From 0e3b70f7d348f5c8c8a13f1f431b9f135dae3257 Mon Sep 17 00:00:00 2001
From: Jaby <jaby@william.zone>
Date: Tue, 28 Apr 2026 22:12:50 +0100
Subject: [PATCH] Add simple integration tests

---
 .../src/Overlay/GTETest/gte_test.cpp          | 15 +++++
 include/PSX/GTE/gte.hpp                       | 66 +++++++++++++++++++
 2 files changed, 81 insertions(+)

diff --git a/examples/PoolBox/application/src/Overlay/GTETest/gte_test.cpp b/examples/PoolBox/application/src/Overlay/GTETest/gte_test.cpp
index a6207e44..46e5846e 100644
--- a/examples/PoolBox/application/src/Overlay/GTETest/gte_test.cpp
+++ b/examples/PoolBox/application/src/Overlay/GTETest/gte_test.cpp
@@ -109,6 +109,20 @@ namespace GTETest {
         GTE::set_geom_screen(256);
     }
 
+    static void check_values() {
+        static constexpr int32_t Value = 256;
+
+        GTE::set_geom_screen(Value);
+        printf("set_geom_screen: %i == %i\n", GTE::get_geom_screen(), Value);
+
+        int32_t x = 256;
+        int32_t y = 512;
+
+        GTE::set_geom_offset(x, y);
+        GTE::get_geom_offset(x, y);
+        printf("%i == 256 && %i == 512\n", x, y);
+    }
+
     static bool update_or_exit() {
         Periphery::query_controller();
         if(Shared::back_menu.update(Make::PositionI16(0, GPU::Display::Height - 32))) {
@@ -154,6 +168,7 @@ namespace GTETest {
 
     void main() {
         setup();
+        check_values();
 
         while(true) {
             if(update_or_exit()) {
diff --git a/include/PSX/GTE/gte.hpp b/include/PSX/GTE/gte.hpp
index 043644a4..23765cfe 100644
--- a/include/PSX/GTE/gte.hpp
+++ b/include/PSX/GTE/gte.hpp
@@ -1,6 +1,47 @@
 #pragma once
 #include "gte_instruction.hpp"
 
+// GTE Overview
+// GTE Data Register Summary (cop2r0-31)
+//
+// `mtc2` (Move To Coprocessor 2): Sets a Data Register (0–31).
+// `mfc2` (Move From Coprocessor 2): Gets a Data Register (0–31).
+//
+//  | cop2r0-1   | 3xS16 | VXY0,VZ0            | Vector 0 (X,Y,Z)                      |
+//  | cop2r2-3   | 3xS16 | VXY1,VZ1            | Vector 1 (X,Y,Z)                      |
+//  | cop2r4-5   | 3xS16 | VXY2,VZ2            | Vector 2 (X,Y,Z)                      |
+//  | cop2r6     | 4xU8  | RGBC                | Color/code value                      |
+//  | cop2r7     | 1xU16 | OTZ                 | Average Z value (for Ordering Table)  |
+//  | cop2r8     | 1xS16 | IR0                 | 16bit Accumulator (Interpolate)       |
+//  | cop2r9-11  | 3xS16 | IR1,IR2,IR3         | 16bit Accumulator (Vector)            |
+//  | cop2r12-15 | 6xS16 | SXY0,SXY1,SXY2,SXYP | Screen XY-coordinate FIFO  (3 stages) |
+//  | cop2r16-19 | 4xU16 | SZ0,SZ1,SZ2,SZ3     | Screen Z-coordinate FIFO   (4 stages) |
+//  | cop2r20-22 | 12xU8 | RGB0,RGB1,RGB2      | Color CRGB-code/color FIFO (3 stages) |
+//  | cop2r23    | 4xU8  | (RES1)              | Prohibited                            |
+//  | cop2r24    | 1xS32 | MAC0                | 32bit Maths Accumulators (Value)      |
+//  | cop2r25-27 | 3xS32 | MAC1,MAC2,MAC3      | 32bit Maths Accumulators (Vector)     |
+//  | cop2r28-29 | 1xU15 | IRGB,ORGB           | Convert RGB Color (48bit vs 15bit)    |
+//  | cop2r30-31 | 2xS32 | LZCS,LZCR           | Count Leading-Zeroes/Ones (sign bits) |
+//
+// GTE Control Register Summary (cop2r32-63)
+// ctc2 (Copy To Control Coprocessor 2): Sets a Control Register (cnt0–31).
+// cfc2 (Copy From Control Coprocessor 2): Gets a Control Register (cnt0–31).
+//
+//  | cop2r32-36 9xS16 RT11RT12,..,RT33 | Rotation matrix     (3x3)         | cnt0-4   |
+//  | cop2r37-39 3x 32 TRX,TRY,TRZ      | Translation vector  (X,Y,Z)       | cnt5-7   |
+//  | cop2r40-44 9xS16 L11L12,..,L33    | Light source matrix (3x3)         | cnt8-12  |
+//  | cop2r45-47 3x 32 RBK,GBK,BBK      | Background color    (R,G,B)       | cnt13-15 |
+//  | cop2r48-52 9xS16 LR1LR2,..,LB3    | Light color matrix source (3x3)   | cnt16-20 |
+//  | cop2r53-55 3x 32 RFC,GFC,BFC      | Far color           (R,G,B)       | cnt21-23 |
+//  | cop2r56-57 2x 32 OFX,OFY          | Screen offset       (X,Y)         | cnt24-25 | (1bit sign, 15bit integer, 16bit fraction)
+//  | cop2r58 BuggyU16 H                | Projection plane distance.        | cnt26    | (0bit sign, 16bit integer, 0bit fraction)
+//  | cop2r59      S16 DQA              | Depth queing parameter A (coeff)  | cnt27    |
+//  | cop2r60       32 DQB              | Depth queing parameter B (offset) | cnt28    |
+//  | cop2r61-62 2xS16 ZSF3,ZSF4        | Average Z scale factors           | cnt29-30 |
+//  | cop2r63      U20 FLAG             | Returns any calculation errors    | cnt31    |
+
+
+
 namespace JabyEngine {
     namespace GTE {
         static constexpr auto StackSize = 16;
@@ -213,6 +254,19 @@ namespace JabyEngine {
             __asm__ volatile("ctc2 $13, $25"    :: "r"(off_x), "r"(off_y) : "$12", "$13");
         }
 
+        static void get_geom_offset(int32_t &off_x, int32_t &off_y) {
+            int32_t raw_x, raw_y;
+
+            __asm__ volatile (
+                "cfc2 %0, $24\n"
+                "cfc2 %1, $25"
+                : "=r" (raw_x), "=r" (raw_y)
+            );
+
+            off_x = raw_x >> 16;
+            off_y = raw_y >> 16;
+        }
+
         /*
             SetGeomScreen(h)
             
@@ -222,6 +276,18 @@ namespace JabyEngine {
             __asm__ volatile("ctc2 %0, $26" :: "r"(h));
         }
 
+        /*
+            GetGeomScreen() (???)
+            
+            Get distance from viewpoint to screen.
+        */
+        static int32_t get_geom_screen() {
+            int32_t h;
+
+            __asm__ volatile("cfc2 %0, $26" : "=r"(h));
+            return h;
+        }
+
         // Implementations for the MATRIX struct
         inline MATRIX& MATRIX :: comp(const MATRIX& matrix) {
             return comp_matrix(matrix, *this, *this);