test: Add tests for all control instructions and base CPU implementation

1 files changed, 26 insertions, 0 deletions

diff --git a/Q1.core/Arch/InstructionEncoding.cs b/Q1.core/Arch/InstructionEncoding.cs
new file mode 100644
index 0000000..479d61f
--- /dev/null
+++ b/Q1.core/Arch/InstructionEncoding.cs
@@ -0,0 +1,26 @@
+namespace Q1.core.Arch;
+
+public static class InstructionEncoding
+{
+    public static void Decode(u16 instruction, out u8 opcode, out u8 m1, out u8 m2, out bool word)
+    {
+        word   = ((instruction     >> 15) & 0x1) != 0; // top bit
+        opcode = (u8)((instruction >> 8)  & 0x7F);     // 7 clean bits
+
+        m1 = (u8)((instruction >> 4) & 0x0F);
+        m2 = (u8)(instruction        & 0x0F);
+    }
+    
+    public static u16 Encode(u8 opcode, u8 m1, u8 m2, bool word)
+    {
+        u16 instruction = 0;
+
+        instruction |= (u16)((opcode & 0x7F) << 8);  // 7-bit opcode
+        instruction |= (u16)((word ? 1 : 0)  << 15); // top bit flag
+
+        instruction |= (u16)((m1 & 0x0F) << 4);
+        instruction |= (u16)(m2 & 0x0F);
+
+        return instruction;
+    }
+}
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