init: move ansiterm to `driver/`

2 files changed, 109 insertions, 0 deletions

diff --git a/src/init/driver/ansiterm.c b/src/init/driver/ansiterm.c
new file mode 100644
index 0000000..5b05af1
--- /dev/null
+++ b/src/init/driver/ansiterm.c
@@ -0,0 +1,106 @@
+#include <init/driver/driver.h>
+#include <shared/syscalls.h>
+#include <stdbool.h>
+
+struct vga_cell {
+	unsigned char c;
+	unsigned char style;
+} __attribute__((__packed__));
+static struct vga_cell vga[80 * 25];
+
+static handle_t tty_fd;
+static handle_t vga_fd;
+
+static struct {int x, y;} cursor = {0};
+static bool dirty = false;
+static bool pendingFlush = false;
+
+/* TODO unflushed writes mix with the kernel's vga driver */
+
+static void flush(void) {
+	_syscall_write(vga_fd, vga, sizeof vga, 0);
+	dirty = false;
+	pendingFlush = false;
+}
+
+static void scroll(void) {
+	for (size_t i = 0; i < 80 * 24; i++)
+		vga[i] = vga[i + 80];
+	for (size_t i = 80 * 24; i < 80 * 25; i++)
+		vga[i].c = ' ';
+	cursor.y--;
+	pendingFlush = true;
+}
+
+static void in_char(char c) {
+	switch (c) {
+		case '\n':
+			cursor.x = 0;
+			cursor.y++;
+			pendingFlush = true;
+			break;
+		case '\b':
+			if (--cursor.x < 0) cursor.x = 0;
+			break;
+		default:
+			vga[cursor.y * 80 + cursor.x++].c = c;
+	}
+
+	if (cursor.x >= 80) {
+		cursor.x = 0;
+		cursor.y++;
+	}
+	while (cursor.y >= 25) scroll();
+	dirty = true;
+}
+
+void ansiterm_drv(void) {
+	tty_fd = _syscall_open("/tty", 4);
+	_syscall_write(tty_fd, "ansiterm...\n", 12, 0);
+
+	vga_fd = _syscall_open("/vga", 4);
+	_syscall_read(vga_fd, vga, sizeof vga, 0);
+
+	// find first empty line
+	for (cursor.y = 0; cursor.y < 25; cursor.y++) {
+		for (cursor.x = 0; cursor.x < 80; cursor.x++) {
+			char c = vga[cursor.y * 80 + cursor.x].c;
+			if (c != ' ' && c != '\0') break;
+		}
+		if (cursor.x == 80) break;
+	}
+	cursor.x = 0;
+
+	static char buf[512];
+	struct fs_wait_response res;
+	while (!_syscall_fs_wait(buf, sizeof buf, &res)) {
+		switch (res.op) {
+			case VFSOP_OPEN:
+				// TODO check path
+				_syscall_fs_respond(NULL, 1);
+				break;
+
+			case VFSOP_WRITE:
+				_syscall_write(tty_fd, buf, res.len, 0);
+				for (int i = 0; i < res.len; i++)
+					in_char(buf[i]);
+				if (pendingFlush) flush();
+				_syscall_fs_respond(NULL, res.len);
+				break;
+
+			case VFSOP_READ:
+				if (res.capacity > sizeof buf)
+					res.capacity = sizeof buf;
+				if (dirty) flush();
+				size_t len = _syscall_read(tty_fd, buf, res.capacity, 0);
+				_syscall_fs_respond(buf, len);
+				break;
+
+			default:
+				_syscall_fs_respond(NULL, -1);
+				break;
+		}
+	}
+
+	_syscall_exit(1);
+}
diff --git a/src/init/driver/driver.h b/src/init/driver/driver.h
new file mode 100644
index 0000000..e854c65
--- /dev/null
+++ b/src/init/driver/driver.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void ansiterm_drv(void);