From 16a5b4c9ed410daba848a781f8b8978846c6b836 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 2 Oct 2021 19:48:17 +0000
Subject: implement serial/tty input

---
 src/kernel/arch/i386/tty/serial.c | 5 +++++
 src/kernel/arch/i386/tty/serial.h | 1 +
 src/kernel/arch/i386/tty/tty.c    | 5 +++++
 3 files changed, 11 insertions(+)

(limited to 'src/kernel/arch/i386')

diff --git a/src/kernel/arch/i386/tty/serial.c b/src/kernel/arch/i386/tty/serial.c
index 6ddc05b..2b89ecf 100644
--- a/src/kernel/arch/i386/tty/serial.c
+++ b/src/kernel/arch/i386/tty/serial.c
@@ -35,6 +35,11 @@ static void serial_putchar(char c) {
 	port_outb(COM1, c);
 }
 
+char serial_read(void) {
+	while ((port_inb(COM1 + 5) & 0x01) == 0); // wait for DR
+	return port_inb(COM1);
+}
+
 void serial_write(const char *buf, size_t len) {
 	for (size_t i = 0; i < len; i++)
 		serial_putchar(buf[i]);
diff --git a/src/kernel/arch/i386/tty/serial.h b/src/kernel/arch/i386/tty/serial.h
index 2332113..751e528 100644
--- a/src/kernel/arch/i386/tty/serial.h
+++ b/src/kernel/arch/i386/tty/serial.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <stddef.h>
 
+char serial_read(void);
 void serial_write(const char *buf, size_t len);
 void serial_init(void);
diff --git a/src/kernel/arch/i386/tty/tty.c b/src/kernel/arch/i386/tty/tty.c
index bae65c5..5a65221 100644
--- a/src/kernel/arch/i386/tty/tty.c
+++ b/src/kernel/arch/i386/tty/tty.c
@@ -11,6 +11,11 @@ void tty_init(void) {
 	serial_write("<3 ", 3);
 }
 
+void tty_read(char *buf, size_t len) {
+	for (size_t i = 0; i < len; i++)
+		buf[i] = serial_read();
+}
+
 void tty_write(const char *buf, size_t len) {
 	vga_write(buf, len);
 	serial_write(buf, len);
-- 
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