diff --git a/biosandbox/Emulation.h b/biosandbox/Emulation.h
index 4812fa5..df82271 100644
--- a/biosandbox/Emulation.h
+++ b/biosandbox/Emulation.h
@@ -7,7 +7,7 @@
 namespace bio {
 	namespace emu {
 
-		using instruction_set = std::vector<native_callable<int, int, unsigned char*, bool*>>;
+		using instruction_set = std::vector<native_callable<int, int, unsigned char*, bool*, std::vector<int>*>>;
 		
 		memory_dependent using mem_buffer = unsigned char[memsize];
 
@@ -31,6 +31,7 @@ namespace bio {
 			instruction_set isa;
 			mem_buffer<memsize> memory;
 			std::vector<symbol> symbols;
+			std::vector<int> callStack;
 			
 			virtual void load_app(application& app) = 0;
 			virtual void run_symbol(int symbol) = 0;
@@ -66,7 +67,7 @@ namespace bio {
 				bool returned = false;
 				until(returned || instructionPointer >= memsize) {
 					this->instructionPointer +=
-						this->isa[this->memory[instructionPointer]](instructionPointer, this->memory, &returned);
+						this->isa[this->memory[instructionPointer]](instructionPointer, this->memory, &returned, &this->callStack);
 
 					if (instructionPointer < 0 || instructionPointer > memsize) {
 						throw std::out_of_range("Symbol causes instruction pointer to err out of memory");
diff --git a/biosandbox/Intel.cpp b/biosandbox/Intel.cpp
index 685d1fe..6abf0dd 100644
--- a/biosandbox/Intel.cpp
+++ b/biosandbox/Intel.cpp
@@ -13,4 +13,10 @@ isa_instruction(bio::Intel::ISAs::iAPX86::invalid) {
 
 isa_instruction(bio::Intel::ISAs::iAPX86::nop) {
 	return 1;
+}
+
+isa_instruction(bio::Intel::ISAs::iAPX86::call_e8) {
+	short jump;
+	memcpy(&jump, memory + (position + 1), 2);
+	return jump + 3;
 }
\ No newline at end of file
diff --git a/biosandbox/Intel.h b/biosandbox/Intel.h
index 31dcb71..4e6994e 100644
--- a/biosandbox/Intel.h
+++ b/biosandbox/Intel.h
@@ -11,6 +11,7 @@ namespace bio {
 			namespace iAPX86 {
 				isa_instruction(invalid);
 				isa_instruction(nop);
+				isa_instruction(call_e8);
 			}
 		}
 
@@ -26,6 +27,8 @@ namespace bio {
 					this->isa.push_back(ISAs::iAPX86::invalid);
 				}
 
+
+				this->isa[0xE8] = ISAs::iAPX86::call_e8;
 				this->isa[0x90] = ISAs::iAPX86::nop;
 
 				times(sizeof(this->memory)) {
diff --git a/biosandbox/bsuml.h b/biosandbox/bsuml.h
index 94a2891..0eb21f2 100644
--- a/biosandbox/bsuml.h
+++ b/biosandbox/bsuml.h
@@ -18,7 +18,12 @@ using native_callable = T(*)(args...);
 
 // emulation-related definitions
 
-#define isa_instruction(x) int x(int position, unsigned char* memory, bool* emu_return)
+#define isa_instruction(x) int x(int position, unsigned char* memory, bool* emu_return, ptr<std::vector<int>> callstack)
+   // position = current instruction pointer position
+  // memory = memory buffer
+ // emureturn = end of symbol
+// callstack = callstack pointer 
+
 #define memory_dependent template<int memsize>
 #define memory_passdown(x) x<memsize>
 
diff --git a/gameenv/code/test b/gameenv/code/test
index 97781c5..0fa0477 100644
Binary files a/gameenv/code/test and b/gameenv/code/test differ
diff --git a/gameenv/code/test.asm b/gameenv/code/test.asm
index 80ecbaa..129c28d 100644
--- a/gameenv/code/test.asm
+++ b/gameenv/code/test.asm
@@ -1,7 +1,4 @@
 global main
 section .text
-func:
-mov eax, 1
-ret
 main:
-call func
\ No newline at end of file
+call 0
\ No newline at end of file
diff --git a/gameenv/code/test.exe b/gameenv/code/test.exe
deleted file mode 100644
index fa204e4..0000000
Binary files a/gameenv/code/test.exe and /dev/null differ