Merge branch 'master' of git.homolo.gy:forestbelton/island-story

Makefile

@@ -20,7 +20,7 @@ OFILES := $(SFILES:%.s=%.o) $(MAP_S:%.s=%.o)
 is.gb is.gb.sym: $(OFILES)
 	@echo "[LINK]     is.gb"
 	@rgblink -o $@ -n $@.sym $(OFILES)
-	@rgbfix -v $@
+	@rgbfix -v -p 0 $@
 
 $(OFILES): $(MAP_INC)
 $(OFILES): $(SPRITE_2BPP)

src/map.s

@@ -141,20 +141,12 @@ Map_Scroll::
     ld c, a
 
     ; HL = _SCRN0 + 32 * (SCY/8 - 2)
-.find_vram_ptr:
     ld a, [rSCY]
     sub 16
     srl a
     srl a
     srl a
-    ld d, a
-    ld e, 32
-    ld hl, _SCRN0
-.0:
-    ld a, d
-    ADD16 hl
-    dec e
-    jr nz, .0
+    call get_row_ptr
 
     call enqueue_row_write
 
@@ -177,8 +169,7 @@ Map_Scroll::
     srl a
     srl a
     dec a
-    ld e, a
-    call compute_vram_ptr
+    call get_row_ptr
 
     LOAD_MAPX
 
@@ -335,22 +326,18 @@ Map_Update::
     ret
 
 ; Computes the offset into map RAM
-; @param e The map RAM y-coordinate
+; @param a The map RAM y-coordinate
 ; @return hl Pointer into map RAM
-compute_vram_ptr:
-    push bc
+get_row_ptr:
+    push de
+    ld d, 0
+    ld e, a
+    REPT 5
+        SLA16 de
+    ENDR
     ld hl, _SCRN0
-    ld b, 0
-    ld c, SCRN_VX_B
-    ld a, e
-.loop:
-    or a
-    jr z, .done
-    add hl, bc
-    dec a
-    jr .loop
-.done:
-    pop bc
+    add hl, de
+    pop de
     ret
 
 ; Write a row of map data into row buffer