Changed execute function to use function pointer array w/ S

src/emulator/execute.c

@@ -16,44 +16,33 @@
 // instruction if the shift flag is enabled.
 #define DPI_WIDEMOV_SHIFT 16
 
+// Type definition for a pointer to a function that executes a particular type 
+// of a64instruction (requires pointer to the processor state to update, and a
+// pointer to the instruction struct to execute).
+typedef void (*executeFunction)(Machine *, a64inst_instruction *);
+
 // Prototypes
 static void executeSDT(Machine *state, a64inst_instruction *inst);
 static void executeBranch(Machine *state, a64inst_instruction *inst);
 static void executeDPImmediate(Machine *state, a64inst_instruction *inst);
 static void executeDPRegister(Machine *state, a64inst_instruction *inst);
 
+// Halt function definition
+static void executeHalt(Machine *state, a64inst_instruction *inst) { /*NOP*/ }
+
+// Define a constant array mapping instruction type enum values to their
+// corresponding execute functions
+const executeFunction EXECUTE_FUNCTIONS[] =
+    {&executeDPImmediate,
+     &executeDPRegister,
+     &executeSDT,
+     &executeSDT,
+     &executeBranch,
+     &executeHalt};
+
+// Main execute function
 void execute(Machine *state, a64inst_instruction *inst) {
-
-    switch (inst->type) {
-
-        // Halt the program
-        case a64inst_HALT:
-            break;
-
-        // Execute a data processing immediate instruction
-        case a64inst_DPIMMEDIATE:
-            executeDPImmediate(state, inst);
-            break;
-
-        // Execute a branch instruction
-        case a64inst_BRANCH:
-            executeBranch(state, inst);
-            break;
-
-        // Execute a data processing register instruction
-        case a64inst_DPREGISTER:
-            executeDPRegister(state, inst); 
-            break;
-
-        case a64inst_SINGLETRANSFER: 
-            executeSDT(state, inst);
-            break;
-
-        // Unknown instruction
-        default:
-            break;
-    }
-
+    EXECUTE_FUNCTIONS[inst->type](state, inst);
 }
 
 // Updates N and Z condition codes given the machine and a result value