From 687badc14208b2240c2acbfd68b9e4295bd4efc2 Mon Sep 17 00:00:00 2001
From: Logan McNaughton <848146+loganmc10@users.noreply.github.com>
Date: Wed, 29 Jan 2025 10:49:29 +0100
Subject: [PATCH] Modify RSP sync points (#198)

* modify RSP sync points

* more

* more

* more

* more

* more

* more

* more
---
 src/device.rs                     |  1 +
 src/device/rdp.rs                 | 11 ++++++++++-
 src/device/rsp_interface.rs       | 28 +++++++++++++++++++++++-----
 src/device/rsp_su_instructions.rs |  3 ---
 4 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/src/device.rs b/src/device.rs
index 621faaa..b2970df 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -367,6 +367,7 @@ impl Device {
                 regs: [0; rsp_interface::SP_REGS_COUNT as usize],
                 regs2: [0; rsp_interface::SP_REGS2_COUNT as usize],
                 mem: [0; 0x2000],
+                last_status_value: 0,
                 fifo: [rsp_interface::RspDma {
                     dir: rsp_interface::DmaDir::None,
                     length: 0,
diff --git a/src/device/rdp.rs b/src/device/rdp.rs
index 971425c..c61f4db 100644
--- a/src/device/rdp.rs
+++ b/src/device/rdp.rs
@@ -52,7 +52,16 @@ pub fn read_regs_dpc(
     address: u64,
     _access_size: device::memory::AccessSize,
 ) -> u32 {
-    device.rdp.regs_dpc[((address & 0xFFFF) >> 2) as usize]
+    let reg = (address & 0xFFFF) >> 2;
+    match reg as u32 {
+        DPC_CURRENT_REG => {
+            if device.rdp.wait_frozen {
+                device.rsp.cpu.sync_point = true;
+            }
+            device.rdp.regs_dpc[reg as usize]
+        }
+        _ => device.rdp.regs_dpc[reg as usize],
+    }
 }
 
 pub fn write_regs_dpc(device: &mut device::Device, address: u64, value: u32, mask: u32) {
diff --git a/src/device/rsp_interface.rs b/src/device/rsp_interface.rs
index 2fbb404..cec05b5 100644
--- a/src/device/rsp_interface.rs
+++ b/src/device/rsp_interface.rs
@@ -81,6 +81,7 @@ pub struct Rsp {
     pub regs2: [u32; SP_REGS2_COUNT as usize],
     pub mem: [u8; 0x2000],
     pub fifo: [RspDma; 2],
+    pub last_status_value: u32,
 }
 
 pub fn read_mem_fast(
@@ -260,8 +261,27 @@ pub fn read_regs(
 ) -> u32 {
     let reg = (address & 0xFFFF) >> 2;
     match reg as u32 {
+        SP_DMA_BUSY_REG | SP_DMA_FULL_REG => {
+            if device.rsp.regs[reg as usize] != 0 {
+                device.rsp.cpu.sync_point = true;
+            }
+            device.rsp.regs[reg as usize]
+        }
+        SP_STATUS_REG => {
+            let value = device.rsp.regs[reg as usize]
+                & !(SP_STATUS_HALT | SP_STATUS_BROKE | SP_STATUS_INTR_BREAK);
+            if value == device.rsp.last_status_value && value != 0 {
+                device.rsp.cpu.sync_point = true;
+            }
+            device.rsp.last_status_value = value;
+            device.rsp.regs[reg as usize]
+        }
         SP_SEMAPHORE_REG => {
             let value = device.rsp.regs[reg as usize];
+            if value == 1 {
+                device.rsp.cpu.sync_point = true;
+                device.rsp.cpu.cycle_counter += 4; // needed for DK64
+            }
             device.rsp.regs[reg as usize] = 1;
             value
         }
@@ -284,9 +304,7 @@ pub fn write_regs(device: &mut device::Device, address: u64, value: u32, mask: u
         SP_SEMAPHORE_REG => {
             device::memory::masked_write_32(&mut device.rsp.regs[reg as usize], 0, mask)
         }
-        _ => {
-            device::memory::masked_write_32(&mut device.rsp.regs[reg as usize], value, mask);
-        }
+        _ => device::memory::masked_write_32(&mut device.rsp.regs[reg as usize], value, mask),
     }
 }
 
@@ -421,12 +439,13 @@ fn update_sp_status(device: &mut device::Device, w: u32) {
     if device.rsp.regs[SP_STATUS_REG as usize] & SP_STATUS_HALT == 0 && was_halted {
         device.rsp.cpu.broken = false;
         device.rsp.cpu.halted = false;
-        device.rsp.cpu.sync_point = false;
         do_task(device);
     }
 }
 
 fn do_task(device: &mut device::Device) {
+    device.rsp.cpu.sync_point = false;
+    device.rsp.last_status_value = 0;
     let timer = device::rsp_cpu::run(device);
 
     device::events::create_event(
@@ -450,7 +469,6 @@ fn rsp_event(device: &mut device::Device) {
         device.rsp.regs[SP_STATUS_REG as usize] |= SP_STATUS_HALT;
         return;
     }
-    device.rsp.cpu.sync_point = false;
     do_task(device)
 }
 
diff --git a/src/device/rsp_su_instructions.rs b/src/device/rsp_su_instructions.rs
index b454e73..07d0e9f 100644
--- a/src/device/rsp_su_instructions.rs
+++ b/src/device/rsp_su_instructions.rs
@@ -565,8 +565,6 @@ pub fn mfc0(device: &mut device::Device, opcode: u32) {
             device::memory::AccessSize::Word,
         )
     }
-    device.rsp.cpu.cycle_counter += 4; // needed for DK64
-    device.rsp.cpu.sync_point = true;
 }
 
 pub fn mtc0(device: &mut device::Device, opcode: u32) {
@@ -592,7 +590,6 @@ pub fn mtc0(device: &mut device::Device, opcode: u32) {
             !device::rsp_interface::SP_STATUS_HALT; // set halt when event happens
         device.rsp.cpu.halted = true // the RSP can halt itself by setting SP_SET_HALT
     }
-    device.rsp.cpu.sync_point = true;
 }
 
 pub fn mfc2(device: &mut device::Device, opcode: u32) {