feat: add pmm, add vmm, add allocator, create memory management foundation

kernel/src/debug/serial.rs

@@ -0,0 +1,53 @@
+use core::arch::asm;
+
+pub struct SerialPort(u16);
+
+impl SerialPort {
+    pub const COM1: u16 = 0x3F8;
+
+    pub unsafe fn init() -> Self {
+        let port = Self::COM1;
+        // В новых версиях Rust даже внутри unsafe fn 
+        // вызовы других unsafe функций требуют явного блока
+        unsafe {
+            outb(port + 1, 0x00); // Disable interrupts
+            outb(port + 3, 0x80); // Enable DLAB
+            outb(port + 0, 0x03); // Divisor 3 (38400 baud)
+            outb(port + 1, 0x00);
+            outb(port + 3, 0x03); // 8 bits, no parity, 1 stop bit
+            outb(port + 2, 0xC7); // Enable FIFO
+            outb(port + 4, 0x0B); // IRQs enabled, RTS/DSR set
+        }
+        SerialPort(port)
+    }
+
+    fn is_transmit_empty(&self) -> bool {
+        unsafe { (inb(self.0 + 5) & 0x20) != 0 }
+    }
+
+    pub fn send(&self, data: u8) {
+        while !self.is_transmit_empty() {}
+        unsafe { outb(self.0, data); }
+    }
+}
+
+impl core::fmt::Write for SerialPort {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        for byte in s.bytes() { self.send(byte); }
+        Ok(())
+    }
+}
+
+unsafe fn outb(port: u16, val: u8) {
+    unsafe {
+        asm!("out dx, al", in("dx") port, in("al") val, options(nomem, nostack, preserves_flags));
+    }
+}
+
+unsafe fn inb(port: u16) -> u8 {
+    let res: u8;
+    unsafe {
+        asm!("in al, dx", out("al") res, in("dx") port, options(nomem, nostack, preserves_flags));
+    }
+    res
+}