- compiler works for basic maths expressions and functions

- basic pointers and reading values from pointers works
- writing to pointers not yet implemented (looks painful so a problem
  for tomorrow)
- updated print library. the compiler has this hardcoded in all programs
  for now

resources/dsa/lib/maths/core.dsa

@@ -59,3 +59,46 @@ _divmod_end:
 	mov bpr, spr
 	pop bpr
 	return
+
+// multiply.dsa - improved version
+// Multiplies two 32-bit numbers using shift-and-add
+//
+// Usage:
+// push operand2  (multiplier)
+// push operand1  (multiplicand)
+// call multiply::multiply
+// pop result
+// pop zero       (discard second argument)
+
+new_multiply:
+    push bpr
+    mov spr, bpr
+
+    ldw bpr, rg0, 8     // rg0 = multiplicand
+    ldw bpr, rg1, 12    // rg1 = multiplier
+
+    lli 0, rg2          // rg2 = result (accumulator)
+    lli 32, rg3         // rg3 = bit counter
+
+mult_loop:
+    // Check if lowest bit of multiplier is 1
+    lli 1, acc
+    and rg1, acc, acc   // acc = rg1 & 1
+    cmp acc, zero
+    jeq skip_add        // if (rg1 & 1) == 0, skip addition
+
+    // Add multiplicand to result
+    add rg2, rg0, rg2
+
+skip_add:
+    shl rg0, 1          // shift multiplicand left
+    shr rg1, 1          // shift multiplier right
+
+    dec rg3
+    cmp rg3, zero
+    jgt mult_loop
+
+    stw rg2, bpr, 8     // store result
+    mov bpr, spr
+    pop bpr
+    return