;test

;
; Joyce screen dump using ESC L n1 n2 to give about 3/4 width dump
;
; program by Cliff Lawson, 1986 Amstrad Consumer Electronics plc.
;
; This is inplemented as a null .COM file with attached RSX that is set
; to renain in memory. It intercepts BOOS function 2 and if an escape
; character is printed then the dump springs into life. Two types of dump
; are supported. ESC O gives a heavy print while ESC P is more of a "draft"
; quality dump. The heavy one works by printing the info, once, performing
; a fractional line feed then overprinting followed by the rest of a conplete
; line feed.
; A new BDOS call 73 (as always) is implemented so that the RSX can be
; removed.
;
; Use  RMAC B:JOYCEDMP $PZSZRM
;      LINK M:JOYCEDMP[OP $SZRB]
;      REN JOYCEDMP.RSX=JOYCEDMP.PRL
;      GENCOM B:JOYCEDMP [NULL]
;

bdos		equ	5
listout		equ	5
cr		equ	00dh
lf		equ	00ah
esc		equ	27
heavy		equ	'O'
light		equ	'P'
offsetuserf	equ	87
scrrunroutine	equ	00e9h
bytesperline	equ	720
roller		equ	0b600h

ldir	macro
	db	0edh,0b0h
	endm

	db	0,0,0,0,0,0	;'ole faithful RSX prefix
	jmp	start
next:	db	0c3h
	dw	0		;next chain entry filled by LOADER
prev:	dw	0		;previous entry     "    "    "
remov:	db	000h		;leave in memory
nbank:	db	0		;not non-banked
	db	'SCRNDMP'
loader:	db	0
	db	0,0

start
	mov	a,c
	cpi	2
	jz	begin
	cpi	73
	jz	takeaway
	jmp	next

takeaway
	mvi	a,0ffh
	sta	remov
	ret

begin
	lda	flagesc
	cpi	0ffh
	jz	contest		;just had an escape
	mov	a,e
	cpi	esc		;escape O or P Starts dunp
	jz	setflag
	jmp	next		;nothing to do with us

setflag
	mvi	a,0ffh
	sta	flagesc
	ret

contest
	mov	a,e
	cpi	heavy		;heavy dump
	jz	goforit
	cpi	light		;light dump
	jz	goforit
	xra	a
	sta	flagesc		;forget that last ESC
	push	d
	push	b
	mvi	c,2
	mvi	e,esc
	call	next		;but esc wasn't ours so make awends
	pop	b
	pop	d
	jmp	next		;pass current char down the thain

goforit
	sta	dtype		;save 'O' or 'P' that deterwine dump type
	xra	a
	sta	flagesc		;esc has been used so reset

	lxi	h,0
	dad	sp
	shld	oldstak		;save CCP stack
	lxi	sp,mystak	;use my own 64 byte stack

	lhld	1
	lxi	d,offsetuserf
	dad	d
	shld	userf+1		;that famous ole routine

	mvi	a,esc
	call	prntbyte
	mvi	a,'3'	
	call	prntbyte
	mvi	a,25		;fiddle factor
	call	prntbyte

	mvi	a,0		;start at line 0
dloop	
	push	psw		;keep line count safe
dark
	push	psw		;save line count while sussin lf setting

	lda	dtype
	cpi	light
	jz	fred
	mvi	a,esc		;only set this fractional line feed lf
	call	prntbyte	;we're going to overtype for heavy dump
	mvi	a,'3'
	call	prntbyte
	mvi	a,2
	call	prntbyte	;set first line feed to 2/216"
fred
	pop	psw		;ok to retrieve line count for grabyte
	lxi	b,grabyte
	call	userf
	dw	scrrunroutine
	call	dumpaline
	lda	dtype
	cpi	light
	jz	justone		;If ESC P then dont do line again
	mvi	a,esc		;second pass, lf now to be set to 23/216"
	call	prntbyte
	mvi	a,'3'
	call	prntbyte
	mvi	a,23		;previous 2/216 + 23/216 = 25/216
	call	prntbyte
	pop	psw
	push	psw		;what was that line count ?
	lxi	b,grabyte	;need to grab bytes cos dump is destructive
	call	userf
	dw	scrrunroutine
	call	dumpaline	;overtype what's just been printed
justone
	mvi	c,6
	mvi	e,0ffh
	call	next		;attempt to get keyboard char
	cpi	0
	jnz	pleasereleaseme
	pop	psw		;let's have that line count back again
	inr	a
	cpi	32		;done line 31 yet ?
	jnz	dloop
eric
	lda	dtype
	cpi	light
	jz	dontreset	;cos it hasn't changed
	mvi	a,esc
	call	prntbyte
	mvi	a,'2'		;set line feed Back to 1/6"
	call	prntbyte
dontreset
	lhld	oldstak		;let Mr. CCP have his own stack back
	sphl
	ret			;an ave it away an our toes

pleasereleaseme		
	pop	psw		;don't you just luv a bit of structure ?
	jmp	eric

;=======
grabyte			
;=======
;
; Go get one lines worth of bytes fror screen memory
;
; entry : a contains the character line number
; exit  : all corrupt
;
	mov	e,a
;
;The following is a routine whith already sits in common memory
; and is executed by scr_run_routine
;
; this routine courtesy Roland Perry
;
; entry conditions:
;
;    e=line number
;
docommon:
	lxi	h,buffer
	push	h
	mvi	h,0
	mov	l,e		;hl=e
	dad	h		;hl=2*e
	dad	h		;hl=4*e
	dad	h		;hl=8*e
	dad	h		;hl=16*e
	lxi	d,roller	;that mysterious region of the universe
	dad	d		;hl=roller+16+e
;
	mov	e,m
	inx	h
	mov	d,m		;de=encoded address
;
	mov	a,e
	ani	7		;also clears carry
	mov	l,a		;l = 3 lsb
	mov	a,e
	ral			;lp8 to carry
	mov	e,a		;lp7-4/lp2-lp0/carry
	mov	a,d
	ral			;lsb=lp8
	mov	d,a
	mov	a,e
	ani	0F0h		;lp7-lp4
	ora	l
	mov	e,a		;don't you just love meaningful comments
;
	pop	h
	lxi	b,bytesperline
	xchg			;move from screen to buffer
	ldir
	ret
;

;=========
dumpaline:
;=========
;
; Dump one lines worth of byte to printer. There are 90 characters each
; composed of eight bytes so HL points at buffer containing 720 bytes.
;
; entry : no conditions	
; exit  : all registers corrupt	
;         (and Buffer contents destroyed)
;
	lxi	h,buffer
	mvi	a,esc		;let Mr. printer know whats happening
	call	prntbyte
	mvi	a,'L'
	call	prntbyte
	mvi	a,(bytesperline	and 0ffh)
	call	prntbyte
	mvi	a,(bytesperline/256)
	call	prntbyte

	mvi	b,0		;character count (0..89)
dstart
	push	b
	mvi	b,8		;number of shifts count (8)
ateshft
	xra	a		;clear A and carry
	mvi	c,8		;number of bytes in a group (8)
	push	h
atebit
	db	0cbh,026h	;Z80 SLA (HL)
				;drawback of this is that it can't be single
				;stepped in SID. So put NOP after to hold a
				;RST 6 if needed
;	nop
	ral			;so the 8080 does have rotates after all
	inx	h
	dcr	c
	jnz	atebit		;have we got all 8 top bits ?
	call	prntbyte	;yup, so print that character
	pop	h
	dcr	b
	jnz	ateshft		;have the current group been shifted 8 times
	lxi	d,8
	dad	d		;step hl onto next group of 8
	pop	b
	inr	b
	mov	a,b
	cpi	90		;hit the 90th group of 8 yet ?
	jnz	dstart
	mvi	a,cr		;Guess it uould be a guod idea to start
	call	prntbyte	;next line at l.h. margin
	mvi	a,lf
	call	prntbyte	;either 2/216,23/216 or just 25/216
	ret

prntbyte
	push	h
	push	d
	push	b
	mov	e,a
	mvi	c,listout
	call	bdos
	pop	b
	pop	d
	pop	h
	ret

userf:	db	0c3h 		;what do you mean you've never heard of it
	dw	0

	dseg

flagesc	db	0
dtype	db	0

oldstak	dw	0

buffer	ds	720
	ds	64
mystak

	end