1 files changed, 130 insertions, 0 deletions
diff --git a/engine/battle/b_2.asm b/engine/battle/b_2.asm
new file mode 100755
index 00000000..b71ca40d
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+++ b/engine/battle/b_2.asm
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+; scales both uncompressed sprite chunks by two in every dimension (creating 2x2 output pixels per input pixel)
+; assumes that input sprite chunks are 4x4 tiles, and the rightmost and bottommost 4 pixels will be ignored
+; resulting in a 7*7 tile output sprite chunk
+ScaleSpriteByTwo: ; 2fe40 (b:7e40)
+	ld de, S_SPRITEBUFFER1 + (4*4*8) - 5          ; last byte of input data, last 4 rows already skipped
+	ld hl, S_SPRITEBUFFER0 + SPRITEBUFFERSIZE - 1 ; end of destination buffer
+	call ScaleLastSpriteColumnByTwo               ; last tile column is special case
+	call ScaleFirstThreeSpriteColumnsByTwo        ; scale first 3 tile columns
+	ld de, S_SPRITEBUFFER2 + (4*4*8) - 5          ; last byte of input data, last 4 rows already skipped
+	ld hl, S_SPRITEBUFFER1 + SPRITEBUFFERSIZE - 1 ; end of destination buffer
+	call ScaleLastSpriteColumnByTwo               ; last tile column is special case
+
+ScaleFirstThreeSpriteColumnsByTwo: ; 2fe55 (b:7e55)
+	ld b, $3 ; 3 tile columns
+.columnLoop
+	ld c, 4*8 - 4 ; $1c, 4 tiles minus 4 unused rows
+.columnInnerLoop
+	push bc
+	ld a, [de]
+	ld bc, -(7*8)+1       ; $ffc9, scale lower nybble and seek to previous output column
+	call ScalePixelsByTwo
+	ld a, [de]
+	dec de
+	swap a
+	ld bc, 7*8+1-2        ; $37, scale upper nybble and seek back to current output column and to the next 2 rows
+	call ScalePixelsByTwo
+	pop bc
+	dec c
+	jr nz, .columnInnerLoop
+	dec de
+	dec de
+	dec de
+	dec de
+	ld a, b
+	ld bc, -7*8 ; $ffc8, skip one output column (which has already been written along with the current one)
+	add hl, bc
+	ld b, a
+	dec b
+	jr nz, .columnLoop
+	ret
+
+ScaleLastSpriteColumnByTwo: ; 2fe7d (b:7e7d)
+	ld a, 4*8 - 4 ; $1c, 4 tiles minus 4 unused rows
+	ld [H_SPRITEINTERLACECOUNTER], a ; $ff8b
+	ld bc, -1 ; $ffff
+.columnInnerLoop
+	ld a, [de]
+	dec de
+	swap a                    ; only high nybble contains information
+	call ScalePixelsByTwo
+	ld a, [H_SPRITEINTERLACECOUNTER] ; $ff8b
+	dec a
+	ld [H_SPRITEINTERLACECOUNTER], a ; $ff8b
+	jr nz, .columnInnerLoop
+	dec de                    ; skip last 4 rows of new column
+	dec de
+	dec de
+	dec de
+	ret
+
+; scales the given 4 bits in a (4x1 pixels) to 2 output bytes (8x2 pixels)
+; hl: destination pointer
+; bc: destination pointer offset (added after the two bytes have been written)
+ScalePixelsByTwo: ; 2fe97 (b:7e97)
+	push hl
+	and $f
+	ld hl, DuplicateBitsTable
+	add l
+	ld l, a
+	jr nc, .noCarry
+	inc h
+.noCarry
+	ld a, [hl]
+	pop hl
+	ld [hld], a  ; write output byte twice to make it 2 pixels high
+	ld [hl], a
+	add hl, bc   ; add offset
+	ret
+
+; repeats each input bit twice
+DuplicateBitsTable: ; 2fea8 (b:7ea8)
+	db $00, $03, $0c, $0f
+	db $30, $33, $3c, $3f
+	db $c0, $c3, $cc, $cf
+	db $f0, $f3, $fc, $ff
+
+PayDayEffect_ ; 2feb8 (b:7eb8)
+	xor a
+	ld hl, $cd6d
+	ld [hli], a
+	ld a, [$fff3]
+	and a
+	ld a, [$d022]
+	jr z, .asm_2fec8 ; 0x2fec3 $3
+	ld a, [$cff3]
+.asm_2fec8
+	add a
+	ld [$ff98], a
+	xor a
+	ld [$ff95], a
+	ld [$ff96], a
+	ld [$ff97], a
+	ld a, $64
+	ld [$ff99], a
+	ld b, $4
+	call Divide
+	ld a, [$ff98]
+	ld [hli], a
+	ld a, [$ff99]
+	ld [$ff98], a
+	ld a, $a
+	ld [$ff99], a
+	ld b, $4
+	call Divide
+	ld a, [$ff98]
+	swap a
+	ld b, a
+	ld a, [$ff99]
+	add b
+	ld [hl], a
+	ld de, $cce7
+	ld c, $3
+	ld a, $b
+	call Predef
+	ld hl, CoinsScatteredText ; $7f04
+	jp PrintText
+
+CoinsScatteredText: ; 2ff04 (b:7f04)
+	TX_FAR _CoinsScatteredText
+	db "@"