bubble sort + fixed issue when writing to reference in ram.py

src/Makefile

@@ -1,5 +1,13 @@
 LDFLAGS="-L/usr/local/opt/flex/lib"
 
+
+bubble_sort: ram
+	./ram < bubble_sort.asm
+	echo "### machine.py ###"
+	cat machine.py
+	echo "### execution ###"
+	python machine.py
+
 a_pow_b: ram
 	./ram < a_pow_b.asm
 	echo "### machine.py ###"

src/bubble_sort.asm

@@ -0,0 +1,30 @@
+(20, 17, 18, 26, 8, 19, 9, 11, 12, 28, 13, 7, 21, 15, 29, 14, 1, 16, 3, 22, 4)
+ADD(1, 0, r0)       // PART 1: copy table to work registries. r0 counter
+ADD(1, i0, r1)      // upper limit
+JE(r0, r1, 5)       // loop control
+ADD(r0, 3, r2)      // r2 copied element destination address, (r0 to r3, reserved registries)
+ADD(i@r0, 0, r@r2)  // copy element
+ADD(1, r0, r0)      // increment counter
+JUMP(-4)            // loop
+ADD(i0, 4, r2)      // PART 2: bubble sort, counter upper limit
+ADD(4, 0, r0)       // r0 counter, 1st element to compare
+ADD(5, 0, r1)       // r1 counter, 2nd element to compare
+JE(r1, r2, 8)       // inner loop control
+JL(r@r1, r@r0, 4)   // if 2nd element > 1st element, jump (elements already ordered)
+ADD(r@r0, 0, r3)    // temp value
+ADD(r@r1, 0, r@r0)  // replace 2nd element with the 1st
+ADD(r3, 0, r@r1)    // replace 1st element with the 2nd (stored in temp value)
+ADD(1, r0, r0)      // increment counter 1st element
+ADD(1, r1, r1)      // increment counter 2nd element
+JUMP(-7)            // inner loop
+JE(5, r2, 3)        // outer loop control
+SUB(r2, 1, r2)      // decrement upper limit
+JUMP(-12)           // outer loop
+ADD(4, 0, r0)       // PART 3: copy table from work registries to output, r0 counter
+ADD(4, i0, r1)      // upper limit
+JE(r0, r1, 5)       // loop control
+SUB(r0, 3, r2)      // r2 copied element destination address, starts from o1
+ADD(r@r0, 0, o@r2)  // copy element
+ADD(1, r0, r0)      // increment counter
+JUMP(-4)            // loop
+ADD(i0, 0, o0)      // output size in o0

src/ram.py

@@ -45,7 +45,7 @@ class Ram(object):
             raise TypeError("cannot write on value")
         elif type_register == "@": # reference
             target_index = self.read_register(ref_origin, index)
-            self.write_register(ref_target, target_index, value)
+            self.write_register(value, ref_target, target_index)
 
     def op(self, type_op, r1, r2, r3):
         self.current += 1