Add dubiously helpful macros

inc/util.inc

@@ -1,4 +1,5 @@
 ; Stores a 16-bit value into the address stored in HL
+; 5 bytes, 24 clocks
 ; \1 The value to store (immediate or register)
 MACRO STORE16
     ld [hl], HIGH(\1)
@@ -6,11 +7,44 @@ MACRO STORE16
     ld [hl], LOW(\1)
 ENDM
 
-; Stores an 8-bit value into memory
-; \1 Write address
-; \2 8-bit value
-MACRO SET8
-    ld h, HIGH(\1)
-    ld l, LOW(\1)
-    ld [hl], \2
+; Reads a 16-bit value into HL
+; \1 The address to read
+MACRO LOAD16
+    ld a, [\1]
+    ld l, a
+    ld a, [\1 + 1]
+    ld h, a
+ENDM
+
+; Copies bytes to a memory location
+; 7 bytes, 48*N-4 clocks
+; \1 Destination address (16-bit register)
+; \2 Source address (16-bit register)
+; \3 Number of bytes (8-bit register)
+MACRO MEMCPY
+.loop\@:
+    ld a, [\2] ; 8
+    inc \2 ; 8
+    ld [\1], a ; 8
+    inc \1 ; 8
+    dec \3 ; 4
+    jr nz, .loop\@ ; 12/8
+ENDM
+
+; Adds A to a 16-bit register
+; \1 Destination register
+MACRO ADD16
+    add LOW(\1)
+    ld LOW(\1), a
+    adc HIGH(\1)
+    sub LOW(\1)
+    ld HIGH(\1), a
+ENDM
+
+; Load between two 16-bit registers
+; \1 Destination register
+; \2 Source register
+MACRO LD16
+    ld HIGH(\1), HIGH(\2)
+    ld LOW(\1), LOW(\2)
 ENDM