From 536f7619b85014f59c80de5fad663e71135841a2 Mon Sep 17 00:00:00 2001
From: Jaby <fenir50@web.de>
Date: Wed, 24 Jan 2024 18:19:45 -0500
Subject: [PATCH] Support enabeling GTE

---
 .../BootLoader/boot_loader.hpp                |  4 ++
 src/Library/internal-include/mipscalls.hpp    | 38 +++++++++++++++++++
 src/Library/src/BootLoader/gte_boot.cpp       | 20 ++++++++++
 src/Library/src/BootLoader/start_boot.cpp     |  1 +
 4 files changed, 63 insertions(+)
 create mode 100644 src/Library/internal-include/mipscalls.hpp
 create mode 100644 src/Library/src/BootLoader/gte_boot.cpp

diff --git a/src/Library/internal-include/BootLoader/boot_loader.hpp b/src/Library/internal-include/BootLoader/boot_loader.hpp
index 08170100..47816578 100644
--- a/src/Library/internal-include/BootLoader/boot_loader.hpp
+++ b/src/Library/internal-include/BootLoader/boot_loader.hpp
@@ -13,6 +13,10 @@ namespace JabyEngine {
             void setup();
         }
 
+        namespace GTE {
+            void setup();
+        }
+
         namespace SPU {
             void stop_voices();
             void setup();
diff --git a/src/Library/internal-include/mipscalls.hpp b/src/Library/internal-include/mipscalls.hpp
new file mode 100644
index 00000000..2a74af18
--- /dev/null
+++ b/src/Library/internal-include/mipscalls.hpp
@@ -0,0 +1,38 @@
+#pragma once
+#include <PSX/Auxiliary/bits.hpp>
+
+namespace JabyEngine {
+    namespace MIPS {
+        struct SR {
+            static constexpr auto IEc = Bit(0);                   // Current Interrupt Enable  (0=Disable, 1=Enable)
+            static constexpr auto KUc = Bit(1);                   // Current Kernel/User Mode  (0=Kernel, 1=User)
+            static constexpr auto IEp = Bit(2);                   // Previous Interrupt Disable
+            static constexpr auto KUp = Bit(3);                   // Previous Kernal/User Mode
+            static constexpr auto IEo = Bit(4);                   // Old Interrupt Disable
+            static constexpr auto KUo = Bit(5);                   // Old Kernal/User Mode
+            static constexpr auto Im  = BitRange::from_to(8, 15); // 8 bit interrupt mask fields. When set the corresponding interrupts are allowed to cause an exception.
+            static constexpr auto Isc = Bit(16);                  // Isolate Cache (0=No, 1=Isolate) When isolated, all load and store operations are targetted to the Data cache, and never the main memory. (Used by PSX Kernel, in combination with Port FFFE0130h)
+            static constexpr auto Swc = Bit(17);                  // Swc Swapped cache mode (0=Normal, 1=Swapped) Instruction cache will act as Data cache and vice versa. Use only with Isc to access & invalidate Instr. cache entries. (Not used by PSX Kernel)
+            static constexpr auto PZ  = Bit(18);                  // PZ  When set cache parity bits are written as 0.
+            static constexpr auto CM  = Bit(19);                  // CM  Shows the result of the last load operation with the D-cache isolated. It gets set if the cache really contained data for the addressed memory location.
+            static constexpr auto PE  = Bit(20);                  // Cache parity error (Does not cause exception)
+            static constexpr auto TS  = Bit(21);                  // TLB shutdown. Gets set if a programm address simultaneously matches 2 TLB entries. (initial value on reset allows to detect extended CPU version?)
+            static constexpr auto BEV = Bit(22);                  // Boot exception vectors in RAM/ROM (0=RAM/KSEG0, 1=ROM/KSEG1)
+            static constexpr auto RE  = Bit(25);                  // Reverse endianness   (0=Normal endianness, 1=Reverse endianness) Reverses the byte order in which data is stored in memory. (lo-hi -> hi-lo) (Has affect only to User mode, not to Kernal mode) (?) (The bit doesn't exist in PSX ?)
+            static constexpr auto CU0 = Bit(28);                  // COP0 Enable (0=Enable only in Kernal Mode, 1=Kernal and User Mode)
+            static constexpr auto CU1 = Bit(29);                  // COP1 Enable (0=Disable, 1=Enable) (none such in PSX)
+            static constexpr auto CU2 = Bit(30);                  // COP2 Enable (0=Disable, 1=Enable) (GTE in PSX)
+            static constexpr auto CU3 = Bit(31);                  // COP3 Enable (0=Disable, 1=Enable) (none such in PSX)
+
+            static uint32_t read() {
+                uint32_t sr;
+                __asm__("mfc0 %0, $12" : "=rm"(sr));
+                return sr;
+            }
+
+            static void write(uint32_t sr) {
+                __asm__("mtc0 %0, $12" :: "rm"(sr));
+            }
+        };
+    }
+}
\ No newline at end of file
diff --git a/src/Library/src/BootLoader/gte_boot.cpp b/src/Library/src/BootLoader/gte_boot.cpp
new file mode 100644
index 00000000..caa93717
--- /dev/null
+++ b/src/Library/src/BootLoader/gte_boot.cpp
@@ -0,0 +1,20 @@
+#include "../../internal-include/mipscalls.hpp"
+#include <PSX/GTE/gte.hpp>
+#include <PSX/System/syscalls.hpp>
+
+
+namespace JabyEngine {
+    namespace boot {
+        namespace GTE {
+            void setup() {
+                SysCall::EnterCriticalSection();
+                    const auto sr = bit::set(MIPS::SR::read(), MIPS::SR::CU2);
+                    MIPS::SR::write(sr);
+                SysCall::ExitCriticalSection();
+
+                JabyEngine::GTE::set_geom_offset(0, 0);
+                JabyEngine::GTE::set_geom_screen(512);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Library/src/BootLoader/start_boot.cpp b/src/Library/src/BootLoader/start_boot.cpp
index 8bab75db..1c584a56 100644
--- a/src/Library/src/BootLoader/start_boot.cpp
+++ b/src/Library/src/BootLoader/start_boot.cpp
@@ -43,6 +43,7 @@ namespace JabyEngine {
                 __debug_boot_color_at(::JabyEngine::GPU::Color24::Yellow(), DebugX, DebugY, DebugScale);
                 GPU::setup();
                 GPU::display_logo();
+                GTE::setup();
                 
                 //Pause??
                 SPU::setup();