
deleted file mode 100644
index d2bba53..0000000
--- a/arch/i386/kernel/tty.c
+++ /dev/null
@@ -1,88 +0,0 @@
-#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 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 = c;
-        switch (uc) {
-                case '\r':
-                        terminal_column = 0;
-                        break;
-                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));
-}