add integer multiply

imath.asm

@@ -0,0 +1,16 @@
+pub mul_low:
+	mov r3, 0 ; result
+	mov r4, 31 ; loop counter
+	
+	mull_loop:
+		asr r5, r2, 31
+		and r5, r5, r1
+		lsl r5, r5, r4
+		add r3, r3, r5
+		lsl r2, r2, 1
+		sub r4, r4, 1
+		cmp r4, 0
+		jge mull_loop
+	mov r1, r3
+	
+	jmp r13

stdlib.asm

@@ -27,4 +27,5 @@
 
 ; ===== TYPES =====
 
-pub include bit
+pub include bit
+pub include imath