Moved spiral warp point during dark transition (fixed $53 logic)

More spiral layers fixed by adding a 'from layer' bit.
Several edge cases addressed (a couple stairs crossed quadrant boundaries during transition)

asm/spiral.asm

@@ -1,12 +1,18 @@
+RecordStairType: {
+    lda $0e : sta $045e
+    lda $a0 : lda $063d, x
+    rtl
+}
+
 SpiralWarp: {
-    pha : lda $040c : cmp.b #$ff : beq .abort ; abort if not in dungeon
+    lda $040c : cmp.b #$ff : beq .abort ; abort if not in dungeon
     cmp #$06 : bcs .abort ; abort if not supported yet -- todo: this needs to be altered/removed as more dungeons are implemented
-    lda $0e : cmp #$5e : beq .gtg ; abort if not spiral - intended room is in A!
+    lda $045e : cmp #$5e : beq .gtg ; abort if not spiral - intended room is in A!
     cmp #$5f : beq .gtg
-    .abort pla : sta $a0 : bra .end
+    .abort
+    lda $a2 : and #$0f : rtl ; run highjack code and get out
 
     .gtg
-    pla
     phb : phk : plb : phx : phy ; push stuff
     jsr LookupSpiralOffset
     rep #$30 : and #$00FF : asl #2 : tax
@@ -28,9 +34,15 @@ SpiralWarp: {
 
     .skipYQuad
     lda $01 : and #$04 : lsr : sta $048a ;fix layer calc 0->0 2->1
+    lda $01 : and #$08 : lsr #2 : sta $0492 ;fix from layer calc 0->0 2->1
     ; shift lower coordinates
-    lda $02 : sta $22
-    lda $03 : sta $20
+    lda $02 : sta $22 : bne .adjY : inc $23
+    .adjY lda $03 : sta $20 : bne .set53 : inc $21
+    .set53 ldx #$08
+    lda $0462 : and #$04 : beq .upStairs
+    ldx #$fd
+    .upStairs
+    txa : !add $22 : sta $53
 
     lda $01 : and #$10 : sta $07 ; zeroHzCam check
     ldy #$00 : jsr SetCamera
@@ -38,12 +50,8 @@ SpiralWarp: {
     ldy #$01 : jsr SetCamera
 
     ply : plx : plb ; pull the stuff we pushed
-
-    .end rtl
-    ; this is the code we are hijacking
-    ; lda $a0 - we overwrote all this behavior
-    ; lda $063d, x
-    ; sta $048a
+    lda $a2 : and #$0f ; this is the code we are hijacking
+    rtl
 }
 
 ;Sets the offset in A
@@ -86,7 +94,9 @@ LookupSpiralOffset: {
 
 ShiftQuadSimple: {
 	lda CoordIndex,y : tax
+	lda $20,x : beq .skip
 	lda $21,x : !add $06 : sta $21,x ; coordinate update
+	.skip
 	lda CamQuadIndex,y : tax
 	lda $0601,x : !add $06 : sta $0601,x
 	lda $0605,x : !add $06 : sta $0605,x ; high bytes of these guys
@@ -94,8 +104,7 @@ ShiftQuadSimple: {
 }
 
 SetCamera: {
-    stz $04 : sty $05
-
+    stz $04
     tyx : lda $a9,x : bne .nonZeroHalf
     lda CamQuadIndex,y : tax : lda $607,x : pha
     lda CameraIndex,y : tax : pla : cmp $e3, x : bne .noQuadAdj
@@ -104,27 +113,30 @@ SetCamera: {
     .noQuadAdj
     lda $07 : bne .adj0
     lda CoordIndex,y : tax
-    lda $20,x : cmp #$79 : bcc .adj0
+    lda $20,x : beq .oddQuad
+    cmp #$79 : bcc .adj0
     !sub #$78 : sta $04
     tya : asl : !add #$04 : tax : jsr AdjCamBounds : bra .done
+    .oddQuad
+    lda #$80 : sta $04 : bra .adj1 ; this is such a weird case - quad cross boundary
     .adj0
     tya : asl : tax : jsr AdjCamBounds : bra .done
 
     .nonZeroHalf ;meaning either right half or bottom half
+    lda $07 : bne .setQuad
     lda CoordIndex,y : tax
     lda $20,x : cmp #$78 : bcs .setQuad
-    lda $07 : bne .adj1
     !add #$78 : sta $04
+    .adj1
     tya : asl : !add #$08 : tax : jsr AdjCamBounds : bra .done
 
     .setQuad
     lda CamQuadIndex,y : tax : lda $0607, x : pha
     lda CameraIndex,y : tax : pla : sta $e3, x
-    .adj1
     tya : asl : !add #$0c : tax : jsr AdjCamBounds : bra .done
 
     .done
-    lda CameraIndex,y : tax : lda $e2, x
+    lda CameraIndex,y : tax
     lda $04 : sta $e2, x
     rts
 }