From 0a6e0b6833d9d2472c4e384c125dd31bf83c6cc0 Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Thu, 2 Feb 2023 16:52:33 +1100
Subject: [PATCH] almost timing

---
 Cargo.lock           | 11 +++++++++++
 Cargo.toml           |  3 ++-
 src/processor/mod.rs | 11 +++++++++--
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index dfc3079..9772426 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -77,6 +77,7 @@ name = "gb-emu"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "spin_sleep",
 ]
 
 [[package]]
@@ -196,6 +197,16 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "spin_sleep"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cafa7900db085f4354dbc7025e25d7a839a14360ea13b5fc4fd717f2d3b23134"
+dependencies = [
+ "once_cell",
+ "winapi",
+]
+
 [[package]]
 name = "strsim"
 version = "0.10.0"
diff --git a/Cargo.toml b/Cargo.toml
index 893b61c..bfa26a0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,4 +6,5 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-clap = {version = "4.1.1", features = ["derive"]}
\ No newline at end of file
+clap = {version = "4.1.1", features = ["derive"]}
+spin_sleep = "1.1.1"
\ No newline at end of file
diff --git a/src/processor/mod.rs b/src/processor/mod.rs
index c0e04ac..cf1188f 100644
--- a/src/processor/mod.rs
+++ b/src/processor/mod.rs
@@ -1,4 +1,4 @@
-use std::mem::transmute;
+use std::{mem::transmute, time::Duration};
 
 use crate::{verbose_println, Memory};
 
@@ -25,6 +25,10 @@ pub struct CPU {
     pub last_instruction_addr: u16,
 }
 
+// MHz
+const CLOCK_SPEED: f64 = 4.194304 * 1000000.;
+const SPEEDUP: f64 = 1.;
+
 impl CPU {
     pub fn exec_next(&mut self) {
         self.last_instruction_addr = self.reg.pc;
@@ -43,7 +47,10 @@ impl CPU {
             opcode,
             self.last_instruction_addr
         );
-        self.run_opcode(opcode);
+        let cycles = self.run_opcode(opcode);
+        spin_sleep::sleep(Duration::from_secs_f64(
+            (cycles * 4) as f64 / (CLOCK_SPEED * SPEEDUP),
+        ));
     }
 
     fn next_opcode(&mut self) -> u8 {