; CALCRCP.Z80 Version 1.0          
; October 31, 1986 by Carson Wilson.       
;
; Please leave any problems, comments, or suggestions at
; Lillipute Z-Node, Chicago, 312-649-1730 or 312-664-1730.
;
; This is a combination of elements from Paul Pomerleau's
; SLTRAP.LBR and Eric Meyer's HP.COM. When assembled into a
; Resident Command Package (RCP) for ZCPR3, it becomes a "pop-up"
; calculator modelled on the principles of Eric Meyer's HP+.COM
; for CP/M Plus.
;
; To use, first put this file and Z3BASE.LIB for your system on
; the current drive and assemble and load to CALC.RCP. Then load
; CALC.RCP with LDR.COM. Use the "H" command to display help on
; usage. The calculator won't become active until activated by
; the command "CALC" from your system's operating system prompt. 
; Thereafter, whenever a CONTROL-] is detected, the calculator
; will become active. The calculator can thus be activated from
; the middle of any program which tests for console input, which
; means any interactive program. 

; WARNING: BECAUSE THIS RCP LINKS UP WITH YOUR SYSTEM'S BIOS, IT
; IS NECESSARY TO TURN IT OFF BY USING THE "CALC" COMMAND AGAIN
; BEFORE LOADING ANOTHER RCP. 

; To make the CALC.RCP even more versatile, create an alias named
; RCP.COM which will respond to commands to automatically go to
; the proper directories, get the proper RCP and load it.

; For example, my CALC.COM contains the following:

; IF EX LOAD:$1.RCP
; ROOT:LDR LOAD:$1.RCP
; FI
; H

; This enables me to type "RCP CALC," thereby commanding my
; system to get CALC.RCP from the proper directory, load it, and
; display its built-in help. When I'm through with CALC, I first type
; CALC to turn it off, then "RCP SYS" to reload my normal RCP. 

; Like HP+.COM, this calculator may not work with a very few
; programs such as WordStar, which interact directly with the
; BIOS. See HP+.DOC for more on this. For information on how the
; calculator works, see HP.DOC by Eric Meyer. Both of these files
; are found in HP.LBR.

vers	equ	10  
BDOS	equ	5

maclib	Z3Base.lib	; use base addresses

;
; System entry point
;
	org	RCP		; Passed from Z3Base
	db	'Z3RCP'		; Flag for package loader
	db	04		; How long each name is
ctab:
	db	'H   '	; Help for RCP
	dw	CList
	db	'CALC'	; Enable/Disable trigger key
	dw	TrigOn
ctab1:
	db	0
;
;  Banner name of RCP:
;  Command list routine
;
CList:
	ld	de,RCP$name
	jp	string
;
; Routines for trapping I/O.
;
Trigger	equ	']'-'@'	; control-] is current trigger key
;
TrigOn:	ld	a,(IsOn)
	cp	1		; key detection on?
	jp	z,TrigOff	; yes, turn off
	ld	a,1		; no, flip flag to ON
	ld	(IsOn),a	; & fall through  
;
; ENABLE Trigger Key Detection
;
; First, replace BIOS jump to its "console in" routine with jump
; to RCP routine, and save the addresses of the BIOS jump and the
; routine. 
;
	ld	hl,(1)		; Get boot location
	ld	de,07h		; Offset for location of "JP CONIN" in BIOS
	add	hl,de		; hl now holds BIOS "jump" location
	ld	(JConIn),hl	; Save location for BIOS jp to console in
	ld	e,(hl)
	inc	hl
	ld	d,(hl)		; Move to de
	ld	(ConIn),de	; Save BIOS ConIn routine address
	ld	de,NewIn
	ld	(hl),d		; Replace BIOS "jump" with ours
	dec	hl
	ld	(hl),e		; Fill our NewIn location in
;
; Now save the address of the BIOS conout routine.
;
  	ld	hl,(1)		; Get boot location
  	ld	de,0ah		; Offset for location of "JP CONOUT" in BIOS
  	add	hl,de		; hl now holds BIOS "jump" location 
  	ld	e,(hl)
  	inc	hl
 	ld	d,(hl)		; Move to de
	ld	(con),de	; Save BIOS ConOut routine address
;
	ld	a,(on)		; Is the calculator running?
	or	a
	ret	nz 		; Yes, don't print "Trigger Key Enabled" msg.
	ld	de,OnMsg	; Else tell user trigger key activated
	jp	string
	ret
;
NewIn:	call	OrigIn		; Bring key in
      	cp	Trigger		; Is it the trigger key?
	ret	nz		; No - business as usual 
;
	ld	(SavStk),sp	; Yes, run calculator
	ld	sp,newstk
;
	push	ix
	push	iy	
	push	af
	push	bc
	push	de
	push	hl	
;
	ld	a,(on)
	cpl	
	ld	(on),a		; Flip calculator running flag
;
	call	TrigOff		; Turn off trigger key detection
				; and fall through to calculator

;
; ********** Begin Calculator *********
;
; This is a modified disassembly of HP.COM by Eric Meyer.  In place
; of the HP prompt, I have substituted a more informative one. 
; Relative jumps are substituted for absolute ones where possible. 
; The exit and entry routines have been replaced by my own routines
; which appear immediately before and after the calculator routine.
; The exit key has been changed from ^C to ^] to maintain
; consistency with the trigger key.  Finally, direct BIOS calls
; replace BDOS calls to conin and conout, and a routine which
; replaces echoed characters from BDOS conin is no longer
; necessary (commented out).
;
	jr	start
signon:	db	0dh,'CALC-RCP (^] = Off)   '
	db	'         ',0
	ld	a,(de)
start:	xor	a
  	ld	(r17),a
s9:	ld	hl,signon
	call	StrOut
	call	s2
	ld	hl,(r4)
	call	s3
	ld	hl,r5
	ld	b,8		; Print 8 spaces 
prompt:	ld	(hl),' '
	inc	hl
	dec	b
	jr	nz,prompt
	ld	hl,r5		; Print prompt "H>"
	call	StrOut
	xor	a
	ld	(r3),a
getin:	call	s4	; Get input from BIOS 
	cp	Trigger	; RCP trigger key
	jp	z,quit	; End program
	cp	1bh
	jp	z,esc
	cp	'+'
	jp	z,plus
	cp	'-'
	jp	z,minus
	cp	'*'
	jp	z,times
	cp	'^'
	jp	z,exp
	cp	'/'
	jp	z,div
	cp	'%'
	jp	z,remain
	cp	'&'
	jp	z,bitand
	cp	'|'
	jp	z,bitor
	cp	'~'
	jp	z,negate
	cp	0dh
	jp	z,run
	cp	8
	jr	z,backsp
	cp	'='
	jp	z,equals
	cp	18h	; ^X
	jr	z,clear
	cp	'S'
	jp	z,save
	cp	's'
	jp	z,save
	cp	'R'
	jp	z,recall
	cp	'r'
	jp	z,recall
	cp	'!'		; Space or control char?
	jp	c,illegal	; Yes - error
s23:	ld	hl,r7
	ld	de,r5
	ld	bc,7
	ldir
	ld	(r8),a
	ld	a,0ffh
	ld	(r3),a
s8:	ld	hl,signon	; Reprint prompt
	call	StrOut
	call	s2
	ld	hl,r5
	call	StrOut
	jp	getin		; Get input
backsp:	ld	a,(r3)
	or	a
	jr	z,s7
	ld	hl,r9
	ld	de,r8
	ld	bc,7
	lddr
	ld	a,' '
	ld	(r5),a
	jr	s8
s7:	ld	hl,0
	ld	(r4),hl
	ld	a,0ffh
	ld	(r17),a
	jp	s9
clear:	ld	hl,r4		; Clear registers 
	ld	b,10h		; (16 bytes)
s10:	ld	(hl),0
	inc	hl
	dec	b
	jr	nz,s10
	jp	s9
run:	call	s11
	call	s12
	ld	a,0ffh
	ld	(r17),a
	jp	s9
equals:	call	s11
	ld	hl,(r4)
	ex	de,hl
	ld	hl,(r10)
	ex	de,hl
	ld	(r10),hl
	ex	de,hl
	ld	(r4),hl
	jp	start
negate:	call	s11
	ld	hl,(r4)
	ld	a,h
	cpl
	ld	h,a
	ld	a,l
	cpl	
	ld	l,a
	inc	hl
	ld	(r4),hl
	jp	start	
bitor:	call	s11
	call	s14
	ld	a,h
	or	d
	ld	h,a
	ld	a,l
	or	e
	ld	l,a
s16:	ld	(r10),hl
	call	s15
	jp	start
bitand:	call	s11	; bitwise and
	call	s14
	ld	a,h
	and	d
	ld	h,a
	ld	a,l
	and	e
	ld	l,a
	jr	s16
remain:	call	s11	; remainder
	call	s14
	call	s17
	jp	c,s18
	ex	de,hl
	jr	s16
div:	call	s11
	call	s14
	call	s17
	jp	c,s18
	jr	s16
times:	call	s11
	call	s14
	call	s19
	jp	c,s18
	jr	s16
exp:	call	s11
	call	s14
	ld	a,d
	or	e
	jr	nz,s20
	ld	hl,1
	jr	s16
s20:	ld	b,d
	ld	c,e
	ld	d,h
	ld	e,l
s21:	dec	bc
	ld	a,b
	or	c
	jr	z,s16
	push	bc
	push	de
	call	s19
	pop	de
	pop	bc
	jp	c,s18
	jr	s21
minus:	call	s11
	call	s14
	sbc	hl,de
	jr	s16
plus:	call	s11
	call	s14
	add	hl,de
	jp	s16
save:	call	s11
	call	s4
	cp	'4'	; Legal register?
	jp	nc,s18
	sub	'1'	; Legal register?
	jp	c,s18
	add	a,a
	ld	e,a
	ld	d,0
	ld	hl,r11
	add	hl,de
	ld	a,(r4)
	ld	(hl),a
	inc	hl
	ld	a,(r12)
	ld	(hl),a
	jp	start
recall:	call	s11
	call	s4
	cp	'4'
	jp	nc,s18
	sub	'1'
	jp	c,s18
	add	a,a
	ld	e,a
	ld	d,0
	ld	hl,r11
	add	hl,de
	ld	a,(r17)
	or	a
	jr	nz,s22
	push	hl
	call	s12
	pop	hl
s22:	ld	a,(hl)
	ld	(r4),a
	inc	hl
	ld	a,(hl)
	ld	(r12),a
	jp	start
chars:	db	'+-*^/%&~=|SsRr'	; Legal commands
esc:	call	s4
	ld	hl,chars
	ld	b,0eh
s24:	cp	(hl)
	jp	z,s23
	inc	hl
	dec	b
	jr	nz,s24
	and	5fh
	push	af
	call	s11
	pop	af
	cp	'H'	; Switch to hex
	jr	z,hex
	cp	'D'	; Switch to decimal 
	jr	z,dec
	cp	'B'	; Switch to binary
	jr	z,bin
	cp	'C'	; Switch to character
	jr	z,char
	jr	s18
hex:	ld	hl,s25
	ld	de,s26
	jr	s27
dec:	ld	hl,s28
	ld	de,s29
	jr	s27
bin:	ld	hl,s30
	ld	de,s31
	jr	s27
char:	ld	hl,s32
	ld	de,s33
s27:	ld	(r13),a
	ld	(scale),hl	; Store current scale = hex, dec, etc.
	ex	de,hl
	ld	(r14),hl
	jp	start
s14:	ld	hl,(r4)
	ex	de,hl
	ld	hl,(r10)
	ret
s11:	ld	a,(r3)
	or	a
	ret	z
	ld	hl,r5
	call	s35
	jr	c,s36	; Illegal - ring bell
	ld	a,(r17)
	or	a
	jr	nz,s37
	push	hl
	call	s12
	pop	hl
s37:	ld	(r4),hl
	xor	a
	ld	(r17),a
	ret
s36:	pop	hl
illegal:ld	a,7	; Ring bell
	call	CharOut
	jp	s8
s18:	ld	a,7
	call	CharOut
	jp	start
s15:	ld	hl,r10
	ld	de,r4
	ld	bc,0eh
	ldir
	ret
s12:	ld	hl,r15
	ld	de,r16
	ld	bc,0eh
	lddr
	ret
s2:	ld	a,(r13)
	call	CharOut
	ld	a,'>'	; Prompt
	call	CharOut
	ld	a,' '	; Prompt: "H> "
	call	CharOut
	ret
s19:	ld	c,l
	ld	b,h
	ld	hl,0
	ld	a,0fh
s40:	push	af
	or	d
	jp	p,s38
	add	hl,bc
	jp	c,s39
s38:	add	hl,hl
	jp	c,s39
	ex	de,hl
	add	hl,hl
	ex	de,hl
	pop	af
	dec	a
	jr	nz,s40
	or	d
	ret	p
	add	hl,bc
	ret
s17:	ld	a,e
	or	d
	jp	z,s41
	ld	c,l
	ld	b,h
	ld	hl,0
	ld	a,10h
	or	a
s43:	ld	(r20),a
	rl	c
	rl	b
	rl	l
	rl	h
	ld	(r21),hl
	sbc	hl,de
	ccf
	jr	c,s42
	ld	hl,(r21)
s42:	ld	a,(r20)
	dec	a
	jr	nz,s43
	ex	de,hl
	rl	c
	ld	l,c
	rl	b
	ld	h,b
	or	a
	ret
s35:	push	hl
s45:	ld	a,(hl)
	or	a
	jr	z,s44
	cp	' '
	jr	nz,s44
	ld	(hl),'0'
	inc	hl
	jr	s45
s44:	pop	hl
    	db	0c3h	; jp
scale:	dw	s25	; Current scale (hex default)
s25:	ld	b,04h
	call	s46
	call	s47
	ret	c
	ld	d,a
	inc	hl
	call	s47
	ret	c
	ld	e,a
	ex	de,hl
	or	a
	ret
s47:	call	s48
	ret	c
	rlca
	rlca
	rlca
	rlca
	inc	hl
	ld	e,a
	call	s48
	ret	c
	add	a,e
	or	a
	ret
s48:	ld	a,(hl)
	and	7fh
	cp	'A'
	jr	c,s49
	and	5fh
	sub	7
s49:	sub	'0'
	jp	m,s41
	cp	10h
	jr	nc,s41
	or	a
	ret
s39:	pop	bc
s41:	scf
	ret
s46:	ld	a,(hl)
	cp	'0'
	jr	nz,s39
	inc	hl
	dec	b
	jr	nz,s46
	or	a
	ret
s28:	ld	b,3
	call	s46
	ld	de,0
	ld	bc,2710h	; constant
	call	s50
	ld	bc,03e8h
	call	s50
	ld	bc,64h
	call	s50
	ld	bc,0ah
	call	s50
	ld	bc,1
	call	s50
	ex	de,hl
	or	a
	ret
s50:	ld	a,(hl)
	cp	':'
	jr	nc,s39
	sub	'0'
	jp	m,s39
	ex	de,hl
	or	a
s52:	jr	z,s51
	add	hl,bc
	jr	c,s39
	dec	a
	jr	s52
s51:	ex	de,hl
	inc	hl
	ret
s30:	ld	b,0
	ld	c,80h
s56:	ld	a,(hl)
	inc	hl
	cp	'0'
	jr	z,s53
	cp	'1'
	jr	z,s54
	jr	s41
s54:	ld	a,b
	or	c
	ld	b,a
s53:	ld	a,c
	cp	1
	jr	z,s55
	rrca
	ld	c,a
	jr	s56
s55:	ld	l,b
	ld	h,0
	or	a
	ret
s32:	ld	b,7
	call	s46
	ld	a,(hl)
	and	7fh
	ld	l,a
	ld	h,0
	or	a
	ret
s3:	db	0c3h	; jp	
r14:	dw	s26
s26:	ld	b,4
	call	s57
	ld	a,h
	call	s58
	ld	a,l
	call	s58
	ret
s58:	push	af
	and	0f0h
	rra
	rra
	rra
	rra
	call	hexout
	pop	af
	and	0fh
	call	hexout
	ret
hexout:	add	a,'0'
	cp	':'		; Arabic number output?
	jp	c,CharOut	; Yes
	add	a,7		; No - get char. A-F for hex output
	jp	CharOut
s57:	ld	a,' '
	call	CharOut
	dec	b
	jr	nz,s57
	ret
s29:	ld	b,3
	call	s57
	ld	c,0
s74:	ld	a,h
	cp	''''
	jr	c,s60
	jr	nz,s61
	ld	a,l
	cp	10h
	jr	c,s60
s61:	inc	c
	ld	de,0d8f0h	; Constant
	add	hl,de
	jr	s74
s60:	ld	a,'0'
	add	a,c
	call	CharOut
	ld	c,0
s63:	ld	a,h
	cp	3
	jr	c,s62
	jr	nz,s75
	ld	a,l
	cp	0e8h
	jr	c,s62
s75:	inc	c
	ld	de,0fc18h	; Constant
	add	hl,de
	jr	s63
s62:	ld	a,'0'
	add	a,c
	call	CharOut
	ld	c,0
s66:	ld	a,h
	or	a
	jr	nz,s64
	ld	a,l
	cp	64h
	jr	c,s65
s64:	inc	c
	ld	de,0ff9ch	;Constant	
	add	hl,de
	jr	s66
s65:	push	af
	ld	a,'0'	;30h
	add	a,c
	call	CharOut
	pop	af
	ld	c,0
s68:	cp	0ah
	jr	c,s67
	inc	c
	sub	0ah
	jr	s68
s67:	push	af
	ld	a,'0'
	add	a,c
	call	CharOut
	pop	af
	add	a,'0'
	call	CharOut
	ret
s31:	ld	c,80h
	ld	b,l
s70:	call	s69
	ld	a,c
	cp	1
	ret	z
	rrca
	ld	c,a
	jr	s70
s69:	ld	a,b
	and	c
	ld	a,'0'
	jr	z,s71
	ld	a,'1'
s71:	call	CharOut
	ret
s33:	ld	b,7
	call	s57
	ld	a,l
	and	7fh
	cp	7fh
	jr	z,s72
	cp	' '
	jr	nc,CharOut
	or	'@'
	jr	s73
s72:	ld	a,'?'
s73:	push	af
	ld	a,8	; Backspace
	call	CharOut
	ld	a,5eh
	call	CharOut
	pop	af
	jr	CharOut
CharOut:
	push	bc
	push	de
	push	hl
	ld	c,a	; Put char. in C, and	
	call	OrigOut	; BIOS console out
	pop	hl
	pop	de
	pop	bc
	ret
StrOut:	xor	a	; Print string
	add	a,(hl)
	ret	z
	push	hl
	call	CharOut
	pop	hl
	inc	hl
	jr	StrOut
s4:	call	OrigIn
	and	7fh	; Strip high bit
;
; Since we are calling BIOS directly, characters are
; no longer echoed to the screen, so they needn't be erased
;
;	cp	'!'	; printable character?
;	ret	c	; yes 
;	push	af	; no- delete present character
;	ld	a,8	; backspace
;	call	CharOut
;	ld	a,' '	; space
;	call	CharOut
;	pop	af
;
	ret
r4:	db	0	; Registers cleared by "^X"
r12:	db	0
r10:	ds	11
r15:	dw	0
r16:	db	0
;
r11:	ds	6
r13:	db	'H'	; Hex scale is default
r5:	db	0
r7:	db	0,0,0,0,0
r9:	db	0
r8:	dw	0
r3:	db	0
r17:	db	0
r20:	db	0
r18:	db	0
r21:	dw	0
;
; ********* End Calculator *********
;

quit:	; Turn off calculator

	ld	a,0dh
	call	CharOut		; Print carriage return to indicate
				; Return to normal
	call	TrigOn		; Enable trigger key checking,
				;  now that calculator no longer active.
;				; "On" flag tells TrigOn to enable checking 
	ld	a,(on)
	cpl	
	ld	(on),a		; Flip calc. running flag to off
;
	pop	hl	; Restore registers 
   	pop	de
	pop	bc
	pop	af
	pop	iy
	pop	ix
;
	ld	sp,(SavStk)	; Restore stack pointer
;
	jp	OrigIn		; = Call BIOS ConIn, ret to transient program 
;
;
TrigOff:	; DISABLE trigger key detection 

	ld	a,(IsOn)	; Is key detection off?
	cp	0
	jp	z,TrigOn	; Yes, turn on
	ld	a,0		; No, flip flag and turn it off
	ld	(IsOn),a
	ld	hl,(JConIn)	; Get place in BIOS to restore jump 
	ld	de,(ConIn)	; Get location of BIOS routine 
	ld	(hl),e
	inc	hl
	ld	(hl),d		; Put in a jp and the location
;
	ld	a,(on)		; Is calculator running?
	or	a
	ret	nz 		; Yes, just resume key detection,
				;  don't tell user 
	ld	de,OffMsg	; Tell user trigger key de-activated
	call	string
	ret

string:	ld	c,9
	jp	BDOS
OnMsg:
	db	'Trigger Key Enabled - Disable Before Re-loading RCP.$'
OffMsg:
	db	'Trigger Key Disabled.$'
RCP$name:
	db	'CALC-RCP ',(vers/10)+'0'
	db	'.0',13,10	;
	db	'H',13,10
	db	'CALC      - Enable/Disable Trigger Key',13,10
	db	'Control-] - Calculator On/Off.$'
OrigOut:
	db	0c3h	; Jp	
con:	dw	0	; Store BIOS console out routine address
;
IsOn:	db	0	; Trigger-key detection on flag
;
OrigIn:
	db	0c3h	; jp
ConIn:	dw	0	; Store BIOS console in routine address  
JConIn:	dw	0	; Store BIOS jump to console in address
;
on:	db	0	; Calculator running flag
;
SavStk:	ds	2	; Save incoming stack pointer
;
	ds	32
NewStk	equ	$	; Our own stack
	
;
; Size error test
;
	if	($ gt (RCP+RCPs*128-1))
SizErr	equ	novalue		; RCP is too large for buffer
	endif
;
	end

	
;
; Size error test
;
	if	($ gt (RCP+RCPs*128-1))
SizErr	equ	noval