;z80
;zx-spectrum
;assembler

; hrust decompressor
; Copyright (c) 1999 Dmitry Pyankov

	ld a,(hl)
	inc hl
	cp 0x68
	ret nz
	ld a,(hl)
	inc hl
	cp 0x72
	ret nz
	ld a,(hl)
	inc hl
	cp 0x32
	ret nz
	ld a,(hl)
	inc hl
	rla
	ex af,af'
	push de
	ld c,(hl)
	inc hl
	ld b,(hl)
	inc hl
	dec bc
	ex de,hl
	add hl,bc
	ex de,hl
	ld c,(hl)
	inc hl
	ld b,(hl)
	add hl,bc
	sbc hl,de
	add hl,de
	jr c,dehrust_27
	ld d,h
	ld e,l
dehrust_27	push bc
	lddr
	pop bc
	ex de,hl
	ex af,af'
	jr nc,dehrust_34
	pop de
	inc hl
	ldir
	ret
dehrust_34	ld de,0x0007
	add hl,de
	push hl
	exx
	pop hl
	pop de
	ld a,0x03
dehrust_3e	dec hl
	ld b,(hl)
	dec hl
	ld c,(hl)
	push bc
	dec a
	jr nz,dehrust_3e
	ld b,a
	exx
	ld de,0x1003
	ld c,0x80
dehrust_4d	ld a,(hl)
	inc hl
	exx
	ld (de),a
	inc de
dehrust_52	exx
dehrust_53	sla c
	jr nz,dehrust_5b
	ld c,(hl)
	inc hl
	rl c
dehrust_5b	jr c,dehrust_4d
	ld b,0x01
dehrust_5f	ld a,0x40
dehrust_61	sla c
	jr nz,dehrust_69
	ld c,(hl)
	inc hl
	rl c
dehrust_69	rla
	jr nc,dehrust_61
	cp e
	jr c,dehrust_74
	add a,b
	ld b,a
	xor d
	jr nz,dehrust_5f
dehrust_74	add a,b
	cp 0x04
	jr z,dehrust_c6
	adc a,0xff
dehrust_7b	cp 0x02
dehrust_7d	exx
	ld c,a
	ld h,0xff
	exx
	jr c,dehrust_e0
	jr z,dehrust_af
	sla c
	jr nz,dehrust_8e
	ld c,(hl)
	inc hl
	rl c
dehrust_8e	jr c,dehrust_af
	ld a,0x7f
	ld b,e
	djnz dehrust_e2
dehrust_95	djnz dehrust_b8
	ld b,a
	sbc a,a
dehrust_99	sla c
	jr nz,dehrust_a1
	ld c,(hl)
	inc hl
	rl c
dehrust_a1	rla
	dec a
	inc b
	jr nz,dehrust_99
	cp 0xe1
	jr nz,dehrust_ac
	ld a,(hl)
	inc hl
dehrust_ac	exx
	ld h,a
	exx
dehrust_af	ld a,(hl)
	inc hl
dehrust_b1	exx
	ld l,a
	add hl,de
	ldir
	jr dehrust_52
dehrust_b8	add a,0x06
	rla
	ld b,a
dehrust_bc	ld a,(hl)
	inc hl
	exx
	ld (de),a
	inc de
	exx
	djnz dehrust_bc
	jr dehrust_53
dehrust_c6	sla c
	jr nz,dehrust_ce
	ld c,(hl)
	inc hl
	rl c
dehrust_ce	ld a,d
	jr nc,dehrust_e2
	ld a,(hl)
	inc hl
	cp d
	jr nc,dehrust_7b
	or a
	jr z,dehrust_f1
	exx
	ld b,a
	exx
	ld a,(hl)
	inc hl
	jr dehrust_7d
dehrust_e0	ld a,0x3f
dehrust_e2	sla c
	jr nz,dehrust_ea
	ld c,(hl)
	inc hl
	rl c
dehrust_ea	rla
	jr nc,dehrust_e2
	djnz dehrust_95
	jr dehrust_b1
dehrust_f1	ld hl,0x2758
	exx
	ld b,0x03
	ex de,hl
dehrust_f8	pop de
	ld (hl),e
	inc hl
	ld (hl),d
	inc hl
	djnz dehrust_f8
	ret