Arithmetic Circuit Additions and Fixes

Subtraction, multiplication, and division should work properly.
Added sign, round, and exponent circuits.

code/modules/integrated_electronics/arithmetic.dm

@@ -11,6 +11,9 @@
 /obj/item/integrated_circuit/arithmetic/addition
 	name = "addition circuit"
 	desc = "This circuit can add numbers together."
+	extended_desc = "The order that the calculation goes is;<br>\
+	result = ((((A + B) + C) + D) ... ) and so on, until all pins have been added.  \
+	Null pins are ignored."
 	icon_state = "addition"
 
 /obj/item/integrated_circuit/arithmetic/addition/do_work()
@@ -29,30 +32,47 @@
 /obj/item/integrated_circuit/arithmetic/subtraction
 	name = "subtraction circuit"
 	desc = "This circuit can subtract numbers."
+	extended_desc = "The order that the calculation goes is;<br>\
+	result = ((((A - B) - C) - D) ... ) and so on, until all pins have been subtracted.  \
+	Null pins are ignored.  Pin A <b>must</b> be a number or the circuit will not function."
 	icon_state = "subtraction"
 
 /obj/item/integrated_circuit/arithmetic/subtraction/do_work()
-	if(..())
-		var/result = 0
-		for(var/datum/integrated_io/input/I in inputs)
-			I.pull_data()
-			if(isnum(I.data))
-				result = result - I.data
+	var/datum/integrated_io/A = inputs[1]
+	if(!isnum(A.data))
+		return
+	var/result = A.data
 
-		for(var/datum/integrated_io/output/O in outputs)
-			O.data = result
-			O.push_data()
+	for(var/datum/integrated_io/input/I in inputs)
+		if(I == A)
+			continue
+		I.pull_data()
+		if(isnum(I.data))
+			result = result - I.data
+
+	for(var/datum/integrated_io/output/O in outputs)
+		O.data = result
+		O.push_data()
 
 // *Multiply* //
 
 /obj/item/integrated_circuit/arithmetic/multiplication
 	name = "multiplication circuit"
 	desc = "This circuit can multiply numbers."
+	extended_desc = "The order that the calculation goes is;<br>\
+	result = ((((A * B) * C) * D) ... ) and so on, until all pins have been multiplied.  \
+	Null pins are ignored.  Pin A <b>must</b> be a number or the circuit will not function."
 	icon_state = "multiplication"
 
-/obj/item/integrated_circuit/arithmetic/subtraction/do_work()
-	var/result = 0
+
+/obj/item/integrated_circuit/arithmetic/multiplication/do_work()
+	var/datum/integrated_io/A = inputs[1]
+	if(!isnum(A.data))
+		return
+	var/result = A.data
 	for(var/datum/integrated_io/input/I in inputs)
+		if(I == A)
+			continue
 		I.pull_data()
 		if(isnum(I.data))
 			result = result * I.data
@@ -66,11 +86,20 @@
 /obj/item/integrated_circuit/arithmetic/division
 	name = "division circuit"
 	desc = "This circuit can divide numbers, just don't think about trying to divide by zero!"
+	extended_desc = "The order that the calculation goes is;<br>\
+	result = ((((A / B) / C) / D) ... ) and so on, until all pins have been divided.  \
+	Null pins, and pins containing 0, are ignored.  Pin A <b>must</b> be a number or the circuit will not function."
 	icon_state = "division"
 
 /obj/item/integrated_circuit/arithmetic/division/do_work()
-	var/result = 0
+	var/datum/integrated_io/A = inputs[1]
+	if(!isnum(A.data))
+		return
+	var/result = A.data
+
 	for(var/datum/integrated_io/input/I in inputs)
+		if(I == A)
+			continue
 		I.pull_data()
 		if(isnum(I.data) && I.data != 0) //No runtimes here.
 			result = result / I.data
@@ -79,6 +108,73 @@
 		O.data = result
 		O.push_data()
 
+//^ Exponent ^//
+
+/obj/item/integrated_circuit/arithmetic/exponent
+	name = "exponent circuit"
+	desc = "Outputs A to the power of B."
+	icon_state = "exponent"
+	inputs = list("A", "B")
+
+/obj/item/integrated_circuit/arithmetic/exponent/do_work()
+	var/result = 0
+	var/datum/integrated_io/A = inputs[1]
+	var/datum/integrated_io/B = inputs[2]
+	if(isnum(A.data) && isnum(B.data))
+		result = A.data ** B.data
+
+	for(var/datum/integrated_io/output/O in outputs)
+		O.data = result
+		O.push_data()
+
+// +-Sign-+ //
+
+/obj/item/integrated_circuit/arithmetic/sign
+	name = "sign circuit"
+	desc = "This will say if a number is positive, negative, or zero."
+	extended_desc = "Will output 1, -1, or 0, depending on if A is a postive number, a negative number, or zero, respectively."
+	icon_state = "sign"
+	inputs = list("A")
+
+/obj/item/integrated_circuit/arithmetic/sign/do_work()
+	var/result = 0
+	var/datum/integrated_io/A = inputs[1]
+	if(isnum(A.data))
+		if(A.data > 0)
+			result = 1
+		else if (A.data < 0)
+			result = -1
+		else
+			result = 0
+
+	for(var/datum/integrated_io/output/O in outputs)
+		O.data = result
+		O.push_data()
+
+// Round //
+
+/obj/item/integrated_circuit/arithmetic/round
+	name = "round circuit"
+	desc = "Rounds A to the nearest B multiple of A."
+	extended_desc = "If B is not given a number, it will output the floor of A instead."
+	icon_state = "round"
+	inputs = list("A", "B")
+
+/obj/item/integrated_circuit/arithmetic/round/do_work()
+	var/result = 0
+	var/datum/integrated_io/A = inputs[1]
+	var/datum/integrated_io/B = inputs[2]
+	if(isnum(A.data))
+		if(isnum(B.data) && B.data != 0)
+			result = round(A.data, B.data)
+		else
+			result = round(A.data)
+
+	for(var/datum/integrated_io/output/O in outputs)
+		O.data = result
+		O.push_data()
+
+
 // Absolute //
 
 /obj/item/integrated_circuit/arithmetic/absolute
@@ -103,6 +199,7 @@
 /obj/item/integrated_circuit/arithmetic/average
 	name = "average circuit"
 	desc = "This circuit is of average quality, however it will compute the average for numbers you give it."
+	extended_desc = "Note that null pins are ignored, where as a pin containing 0 is included in the averaging calculation."
 	icon_state = "average"
 
 /obj/item/integrated_circuit/arithmetic/average/do_work()
@@ -137,6 +234,8 @@
 /obj/item/integrated_circuit/arithmetic/random
 	name = "random number generator circuit"
 	desc = "This gives a random (integer) number between values A and B inclusive."
+	extended_desc = "'Inclusive' means that the upper bound is included in the range of numbers, e.g. L = 1 and H = 3 will allow \
+	for outputs of 1, 2, or 3.  L being the higher number is not <i>strictly</i> required."
 	icon_state = "random"
 	inputs = list("L","H")