diff --git a/instructions.c b/instructions.c
index e86eea3..b8d94c1 100644
--- a/instructions.c
+++ b/instructions.c
@@ -1,4 +1,4 @@
-// PID: 730677144 
+// PID: 730677144
 // I pledge the COMP 211 honor code.
 
 #include <stdint.h>
@@ -16,7 +16,7 @@
 // Return:      instruction_type: R_TYPE or I_TYPE (see structures)
 //
 instruction_type get_type_of_instruction(uint32_t instruct) {
-    if (bit_select(instruct, 26, 32) == 0) {
+    if (bit_select(instruct, OPCODE_START_BIT, OPCODE_END_BIT) == 0) {
         return R_TYPE;
     } else {
         return I_TYPE;
@@ -35,8 +35,15 @@ instruction_type get_type_of_instruction(uint32_t instruct) {
 //              you will have to set: rs, rt, rd, shamt, func
 //
 r_instruction* create_r_instruction(uint32_t instruct) {
-    // TODO
-    return NULL;
+    r_instruction* r = malloc(sizeof(r_instruction));
+
+    r->rs = bit_select(instruct, RS_START_BIT, RS_END_BIT);
+    r->rt = bit_select(instruct, RT_START_BIT, RT_END_BIT);
+    r->rd = bit_select(instruct, RD_START_BIT, RD_END_BIT);
+    r->shamt = bit_select(instruct, SHAMT_START_BIT, SHAMT_END_BIT);
+    r->func = bit_select(instruct, FUNC_START_BIT, FUNC_END_BIT);
+
+    return r;
 }  // end create_r_instruction() function
 
 // ------------------------------------
@@ -50,6 +57,12 @@ r_instruction* create_r_instruction(uint32_t instruct) {
 //              you will have to set: opcode, rs, rt, immediate
 //
 i_instruction* create_i_instruction(uint32_t instruct) {
-    // TODO
-    return NULL;
+    i_instruction* i = malloc(sizeof(i_instruction));
+
+    i->opcode = bit_select(instruct, OPCODE_START_BIT, OPCODE_END_BIT);
+    i->rs = bit_select(instruct, RS_START_BIT, RS_END_BIT);
+    i->rt = bit_select(instruct, RT_START_BIT, RT_END_BIT);
+    i->immediate = bit_select(instruct, IMMEDIATE_START_BIT, IMMEDIATE_END_BIT);
+
+    return i;
 }  // end create_i_instruction() function
diff --git a/lab04 b/lab04
index 8f81b49..4f12e03 100755
Binary files a/lab04 and b/lab04 differ
diff --git a/lab04.c b/lab04.c
index a6f0bea..b46690d 100644
--- a/lab04.c
+++ b/lab04.c
@@ -1,4 +1,4 @@
-// PID: 730677144 
+// PID: 730677144
 // I pledge the COMP 211 honor code.
 
 #include <limits.h>
@@ -32,12 +32,10 @@ int main() {
             return EXIT_SUCCESS;
 
         if (get_type_of_instruction(instruct) == R_TYPE) {
-            printf("R_TYPE instruction\n");
             r_instruction* r_instruct = create_r_instruction(instruct);
             execute_r_instruction(r_instruct);
             free(r_instruct);
         } else {  // I_TYPE
-            printf("I_TYPE instruction\n");
             i_instruction* i_instruct = create_i_instruction(instruct);
             execute_i_instruction(i_instruct);
             free(i_instruct);
@@ -72,7 +70,36 @@ int main() {
 // Return:      None
 //
 void execute_r_instruction(r_instruction* instruct) {
-    // TODO
+    switch (instruct->func) {
+        case SLL_FUNC:
+            registers[instruct->rd] = registers[instruct->rt]
+                                      << instruct->shamt;
+            break;
+        case SRA_FUNC:
+            registers[instruct->rd] =
+                registers[instruct->rt] >> instruct->shamt;
+            break;
+        case ADD_FUNC:
+            registers[instruct->rd] =
+                registers[instruct->rs] + registers[instruct->rt];
+            break;
+        case SUB_FUNC:
+            registers[instruct->rd] =
+                registers[instruct->rs] - registers[instruct->rt];
+            break;
+        case AND_FUNC:
+            registers[instruct->rd] =
+                registers[instruct->rs] & registers[instruct->rt];
+            break;
+        case OR_FUNC:
+            registers[instruct->rd] =
+                registers[instruct->rs] | registers[instruct->rt];
+            break;
+        default:
+            fprintf(stderr, "Invalid function code!\n");
+            exit(EXIT_FAILURE);
+    }
+
 }  // end execute_r_instruction() function
 
 // ------------------------------------
@@ -89,5 +116,21 @@ void execute_r_instruction(r_instruction* instruct) {
 // Return:      None
 //
 void execute_i_instruction(i_instruction* instruct) {
-    // TODO
+    switch (instruct->opcode) {
+        case ADDI_OPCODE:
+            registers[instruct->rt] =
+                registers[instruct->rs] + instruct->immediate;
+            break;
+        case ANDI_OPCODE:
+            registers[instruct->rt] =
+                registers[instruct->rs] & instruct->immediate;
+            break;
+        case ORI_OPCODE:
+            registers[instruct->rt] =
+                registers[instruct->rs] | instruct->immediate;
+            break;
+        default:
+            fprintf(stderr, "Invalid opcode!\n");
+            exit(EXIT_FAILURE);
+    }
 }  // end execute_i_instruction() function