1 files changed, 131 insertions, 0 deletions
diff --git a/kernel/src/tty/term.c b/kernel/src/tty/term.c
new file mode 100644
index 0000000..4f75788
--- /dev/null
+++ b/kernel/src/tty/term.c
@@ -0,0 +1,131 @@
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys.h>
+#include <print.h>
+
+#include "term.h"
+#include "color.h"
+#include "cursor.h"
+
+uint16_t *buffer;
+uint8_t x, y;
+uint8_t color;
+
+const uint16_t blank = (uint16_t) 0 | VGA_BLACK << 12 | VGA_WHITE << 8;
+
+static void term_clear_line(int y) {
+    if (y < 0 || y >= TERM_H)
+        return;
+    for (uint8_t x = 0; x < TERM_W; x++) {
+	    const size_t index = y * TERM_W + x;
+	    buffer[index] = blank;
+    }
+}
+
+void term_init (void) {
+    x = 0;
+    y = 0;
+    buffer = (uint16_t*) 0xb8000;
+    term_setfg(VGA_WHITE);
+    term_setbg(VGA_BLACK);
+    term_clear();
+}
+
+void term_setpos(uint8_t xp, uint8_t yp) {
+    x = xp;
+    y = yp;
+    cursor_setpos(x, y);
+}
+
+void term_scroll (int lines) {
+    int_disable(); 
+    y -= lines;
+    if (!lines) return;
+    if(lines >= TERM_H || lines <= -TERM_H) {
+		term_clear();
+	} else if(lines > 0) {
+		memmove(buffer, buffer + lines * TERM_W, 2 * (TERM_H - lines) * TERM_W);
+        term_clear_line(TERM_H - lines);
+	} else {
+		memmove(buffer + lines * TERM_W, buffer + lines, (TERM_H + lines) * TERM_W);
+	}
+    int_enable();
+}
+
+void term_setfg(enum VGAColor c) {
+    color = (color & 0xF0) | c;
+}
+
+void term_setbg(enum VGAColor c) {
+    color = (color & 0x0F) | c << 4;
+}
+
+void term_clear (void) {
+    for (uint8_t y = 0; y < TERM_H; y++)
+        term_clear_line(y);
+}
+
+uint32_t term_save(void) {
+    uint32_t state = 0;
+    state |= (uint32_t) x << 16;
+    state |= (uint32_t) y << 8;
+    state |= (uint32_t) color << 0;
+    return state;
+}
+
+void term_load(uint32_t state) {
+    x = (uint8_t) (state >> 16);
+    y = (uint8_t) (state >> 8);
+    color = (uint8_t) (state >> 0);
+    cursor_setpos(x, y);
+}
+
+uint16_t term_save_col(void) {
+    return color;
+}
+
+void term_load_col(uint16_t c) {
+    color = c;
+}
+
+void putchar(int c) {
+    switch (c) {
+        case '\n':
+            x = 0;
+            y++;
+            break;
+        case '\t':
+            x += 4;
+            break;
+        case '\v':
+        case '\f':
+            y++;
+            break;
+        case '\r':
+            x = 0;
+            break;
+        default: {
+	        const size_t index = y * TERM_W + x;
+	        buffer[index] = c | (uint16_t) color << 8;
+            x++;
+        }
+    }
+
+	if (x >= TERM_W) {
+		x = 0;
+        y++;
+	}
+
+	if (y >= TERM_H) {
+		term_scroll(y - (TERM_H - 1));
+        y = TERM_H - 1;
+    }
+
+    cursor_setpos(x, y);
+}
+
+bool term_newline(void) {
+    return x == 0;
+}