Fill in all exception and IRQ entries. Handle PIT, keyboard IRQs

arch/x86_64/src/interrupt/syscall.rs

@@ -0,0 +1,22 @@
+#[naked]
+pub unsafe extern fn syscall() {
+    extern {
+        fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize) -> usize;
+    }
+
+    let a;
+    let b;
+    let c;
+    let d;
+    let e;
+    let f;
+    asm!("" : "={rax}"(a), "={rbx}"(b), "={rcx}"(c), "={rdx}"(d), "={rsi}"(e), "={rdi}"(f)
+        : : : "intel", "volatile");
+
+    let a = syscall(a, b, c, d, e, f);
+
+    asm!("" : : "{rax}"(a) : : "intel", "volatile");
+
+    // Pop scratch registers, error code, and return
+    asm!("iretq" : : : : "intel", "volatile");
+}