optimized crunch with crash mode accommodated

Author: zohassadar

src/modes/crunch.asm

@@ -17,66 +17,66 @@
 ; F - 3 left 3 right
 
 advanceGameCrunch:
-    lda #0
-    sta vramRow
-    lda #20
-advanceSides:
-    pha
-    sta tmp3
+; initialize vars
     lda crunchModifier
-    lsr a
-    lsr a
-    ldx #0
-    jsr advanceSide
-    pla
-    sta tmp3
+    lsr
+    lsr
+    sta crunchLeftColumns
     lda crunchModifier
-    and #%00000011
-    pha
-    eor #$FF
-    sec
-    adc #0
+    and #$03
     clc
-    adc #10
-    tax
-    pla
-    jsr advanceSide
+    adc crunchLeftColumns ; carry still clear
+    eor #$FF
+    adc #$0B ; 10 + 1 to get two's complement.  result is playable column count
+    sta crunchClearColumns
+
+; initialize playfield row 19 to 0
+    lda #$13
+    sta generalCounter
+@nextRow:
+    jsr advanceSidesInit
+    dec generalCounter
+    bpl @nextRow
+
+; restore playfieldAddr and set vramRow for rendering
+    lda #$00
+    sta vramRow
+    sta playfieldAddr
+crunchReturn:
     rts
 
-advanceSide:
-    cmp #0
-    beq @end
-    pha
-    ldy #0
-    txa
-    clc
-    adc #<playfield
-    sta tmp1
-    lda #>playfield
-    sta tmp2
-@rowLoop:
-    pla
-    pha
-    tax
-    beq @end
-@blockLoop:
+; for init only.  row determined by generalCounter
+advanceSidesInit:
+    ldy generalCounter
+    lda multBy10Table,y
+    sta playfieldAddr
+
+; after init, only top row is drawn.  using (playfieldAddr),y defaults to top row
+; as playfieldAddr is 0 when this is called (and most of the time)
+advanceSides:
+    ldy #$00
     lda #BLOCK_TILES
-    sta (tmp1), y
-    inc tmp1
+
+; x controls left tile count.  x can start at 0,1,2 or 3.
+    ldx crunchLeftColumns
+@leftLoop:
     dex
-    bne @blockLoop
-    pla
-    pha
-    eor #$FF
-    sec
-    adc #0
-    clc
-    adc tmp1
+    bmi @right
+    sta (playfieldAddr),y
+    iny
+    bne @leftLoop ; unconditional
+
+@right:
+    tya
     clc
-    adc #10
-    sta tmp1
-    dec tmp3
-    bne @rowLoop
-    pla
-@end:
-    rts
+    adc crunchClearColumns
+    tay
+    lda #BLOCK_TILES
+
+; y is replaced with crunchClearColumns + y and increments until y == 10.  y can start at 7,8,9 or 10.
+@rightLoop:
+    cpy #$0A
+    beq crunchReturn
+    sta (playfieldAddr),y
+    iny
+    bne @rightLoop ; unconditional

src/playstate/completedrows.asm

@@ -144,7 +144,6 @@ playState_checkForCompletedRows:
         lda practiseType
         cmp #MODE_CRUNCH
         bne @crunchEnd
-        lda #1
         jsr advanceSides
 @crunchEnd:
 

src/playstate/util.asm

@@ -81,6 +81,18 @@ updateMusicSpeed:
         ldx #$05
         lda multBy10Table,x ;this piece of code is parameterized for no reason but the crash checking code relies on the index being 50-59 so if you ever optimize this part out of the code please also adjust the crash test, specifically the part which handles cycles for allegro.
         tay
+
+; check if crunch mode
+        lda practiseType
+        cmp #MODE_CRUNCH
+        bne @notCrunch
+
+        ; start at first clear column and repeat only for playable columns
+        ldy crunchLeftColumns
+        ldx crunchClearColumns
+        bne @checkForBlockInRow ; unconditional, expected range 4 - 10
+
+@notCrunch:
         ldx #$0A
 @checkForBlockInRow:
         lda (playfieldAddr),y

src/ram.asm

@@ -220,8 +220,10 @@ dasOnlyShiftDisabled: .res 1 ; $63A
 invisibleFlag: .res 1 ; $63B  ; 0 for normal mode, non-zero for Invisible playfield rendering.  Reset on game init and game over.
 currentFloor: .res 1 ; $63C floorModifier is copied here at game init.  Set to 0 otherwise and incremented when linecap floor.
 mapperId: .res 1 ; $63D ; For INES_MAPPER 1000 (autodetect).  0 = CNROM.  1 = MMC1.
+crunchLeftColumns: .res 1
+crunchClearColumns: .res 1 ; playable column count
 
-    .res $37
+    .res $35
 
 .if KEYBOARD
 newlyPressedKeys: .res 1 ; $0675