consistency and optimization improvement (#87)

* Update GalacticArmada.asm - optimizations and consistency

* Update gameplay-background.asm

* Update gameplay-background.asm

* Update gameplay-state.asm

* Update hud.asm

* Update hud.asm

* Update interrupts.asm

* Update player.asm

* Update enemies.asm

* Update bullets.asm

* Update enemy-player-collision.asm

* Update enemy-bullet-collision.asm

* Update entry-point.md

* Update story-state.asm

* Update story-state.asm

* Update title-screen-state.asm

* Update vblank-utils.asm

* Update background-utils.asm

* Update collision-utils.asm

* Update input-utils.asm

* Update math.asm

* Update memory-utils.asm

* Update metasprites.asm

* Update sprites-utils.asm

* Update text-utils.asm

galactic-armada/src/main/GalacticArmada.asm

@@ -19,10 +19,9 @@ EntryPoint:
 	
 ; ANCHOR: entry-point-end
 	; Shut down audio circuitry
-	ld a, 0
+	xor a
 	ld [rNR52], a
-
-	ld a, 0
+	; We don't actually need another xor a here, because the value of A doesn't change between these two instructions
 	ld [wGameState], a
 
 	; Wait for the vertical blank phase before initiating the library
@@ -34,7 +33,7 @@ EntryPoint:
 	call InitSprObjLibWrapper
 
 	; Turn the LCD off
-	ld a, 0
+	xor a
 	ld [rLCDC], a
 
 	; Load our common text font into VRAM
@@ -47,7 +46,6 @@ EntryPoint:
 	; During the first (blank) frame, initialize display registers
 	ld a, %11100100
 	ld [rBGP], a
-    ld a, %11100100
 	ld [rOBP0], a
 
 ; ANCHOR_END: entry-point-end
@@ -58,18 +56,17 @@ NextGameState::
 	; Do not turn the LCD off outside of VBlank
     call WaitForOneVBlank
 
-	call ClearBackground;
+	call ClearBackground
 
 
 	; Turn the LCD off
-	ld a, 0
+	xor a
 	ld [rLCDC], a
 
-	ld a, 0
-	ld [rSCX],a
-	ld [rSCY],a
-	ld [rWX],a
-	ld [rWY],a
+	ld [rSCX], a
+	ld [rSCY], a
+	ld [rWX], a
+	ld [rWY], a
 	; disable interrupts
 	call DisableInterrupts
 	
@@ -78,21 +75,21 @@ NextGameState::
 
 	; Initiate the next state
 	ld a, [wGameState]
-	cp a, 2 ; 2 = Gameplay
+	cp 2 ; 2 = Gameplay
 	call z, InitGameplayState
 	ld a, [wGameState]
-	cp a, 1 ; 1 = Story
+	cp 1 ; 1 = Story
 	call z, InitStoryState
 	ld a, [wGameState]
-	cp a, 0 ; 0 = Menu
+	and a ; 0 = Menu
 	call z, InitTitleScreenState
 
 	; Update the next state
 	ld a, [wGameState]
-	cp a, 2 ; 2 = Gameplay
+	cp 2 ; 2 = Gameplay
 	jp z, UpdateGameplayState
-	cp a, 1 ; 1 = Story
+	cp 1 ; 1 = Story
 	jp z, UpdateStoryState
 	jp UpdateTitleScreenState
 
-; ANCHOR_END: next-game-state
+; ANCHOR_END: next-game-state

galactic-armada/src/main/states/gameplay/gameplay-background.asm

@@ -28,11 +28,9 @@ InitializeBackground::
 	ld bc, starFieldMapEnd - starFieldMap
     call CopyDEintoMemoryAtHL_With52Offset
 
-	ld a, 0
-	ld [mBackgroundScroll+0],a
-	ld a, 0
-	ld [mBackgroundScroll+1],a
-
+	xor a
+	ld [mBackgroundScroll], a
+	ld [mBackgroundScroll+1], a
 	ret
 ; ANCHOR_END: gameplay-background-initialize
 
@@ -42,13 +40,13 @@ UpdateBackground::
 
 	; Increase our scaled integer by 5
 	; Get our true (non-scaled) value, and save it for later usage in bc
-	ld a , [mBackgroundScroll+0]
-	add a , 5
-    ld b,a
-	ld [mBackgroundScroll+0], a
-	ld a , [mBackgroundScroll+1]
-	adc a , 0
-    ld c,a
+	ld a, [mBackgroundScroll]
+	add a, 5
+    ld b, a
+	ld [mBackgroundScroll], a
+	ld a, [mBackgroundScroll+1]
+	adc 0
+    ld c, a
 	ld [mBackgroundScroll+1], a
 ; ANCHOR_END: gameplay-background-update-start
 
@@ -65,8 +63,7 @@ UpdateBackground::
     rr b
 
     ; Use the de-scaled low byte as the backgrounds position
-    ld a,b
+    ld a, b
 	ld [rSCY], a
-
 	ret
-; ANCHOR_END: gameplay-background-update-end
+; ANCHOR_END: gameplay-background-update-end

galactic-armada/src/main/states/gameplay/gameplay-state.asm

@@ -17,10 +17,10 @@ wLivesText::  db "lives", 255
 InitGameplayState::
 
 	ld a, 3
-	ld [wLives+0], a
+	ld [wLives], a
 
-	ld a, 0
-	ld [wScore+0], a
+	xor a
+	ld [wScore], a
 	ld [wScore+1], a
 	ld [wScore+2], a
 	ld [wScore+3], a
@@ -44,7 +44,7 @@ InitGameplayState::
     call DrawTextTilesLoop
 
 	; Call Our function that draws text onto background/window tiles
-    ld de, $9c0D
+    ld de, $9c0d
     ld hl, wLivesText
     call DrawTextTilesLoop
 	
@@ -64,7 +64,7 @@ InitGameplayState::
 	ld a, LCDCF_ON  | LCDCF_BGON|LCDCF_OBJON | LCDCF_OBJ16 | LCDCF_WINON | LCDCF_WIN9C00|LCDCF_BG9800
 	ld [rLCDC], a
 
-    ret;
+    ret
 ; ANCHOR_END: init-gameplay-state
 	
 ; ANCHOR: update-gameplay-state-start
@@ -102,7 +102,7 @@ UpdateGameplayState::
 
 ; ANCHOR: update-gameplay-end-update
 	ld a, [wLives]
-	cp a, 250
+	cp 250
 	jp nc, EndGameplay
 
 	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -127,4 +127,4 @@ EndGameplay:
     ld a, 0
     ld [wGameState],a
     jp NextGameState
-; ANCHOR_END: update-gameplay-end-update
+; ANCHOR_END: update-gameplay-end-update

galactic-armada/src/main/states/gameplay/hud.asm

@@ -18,19 +18,18 @@ IncreaseScore_Loop:
     ld [hl], a
 
     ; Stop if it hasn't gone past 0
-    cp a, 9
+    cp 9
     ret c
 
 ; If it HAS gone past 9
 IncreaseScore_Next:
 
     ; Increase a counter so we can not go out of our scores bounds
+    inc c
     ld a, c
-    inc a 
-    ld c, a
 
-    ; Check if we've gone our o our scores bounds
-    cp a, 6
+    ; Check if we've gone over our scores bounds
+    cp 6
     ret z
 
     ; Reset the current digit to zero
@@ -50,7 +49,7 @@ DrawLives::
     ld de, $9C13 ; The window tilemap starts at $9C00
 
     ld a, [hl]
-    add a, 10 ; our numeric tiles start at tile 10, so add to 10 to each bytes value
+    add 10 ; our numeric tiles start at tile 10, so add 10 to each bytes value
     ld [de], a
 
     ret
@@ -68,13 +67,11 @@ DrawScore::
 DrawScore_Loop:
 
     ld a, [hli]
-    add a, 10 ; our numeric tiles start at tile 10, so add to 10 to each bytes value
+    add 10 ; our numeric tiles start at tile 10, so add to 10 to each bytes value
     ld [de], a
 
     ; Decrease how many numbers we have drawn
-    ld a, c
-    dec a
-    ld c, a
+    dec c
 		
     ; Stop when we've drawn all the numbers
     ret z
@@ -83,4 +80,4 @@ DrawScore_Loop:
     inc de
 
     jp DrawScore_Loop
-; ANCHOR_END: hud-draw-score
+; ANCHOR_END: hud-draw-score

galactic-armada/src/main/states/gameplay/interrupts.asm

@@ -5,7 +5,7 @@ INCLUDE "src/main/utils/hardware.inc"
  SECTION "Interrupts", ROM0
 
  DisableInterrupts::
-	ld a, 0
+	xor a
 	ldh [rSTAT], a
 	di
 	ret
@@ -14,7 +14,7 @@ InitStatInterrupts::
 
     ld a, IEF_STAT
 	ldh [rIE], a
-	xor a, a ; This is equivalent to `ld a, 0`!
+	xor a
 	ldh [rIF], a
 	ei
 
@@ -24,7 +24,7 @@ InitStatInterrupts::
 
 	; We'll start with the first scanline
 	; The first stat interrupt will call the next time rLY = 0
-	ld a, 0
+	xor a
 	ldh [rLYC], a
 
     ret
@@ -39,13 +39,13 @@ StatInterrupt:
 
 	; Check if we are on the first scanline
 	ldh a, [rLYC]
-	cp 0
+	and a
 	jp z, LYCEqualsZero
 
 LYCEquals8:
 
 	; Don't call the next stat interrupt until scanline 8
-	ld a, 0
+	xor a
 	ldh [rLYC], a
 
 	; Turn the LCD on including sprites. But no window
@@ -70,4 +70,4 @@ EndStatInterrupts:
 	pop af
 
 	reti;
-; ANCHOR_END: interrupts-section
+; ANCHOR_END: interrupts-section