(BIG CHANGE) Switch instruction identification/execution to use a plain match tree, should improve performance by quite a bit

src/core.rs

@@ -7,7 +7,7 @@
 use crate::{
     consts::{Addr, RegId, RegValue},
     decode::Instruction,
-    instructions::find_runner,
+    instructions::find_and_exec,
     mem::MemConfig,
 };
 
@@ -57,11 +57,9 @@ impl Core {
 
             let instr = Instruction(instr);
 
-            let runner = find_runner(instr);
-
-            if let Some(runner) = runner {
-                let res = runner(self, instr);
+            let res = find_and_exec(instr, self);
 
+            if let Some(res) = res {
                 match res {
                     InstructionResult::Normal => {}
                     InstructionResult::Exception(_e) => {