From cb96c84100c2ca0b86adaceec7674d8d48b93a98 Mon Sep 17 00:00:00 2001
From: Logan McNaughton <848146+loganmc10@users.noreply.github.com>
Date: Sat, 7 Oct 2023 19:23:44 -0600
Subject: [PATCH] small opt

---
 src/device.rs                  |  1 +
 src/device/cpu.rs              |  2 ++
 src/device/cpu_instructions.rs | 26 +++++---------------------
 src/device/memory.rs           |  1 -
 src/device/tlb.rs              |  4 +---
 5 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/src/device.rs b/src/device.rs
index 6b3fcb18..8b624243 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -127,6 +127,7 @@ impl Device {
                 gpr: [0; 32],
                 clock_rate: 0,
                 pc: 0xBFC00000,
+                pc_phys: 0,
                 llbit: false,
                 lo: 0,
                 hi: 0,
diff --git a/src/device/cpu.rs b/src/device/cpu.rs
index e56db382..f037b96b 100644
--- a/src/device/cpu.rs
+++ b/src/device/cpu.rs
@@ -22,6 +22,7 @@ pub struct Cpu {
     pub branch_state: BranchState,
     pub gpr: [u64; 32],
     pub pc: u64,
+    pub pc_phys: u64,
     pub lo: u64,
     pub hi: u64,
     pub running: u8,
@@ -241,6 +242,7 @@ pub fn run(device: &mut device::Device) {
         if err {
             continue; // TLB exception
         }
+        device.cpu.pc_phys = phys_address;
         if cached {
             device::cache::icache_fetch(device, phys_address)
         } else {
diff --git a/src/device/cpu_instructions.rs b/src/device/cpu_instructions.rs
index 301c7035..24b39211 100644
--- a/src/device/cpu_instructions.rs
+++ b/src/device/cpu_instructions.rs
@@ -49,18 +49,10 @@ pub fn bits_above_mask<T: Into<u64>>(x: T) -> u64 {
 }
 
 pub fn check_relative_idle_loop(device: &mut device::Device, opcode: u32) {
-    let (phys_address, _, err) = device::memory::translate_address(
-        device,
-        device.cpu.pc,
-        device::memory::AccessType::Lookup,
-    );
-    if err {
-        return;
-    }
     if imm(opcode) as i16 == -1
-        && device.memory.fast_read[(phys_address >> 16) as usize](
+        && device.memory.fast_read[(device.cpu.pc_phys >> 16) as usize](
             device,
-            phys_address + 4,
+            device.cpu.pc_phys + 4,
             device::memory::AccessSize::Word,
         ) == 0
     {
@@ -69,18 +61,10 @@ pub fn check_relative_idle_loop(device: &mut device::Device, opcode: u32) {
 }
 
 pub fn check_absolute_idle_loop(device: &mut device::Device, opcode: u32) {
-    let (phys_address, _, err) = device::memory::translate_address(
-        device,
-        device.cpu.pc,
-        device::memory::AccessType::Lookup,
-    );
-    if err {
-        return;
-    }
-    if (opcode & 0x3FFFFFF) as u64 == (phys_address & 0x0FFFFFFF) >> 2
-        && device.memory.fast_read[(phys_address >> 16) as usize](
+    if (opcode & 0x3FFFFFF) as u64 == (device.cpu.pc_phys & 0x0FFFFFFF) >> 2
+        && device.memory.fast_read[(device.cpu.pc_phys >> 16) as usize](
             device,
-            phys_address + 4,
+            device.cpu.pc_phys + 4,
             device::memory::AccessSize::Word,
         ) == 0
     {
diff --git a/src/device/memory.rs b/src/device/memory.rs
index 39c0f0a4..829f1f83 100644
--- a/src/device/memory.rs
+++ b/src/device/memory.rs
@@ -24,7 +24,6 @@ pub const MM_IS_VIEWER: usize = 0x13ff0000;
 pub enum AccessType {
     Write,
     Read,
-    Lookup,
 }
 
 #[derive(Copy, Clone)]
diff --git a/src/device/tlb.rs b/src/device/tlb.rs
index 35d8e7a8..8caee882 100644
--- a/src/device/tlb.rs
+++ b/src/device/tlb.rs
@@ -261,9 +261,7 @@ pub fn get_physical_address(
         }
     }
 
-    if access_type != device::memory::AccessType::Lookup {
-        device::exceptions::tlb_miss_exception(device, address, access_type)
-    }
+    device::exceptions::tlb_miss_exception(device, address, access_type);
 
     return (0, false, true);
 }