From 7551a3680a32b1643251cfeb8ba696da6e052709 Mon Sep 17 00:00:00 2001
From: Madeline Cronin <maddie.henlo@gmail.com>
Date: Sun, 8 Sep 2024 23:13:22 +0100
Subject: [PATCH] Write tests for control flow instructions and related
 behaviours.

---
 src/processor.rs | 57 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/src/processor.rs b/src/processor.rs
index 796634d..e852cbf 100644
--- a/src/processor.rs
+++ b/src/processor.rs
@@ -220,7 +220,8 @@ impl <'a> Processor<'a> {
                 }
                 let address = {
                     if toggles.2 { //Pop from the stack
-                        self.reg[30] += 1;
+                        self.reg[30] = self.reg[30].wrapping_add(1); //Operations influenced by
+                                                                     //code should be unchecked.
                         self.memory[self.reg[30] as usize]
                     }
                     else { //Use a register value
@@ -231,7 +232,7 @@ impl <'a> Processor<'a> {
 
                 if toggles.1 { //Push to stack
                     self.memory[self.reg[30] as usize] = self.reg[31] + 2;
-                    self.reg[30] -= 1;
+                    self.reg[30] = self.reg[30].wrapping_sub(1);
                 }
                 if toggles.0 { //Relative jump
                     self.reg[31] = self.reg[31].wrapping_add(address);
@@ -362,7 +363,7 @@ mod tests {
         assert_eq!(processor.reg[2], 7);
     }
     #[test]
-    fn overflow () {
+    fn add_overflow () {
         let mut memory = [0x0600, u16::MAX, 0x0608, 5, 0x0140, 0x0044, 0xA618, 5, 0, 0];
         let mut disk = [0];
         let mut vram = [0];
@@ -374,7 +375,7 @@ mod tests {
         assert_eq!(processor.reg[3], 5);
     }
     #[test]
-    fn signed_overflow () {
+    fn add_signed_overflow () {
         let mut memory = [0x0600, i16::MAX as u16, 0x0608, 5, 0x01E0, 0x0044, 0x5618, 5, 0, 0];
         let mut disk = [0];
         let mut vram = [0];
@@ -590,4 +591,52 @@ mod tests {
         }
         assert_eq!(processor.reg[2], 5);
     }
+    #[test]
+    fn cf_static_jump() {
+        let mut memory = [0x0600, 6, 0x0400, 0x0000, 0x0600, 13, 0, 0];
+        let mut disk = [0];
+        let mut vram = [0];
+        let mut processor = new(&mut memory, &mut disk, &mut vram);
+        loop {
+            if processor.run() {break};
+        }
+        assert_eq!(processor.reg[0], 6);
+    }
+    #[test]
+    fn cf_dyn_jump() {
+        let mut memory = [0x0600, 4, 0x0480, 0x0000, 0x0600, 13, 0, 0];
+        let mut disk = [0];
+        let mut vram = [0];
+        let mut processor = new(&mut memory, &mut disk, &mut vram);
+        loop {
+            if processor.run() {break};
+        }
+        assert_eq!(processor.reg[0], 4);
+    }
+    #[test]
+    fn cf_push_pop() {
+        let mut memory = [0xA420, 0x0000, 0x0300, 0x0000, 0x06F0, 10, 0x0440, 0x0000, 0, 0, 0];
+        let mut disk = [0];
+        let mut vram = [0];
+        let mut processor = new(&mut memory, &mut disk, &mut vram);
+        let mut counter = 0;
+        loop {
+            if processor.run() {break};
+            counter += 1;
+            if counter > 20 {panic!()};
+        }
+    }
+    #[test]
+    fn cf_interrupt() {
+        let mut memory = [0xA420, 0x0000, 0x0300, 0x0000, 0x06F0, 14, 0x0600, 2, 0x049C, 0x0000, 0x0450, 0x0000, 0, 0, 0];
+        let mut disk = [0];
+        let mut vram = [0];
+        let mut processor = new(&mut memory, &mut disk, &mut vram);
+        let mut counter = 0;
+        loop {
+            if processor.run() {break};
+            counter += 1;
+            if counter > 30 {panic!()};
+        }
+    }
 }
-- 
2.43.4