v5beta6: Added Acorn Z80 edition

README.md

@@ -10,8 +10,8 @@ More details of the features added in version 5.00 can be found in the file WHAT
 
 The files in green constitute the generic BBC BASIC interpreter which is shared by all the
 editions, it (just!) fits in 16 Kbytes so could be held in a ROM of this size.  The files in
-the blue box are used to build the CP/M edition.  The files in the red box are used to build
+the blue box are used to build the generic CP/M edition.  The files in the red box are used
-the Acorn Z80 Second Processor edition (in principle: the source files are on an 8" floppy!)
+to build the Acorn Z80 Second Processor edition.
 
 Note that the name 'BBC BASIC' is used by permission of the British Broadcasting Corporation
 and is not transferrable to a derived or forked work.

WHATSNEW.TXT

@@ -50,17 +50,18 @@ New features in BBC BASIC (Z80) version 5.00, June 2024:
 
 4.1  Bit-shifts <<, >>, >>>
 4.2  Floating-point indirection (|)
-4.3  RETURNed parameters from FN/PROC
+4.3  Additional VDU delimiter '|' 
-4.4  Compound assignment (+=, -=, *=, /= etc.)
+4.4  RETURNed parameters from FN/PROC
-4.5  Assigning to a sub-string: LEFT$()=, MID$()= , RIGHT$()=
+4.5  Compound assignment (+=, -=, *=, /= etc.)
-4.6  Hooks for CIRCLE,ELLIPSE,FILL,LINE,MOUSE,ORIGIN,RECTANGLE,TINT,SYS,WAIT
+4.6  Assigning to a sub-string: LEFT$()=, MID$()= , RIGHT$()=
-4.7  Hooks for WIDTH function, TINT function, MODE function
+4.7  Hooks for CIRCLE,ELLIPSE,FILL,LINE,MOUSE,ORIGIN,RECTANGLE,SYS,TINT,WAIT
+4.8  Hooks for MODE function, TINT function, WIDTH function
 
 5. Extensions to Acorn's BASIC V, compatible with BB4W, BBCSDL and BBCTTY
 
 5.1  EXIT REPEAT / WHILE / FOR [var]
 5.2  Address-of operator (^)
-5.3  Byte variables and arrays (& suffix)
+5.3  Byte (unsigned 8-bit) variables and arrays (& suffix)
 5.4  'BY len' and 'TO term' qualifiers to GET$#file
 5.5  ELSE IF <condition> THEN; (trailing semicolon)
 5.6  == synonymous with = in comparisons

bin/acorn/MAKE.SUB

@@ -0,0 +1,13 @@
+z80asm main/rmf
+z80asm exec/rmf
+z80asm eval/rmf
+z80asm asmb/rmf
+z80asm math/rmf
+z80asm amos/rmf
+z80asm acorn/rmf
+z80asm data/rmf
+era bbctube.com
+link bbctube=/p:0100,main,exec,eval,asmb,math,acorn,amos,/p:4B00,data
+hexbin bbctube
+era bbctube.hex
+ren bbctube.com=bbctube.bin

src/ACORN.Z80

@@ -0,0 +1,737 @@
+	TITLE	COPYRIGHT (C) R.T.RUSSELL 1983-2024
+;
+;PATCH FOR BBC BASIC TO CP/M 2.2 & 3.0
+;* ACORN COMPUTERS Z80 TUBE VERSION  *
+;(C) COPYRIGHT R.T.RUSSELL, 02-01-1984
+;VERSION 5.0, 16-06-2024
+;
+OSWRCH	EQU	0FFEEH
+OSWORD	EQU	0FFF1H
+OSBYTE	EQU	0FFF4H
+;
+ESC	EQU	1BH
+TBY	EQU	0FH
+TTO	EQU	0B8H
+TFILL	EQU	03H
+;
+	EXTRN	ITEMI
+	EXTRN	EXPRI
+	EXTRN	COMMA
+	EXTRN	TERMQ
+	EXTRN	BRAKET
+	EXTRN	EXTERR
+	EXTRN	STOREN
+	EXTRN	TRAP
+	EXTRN	VAR
+	EXTRN	NXT
+	EXTRN	XEQ
+;
+	EXTRN	ACCS
+	EXTRN	COUNT
+	EXTRN	WIDTH
+	EXTRN	SCRAP
+;
+	GLOBAL	OSCALL
+	GLOBAL	CLRSCN
+	GLOBAL	PUTCSR
+	GLOBAL	GETCSR
+	GLOBAL	PUTIME
+	GLOBAL	GETIME
+	GLOBAL	OSKEY
+;
+	GLOBAL	CLG
+	GLOBAL	MOVE
+	GLOBAL	DRAW
+	GLOBAL	PLOT
+	GLOBAL	MODE
+	GLOBAL	COLOUR
+	GLOBAL	GCOL
+	GLOBAL	ADVAL
+	GLOBAL	SOUND
+	GLOBAL	ENVEL
+	GLOBAL	POINT
+;
+	GLOBAL	CIRCLE
+	GLOBAL	ELLIPS
+	GLOBAL	FILL
+	GLOBAL	MOUSE
+	GLOBAL	ORIGIN
+	GLOBAL	RECTAN
+	GLOBAL	LINE
+	GLOBAL	TINT
+	GLOBAL	WAIT
+	GLOBAL	SYS
+;
+	GLOBAL	PUTIMS
+	GLOBAL	GETIMS
+	GLOBAL	TINTFN
+	GLOBAL	MODEFN
+	GLOBAL	WIDFN
+;
+;GETIME	- Read elapsed-time clock.
+;  	  Outputs:  DEHL = elapsed time (centiseconds)
+; 	  Destroys: A,D,E,H,L,F
+;
+GETIME:	LD	A,1
+	LD	HL,SCRAP
+	CALL	OSWORD
+	LD	HL,SCRAP
+	LD	E,(HL)
+	INC	HL
+	LD	D,(HL)
+	INC	HL
+	LD	A,(HL)
+	INC	HL
+	LD	H,(HL)
+	LD	L,A
+	EX	DE,HL
+	RET
+;
+;GETIMS	- Read real-time clock as string.
+;  	  Outputs:  TIME$ in string accumulator
+;                   E = string length (25)
+; 	  Destroys: A,B,C,D,E,H,L,F
+;
+GETIMS:	LD	A,14
+	LD	HL,SCRAP
+	LD	(HL),0
+	CALL	OSWORD
+	LD	HL,SCRAP
+	LD	DE,ACCS
+	LD	A,(HL)
+	CP	E
+	RET	Z
+	LD	BC,25
+	LDIR
+	RET
+;
+;
+;PUTIME	- Load elapsed-time clock.
+;   	  Inputs:   DEHL = time to load (centiseconds)
+; 	  Destroys: A,D,E,H,L,F
+;
+PUTIME:	PUSH	IX
+	LD	IX,SCRAP
+	LD	(IX+0),L
+	LD	(IX+1),H
+	LD	(IX+2),E
+	LD	(IX+3),D
+	LD	A,2
+	LD	HL,SCRAP
+	CALL	OSWORD
+	POP	IX
+	RET
+;
+;PUTIMS	- Wtite real-time clock as string.
+;  	  Inputs:   string in string accumulator
+;                   E = string length
+; 	  Destroys: A,B,C,D,E,H,L,F
+;
+PUTIMS:	LD	A,E		;Length
+	CP	26
+	RET	NC
+	LD	B,0
+	LD	C,A
+	LD	DE,SCRAP+1
+	LD	HL,ACCS
+	LDIR
+	LD	HL,SCRAP
+	LD	(HL),A
+	LD	A,15
+	JP	OSWORD
+;
+;
+;CLRSCN	- Clear screen.
+; 	  Destroys: A,D,E,H,L,F
+;
+CLRSCN:	LD	A,0CH
+	JP	OSWRCH
+;
+;
+;OSKEY	- Sample keyboard with specified wait.
+;   	  Inputs:   HL = Time to wait (centiseconds)
+;  	  Outputs:  Carry reset indicates time-out.
+;                   If carry set, A = character typed.
+; 	  Destroys: A,D,E,H,L,F
+;
+OSKEY:	LD	A,129
+	CALL	OSBYTE
+	LD	A,H
+	OR	A
+	RET	NZ		;TIME-OUT, CARRY RESET
+	LD	A,L
+	SCF
+	RET			;NORMAL, CARRY SET
+;
+;PUTCSR	- Move cursor to specified position.
+;   	  Inputs:   DE = horizontal position (LHS=0)
+;                   HL = vertical position (TOP=0)
+; 	  Destroys: A,D,E,H,L,F
+;
+PUTCSR:	LD	A,1FH
+	CALL	OSWRCH
+	LD	A,E
+	CALL	OSWRCH
+	LD	A,L
+	JP	OSWRCH
+;
+;GETCSR	- Return cursor coordinates.
+;   	  Outputs:  DE = X coordinate (POS)
+;                   HL = Y coordinate (VPOS)
+;  	  Destroys: A,D,E,H,L,F
+;
+GETCSR:	LD	A,134
+	CALL	OSBYTE
+	LD	E,L
+	LD	L,H
+	LD	D,0
+	LD	H,D
+	RET
+;
+;POINT - var=POINT(x,y)
+;
+POINT:	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	DE
+	CALL	BRAKET
+	LD	IX,SCRAP
+	LD	(IX+0),E
+	LD	(IX+1),D
+	LD	(IX+2),L
+	LD	(IX+3),H
+	LD	HL,SCRAP
+	LD	A,9
+	CALL	OSWORD
+	LD	A,(IX+4)
+	LD	L,A
+	ADD	A,1
+	SBC	A,A
+	LD	H,A
+RETEXX:	EXX
+	LD	H,A
+	LD	L,A
+	XOR	A
+	LD	C,A
+	RET
+;
+;ADVAL - var=ADVAL(n)
+;
+ADVAL:	CALL	ITEMI
+	EXX
+	LD	A,128
+	CALL	OSBYTE
+	XOR	A
+	JR	RETEXX
+;
+;MODEFN - var=MODE
+;
+MODEFN:	LD	A,135
+	CALL	OSBYTE
+	LD	L,H
+RETU8:	XOR	A
+	LD	H,A
+	JR	RETEXX
+;
+;WIDFN - var=WIDTH
+;
+WIDFN:	LD	A,(WIDTH)
+	LD	L,A
+	JR	RETU8
+;
+;ENVEL - ENVELOPE var,var,var,var,var,var,var,
+;                 var,var,var,var,var,var,var
+;
+ENVEL:	LD	B,0
+	LD	IX,SCRAP
+	PUSH	BC
+	PUSH	IX
+ENVEL1:	CALL	EXPRI
+	EXX
+	POP	IX
+	POP	BC
+	LD	(IX),L
+	LD	A,B
+	CP	13
+	JR	Z,ENVEL2
+	INC	B
+	INC	IX
+	PUSH	BC
+	PUSH	IX
+	CALL	COMMA
+	JR	ENVEL1
+ENVEL2:	LD	HL,SCRAP
+	LD	A,8
+	CALL	OSWORD
+	JP	XEQ
+;
+;SOUND - SOUND var,var,var,var
+;
+SOUND:	LD	B,0
+	LD	IX,SCRAP
+	PUSH	BC
+	PUSH	IX
+SOUND1:	CALL	EXPRI
+	EXX
+	POP	IX
+	POP	BC
+	LD	(IX+0),L
+	LD	(IX+1),H
+	INC	IX
+	INC	IX
+	INC	B
+	INC	B
+	LD	A,B
+	CP	8
+	JR	Z,SOUND2
+	PUSH	BC
+	PUSH	IX
+	CALL	COMMA
+	JR	SOUND1
+SOUND2:	LD	HL,SCRAP
+	LD	A,7
+	CALL	OSWORD
+	JP	XEQ
+;
+;MODE - MODE n
+;
+MODE:	CALL	EXPRI
+	XOR	A
+	LD	(COUNT),A
+	EXX
+	LD	H,L
+	LD	L,22
+	CALL	WRCH2
+	JR	XEQGO1
+;
+;CLG
+;
+CLG:	LD	A,16
+	CALL	OSWRCH
+	JR	XEQGO1
+;
+;ORIGIN x,y
+;
+ORIGIN: CALL    EXPRI
+        EXX
+	PUSH	HL
+        CALL    CEXPRI
+	EXX
+        POP	DE
+	LD	C,29
+	CALL	WRCH5
+        JR	XEQGO1
+;
+;COLOUR n
+;COLOUR n,p
+;COLOUR n,r,g,b
+;
+COLOUR:	CALL	EXPRI		;n
+	EXX
+	LD	A,(IY)
+	CP	','
+        JR      Z,PALCOL
+	LD	H,L
+	LD	L,17
+	CALL	WRCH2
+	JR	XEQGO1
+;
+PALCOL:	PUSH	HL
+	CALL	CEXPRI		;p or r
+	EXX
+	EX	DE,HL
+	LD	HL,0
+	LD	A,(IY)
+	CP	','
+	JR	NZ,PALET1
+	PUSH	DE
+	CALL	CEXPRI		;g
+	EXX
+	PUSH	HL
+	CALL	CEXPRI		;b
+	EXX
+	POP	DE
+	POP	BC
+	LD	A,L
+	POP	HL
+	LD	D,C		;r
+	LD	C,L		;n
+	LD	L,E		;g
+	LD	H,A		;b
+	LD	E,16
+	PUSH	BC
+PALET1:	POP	BC
+	LD	B,19
+	CALL	WRCH6
+	JR	XEQGO1
+;
+;GCOL [a,]b
+;
+GCOL:	CALL	EXPRI
+	EXX
+	LD	E,0
+	LD	A,(IY)
+	CP	','
+	JR	NZ,GCOL0
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	DE
+GCOL0:	LD	H,L
+	LD	L,E
+	LD	D,18
+	CALL	WRCH3		;DLH
+XEQGO1:	JP	XEQ
+;
+;LINE x1,y1,x2,y2
+;
+LINE:	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	EXPR3
+	EX	(SP),HL		;HL <- x1, (SP) <- y2
+	PUSH	BC
+	EX	DE,HL
+	LD	C,4
+	CALL	VDU25
+	POP	DE
+	POP	HL
+	LD	C,5
+	JR	PLOT4A
+;
+;CIRCLE [FILL] x,y,r
+;
+CIRCLE:	CP	TFILL
+	PUSH	AF
+	JR	NZ,CIRCL0
+	INC	IY
+CIRCL0:	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	BC		;y
+	POP	DE		;x
+	PUSH	HL
+	LD	L,C
+	LD	H,B
+	LD	C,4		; PLOT 4 = MOVE
+	CALL	VDU25
+	POP	DE		;r
+	LD	HL,0
+        POP	AF
+	LD	C,145		; PLOT 145 = outline circle
+	JR	NZ,PLOT4A
+	LD	C,153		; PLOT 153 = filled circle
+PLOT4A:	JR	PLOT4
+;
+;ELLIPSE [FILL] x,y,a,b
+;
+ELLIPS:	CP	TFILL
+	PUSH	AF
+	JR	NZ,ELLIP0
+	INC	IY
+ELLIP0:	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	EXPR3
+	EX	(SP),HL		;HL <- x, (SP) <- b
+	PUSH	BC
+	EX	DE,HL
+	LD	C,4		; PLOT 4 = Move absolute
+	CALL	VDU25
+	POP	DE		;a
+	PUSH	DE
+	LD	HL,0
+	LD	C,L		; PLOT 0 - Move relative
+	CALL	VDU25
+        POP	DE		;a
+	XOR	A
+	LD	L,A
+	LD	H,A
+	SBC	HL,DE
+	EX	DE,HL
+	POP	HL		;b
+	POP	AF
+	LD	C,193		; PLOT 193 = outline ellipse
+	JR	NZ,PLOT4
+	LD	C,201		; PLOT 201 = filled ellipse
+	JR	PLOT4
+;
+;MOVE [BY} x,y
+;DRAW [BY] x,y
+;PLOT [BY] [n,]x,y
+;FILL [BY] x,y
+;
+MOVE:	LD	C,4
+	JR	PLOT1
+;
+DRAW:	LD	C,5
+	JR	PLOT1
+;
+FILL:	LD	C,133
+	JR	PLOT1
+;
+PLOT:	LD	C,69
+	CP	TBY
+	JR	Z,PLOT1
+	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	LD	A,(IY)
+	CP	','
+	JR	Z,PLOT3
+	POP	DE
+	LD	C,69
+	JR	PLOT4
+;
+PLOT1:	CP	TBY
+	JR	NZ,PLOT2
+	INC	IY
+	RES	2,C		;Change absolute to relative
+PLOT2:	PUSH	BC
+	CALL	EXPRI
+	EXX
+PLOT3:	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	DE
+	POP	BC
+PLOT4:	CALL	VDU25
+	JP	XEQ
+;
+;RECTANGLE [FILL] x,y,w[,h] [TO xnew,ynew]
+;
+RECTAN:	CP	TFILL
+	PUSH	AF
+	JR	NZ,RECT0
+	INC	IY
+RECT0:	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	PUSH	HL
+	LD	A,(IY)
+	CP	','
+	JR	NZ,RECT1
+	CALL	CEXPRI
+	EXX
+RECT1:	POP	BC		;w
+	POP	DE		;y
+	EX	(SP),HL		;HL <- x, (SP) <- h
+	PUSH	BC
+	EX	DE,HL
+	LD	C,4
+	CALL	VDU25
+	LD	A,(IY)
+	CP	TTO
+	JR	Z,RECTTO
+	POP	DE		;w
+	POP	HL		;h
+	POP	AF
+	JR	NZ,OUTLIN
+	LD	C,97
+	JR	PLOT4
+;
+;Block copy / move:
+;
+RECTTO:	INC	IY		; Bump over TO
+	CALL	EXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	BC		;newx
+	POP	DE		;w
+	EX	(SP),HL		;HL <- h, (SP) <- newy
+	PUSH	BC
+	EX	DE,HL
+	LD	C,0
+	CALL	VDU25
+	POP	DE		;newx
+	POP	HL		;newy
+	POP	AF
+	LD	C,190		; PLOT 190 - Block copy
+	JR	NZ,PLOT4B
+	DEC	C		; PLOT 189 - Block move
+PLOT4B:	JR	PLOT4
+;
+;Outline rectangle:
+;
+OUTLIN:	LD	C,9		; PLOT 9 - draw relative
+	PUSH	HL
+	LD	HL,0
+	CALL	VDU25		; side 1
+	POP	HL
+	PUSH	DE
+	LD	DE,0
+	CALL	VDU25		; side 2
+	POP	DE
+	PUSH	HL
+	XOR	A
+	LD	L,A
+	LD	H,A
+	SBC	HL,DE
+	EX	DE,HL
+	LD	L,A
+	LD	H,A
+	CALL 	VDU25		; side 3
+	POP	DE
+	XOR	A
+	LD	L,A
+	LD	H,A
+	SBC	HL,DE
+	LD	E,A
+	LD	D,A
+	JR	PLOT4B
+;
+;MOUSE x, y, b
+;
+MOUSE:	LD	A,128
+	LD	HL,9
+	CALL	OSBYTE
+	PUSH	HL
+	LD	A,128
+	LD	HL,8
+	CALL	OSBYTE
+	PUSH	HL
+	LD	A,128
+	LD	HL,7
+	CALL	OSBYTE
+	PUSH	HL
+	CALL	VAR
+	POP	HL
+	CALL	STOREI
+	CALL	COMMA
+	CALL	NXT
+	CALL	VAR
+	POP	HL
+	CALL	STOREI
+	CALL	COMMA
+	CALL	NXT
+	CALL	VAR
+	POP	HL
+	CALL	STOREI
+XEQGO2:	JP	XEQ
+;
+;WAIT [n]
+;
+WAIT:	CALL	TERMQ
+	JR	Z,XEQGO2
+	CALL	EXPRI
+	EXX
+	LD	B,H
+	LD	C,L
+	CALL	GETIME
+	ADD	HL,BC
+	LD	BC,0
+	EX	DE,HL
+	ADC	HL,BC
+	EX	DE,HL
+WAIT1:	CALL	TRAP
+	PUSH	DE
+	PUSH	HL
+	CALL	GETIME
+	POP	BC
+	OR	A
+	SBC	HL,BC
+	LD	H,B
+	LD	L,C
+	EX	DE,HL
+	POP	BC
+	SBC	HL,BC
+	JR	NC,XEQGO2
+	EX	DE,HL
+	LD	D,B
+	LD	E,C
+	JR	WAIT1
+;
+;OSCALL - Trap call to FFxx
+;
+OSCALL:	POP	HL		;DITCH RETURN ADDRESS
+	LD	HL,OSRET
+	PUSH	HL		;NEW RETURN ADDRESS
+	LD	A,(IX+4)	;A%
+	LD	E,(IX+20)	;E%
+	LD	H,(IX+100)	;Y%
+	LD	L,(IX+96)	;X%
+	JP	(IY)
+OSRET:	PUSH	AF
+	LD	A,L		;F  H  L  A
+	LD	L,H		;|  |  |  |
+	EXX			;|  |  |  |
+	POP	BC		;|  |  |  |
+	LD	H,A		;|  |  |  |
+	LD	L,B		;H  L  H' L'
+	LD	A,C
+	EXX
+	LD	H,A
+	RET
+;
+VDU25:	LD	B,25
+WRCH6:	LD	A,B
+	CALL	OSWRCH
+WRCH5:	LD	A,C
+	CALL	OSWRCH
+WRCH4:	LD	A,E
+	CALL	OSWRCH
+WRCH3:	LD	A,D
+	CALL	OSWRCH
+WRCH2:	LD	A,L
+	CALL	OSWRCH
+	LD	A,H
+	JP	OSWRCH
+;
+EXPR3:	CALL	CEXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	PUSH	HL
+	CALL	CEXPRI
+	EXX
+	POP	BC		;x2
+	POP	DE		;y1
+	RET
+;
+CEXPRI:	CALL	COMMA
+	JP	EXPRI
+;
+STOREI:	BIT	7,A
+	JR	NZ,EEK
+	BIT	6,A
+	JR	NZ,EEK
+	EXX
+	LD	HL,0
+	LD	C,L
+	JP	STOREN
+;
+EEK:	LD	A,50
+	CALL	EXTERR
+	DEFB	13H		;'Bad '
+	DEFB	04H		;'MOUSE'
+	DEFB	20H
+	DEFB	15H		;'variable'
+	DEFB	0
+;
+TINT:
+TINTFN:
+SYS:
+	XOR	A
+	CALL	EXTERR
+	DEFM	'Sorry'
+	DEFB	0
+;
+	END
+                                                          

src/CMOS.Z80

@@ -440,14 +440,14 @@ INCRDF:	CALL	INCSEC
 ;
 READ:	CALL	SETDMA
 	LD	A,33
-BDOS1:	CALL	BDOS0		;*
+BDOS1:	CALL	BDOS0
-	JR	NZ,CPMERR	;*
+	JR	NZ,CPMERR
-	OR	A		;*
+	OR	A
-	RET			;*
+	RET
-CPMERR:	LD	A,255		;* CP/M 3
+CPMERR:	LD	A,255
-	CALL	EXTERR		;* BDOS ERROR
+	CALL	EXTERR
-	DEFM	'CP/M Error'	;*
+	DEFM	'CP/M Error'
-	DEFB	0		;*
+	DEFB	0
 ;
 BDOS0:	PUSH	BC
 	PUSH	DE
@@ -456,8 +456,8 @@ BDOS0:	PUSH	BC
 	PUSH	IY
 	LD	C,A
 	CALL	BDOS
-	INC	H		;* TEST H
+	INC	H
-	DEC	H		;* CP/M 3 ONLY
+	DEC	H
 	POP	IY
 	POP	IX
 	POP	HL
@@ -883,10 +883,10 @@ DIR1:	CALL	LTRAP
 	LD	HL,DSKBUF+1
 	ADD	HL,DE
 	PUSH	HL
-	LD	DE,8		;**
+	LD	DE,8
 	ADD	HL,DE
-	LD	E,(HL)		;**
+	LD	E,(HL)
-	INC	HL		;**
+	INC	HL
 	BIT	7,(HL)		;SYSTEM FILE?
 	POP	HL
 	LD	C,18
@@ -899,13 +899,13 @@ DIR1:	CALL	LTRAP
 	ADD	A,'A'
 	CALL	OSWRCH
 	LD	B,8
-	LD	A,' '		;**
+	LD	A,' '
-	BIT	7,E		;** READ ONLY?
+	BIT	7,E		;READ ONLY?
-	JR	Z,DIR3		;**
+	JR	Z,DIR3
-	LD	A,'*'		;**
+	LD	A,'*'
 DIR3:	CALL	CPTEXT
 	LD	B,3
-	LD	A,' '		;**
+	LD	A,' '
 	CALL	SPTEXT
 	POP	BC
 	DJNZ	DIR2
@@ -1046,11 +1046,11 @@ COMDS:	DEFM	'BY'
 ;            B = number of characters to print
 ; Destroys: A,B,H,L,F
 ;
-CPTEXT:	PUSH	AF		;**
+CPTEXT:	PUSH	AF
 	LD	A,':'
 	CALL	OSWRCH
-	POP	AF		;**
+	POP	AF
-SPTEXT:	CALL	OSWRCH		;**
+SPTEXT:	CALL	OSWRCH
 PTEXT:	LD	A,(HL)
 	AND	7FH
 	INC	HL

src/EXEC.Z80

@@ -10,7 +10,7 @@
 ;
 ;VERSION 2.1, 22-01-1984
 ;VERSION 3.1, 11-06-1987
-;VERSION 5.0, 10-06-2024
+;VERSION 5.0, 16-06-2024
 ;
 	GLOBAL	XEQ
 	GLOBAL	RUN0
@@ -1557,14 +1557,14 @@ IF:	CALL	EXPRI
 	JR	Z,IFNOT		;FALSE
 	LD	A,(IY)
 	CP	TTHEN
-	JR	NZ,XEQGO7
+	JP	NZ,XEQ
 IF0:	INC	IY		;SKIP "THEN"
 	LD	A,(IY)
 	CP	';'
 	JR	Z,IF0
 IF1:	CALL	NXT
 	CP	TLINO
-	JR	NZ,XEQGO7	;STATEMENT FOLLOWS
+	JP	NZ,XEQ		;STATEMENT FOLLOWS
 	JP	GOTO		;LINE NO. FOLLOWS
 ;
 IFELSE:	LD	A,(IY)
@@ -1968,13 +1968,17 @@ TRACE0:	DEC	HL
 TRACE1:	LD	(TRACEN),HL
 	JR	XEQGO1
 ;
-;VDU expr,expr;....
+;VDU expr,expr;....[|]
 ;
 VDU:	CALL	EXPRI
 	EXX
 	LD	A,L
-	CALL	OSWRCH
+	LD	B,1
+VDU1:	CALL	OSWRCH
+	DJNZ	VDU1
 	LD	A,(IY)
+	CP	'|'
+	JR	Z,VDU4
 	CP	','
 	JR	Z,VDU2
 	CP	';'
@@ -1986,6 +1990,11 @@ VDU3:	CALL	TERMQ
 	JR	NZ,VDU
 	JR	XEQGO1
 ;
+VDU4:	INC	IY
+	XOR	A
+	LD	B,9
+	JR	VDU1
+;
 ;CLOSE channel number
 ;
 CLOSE:	CALL	CHANEL

src/MAIN.Z80

@@ -174,7 +174,7 @@ PURGE:	LD	(HL),A		;CLEAR SCRATCHPAD
 	CALL	NEWIT
 	JP	NZ,CHAIN0	;AUTO-RUN
 	CALL	TELL
-VERMSG:	DEFM	'BBC BASIC (Z80) Version 5beta5'
+VERMSG:	DEFM	'BBC BASIC (Z80) Version 5beta6'
 	DEFB	CR
 	DEFB	LF
 NOTICE:	DEFM	'(C) Copyright R.T.Russell 2024'

src/MATH.Z80

@@ -4,7 +4,7 @@
 ;(C) COPYRIGHT  R.T.RUSSELL  1986-2024
 ;VERSION 0.0, 26-10-1986
 ;VERSION 0.1, 14-12-1988 (BUG FIX)
-;VERSION 5.0, 21-05-2024 (SHIFTS ADDED)
+;VERSION 5.0, 16-06-2024 (SHIFTS ADDED)
 ;
 ;BINARY FLOATING POINT REPRESENTATION:
 ;   32 BIT SIGN-MAGNITUDE NORMALIZED MANTISSA
@@ -387,16 +387,7 @@ IMUL:	LD	A,H
 	JP	NEGATE
 ;
 IMUL1:	DEC	C
-	EXX
+	CALL	SLA8
-	SLA	E
-	RL	D
-	EXX
-	RL	E
-	RL	D
-	EXX
-	ADC	HL,HL
-	EXX
-	ADC	HL,HL
 	JP	P,IMUL1		;NORMALISE
 	EX	AF,AF'
 	RET	M
@@ -2177,30 +2168,12 @@ SQR2:	INC	A
 	RET	P
 SQRA:	SLA	C
 	RL	B
+	INC	C
 	EXX
 	RL	C
 	RL	B
-	EXX
+	CALL	SLA8
-	INC	C
+	CALL	SLA8
-	SLA	E
-	RL	D
-	EXX
-	RL	E
-	RL	D
-	EXX
-	ADC	HL,HL
-	EXX
-	ADC	HL,HL
-	EXX
-	SLA	E
-	RL	D
-	EXX
-	RL	E
-	RL	D
-	EXX
-	ADC	HL,HL
-	EXX
-	ADC	HL,HL
 	EXX
 	JP	NC,SQR1
 SQR3:	OR	A
@@ -2230,6 +2203,18 @@ SQRB:	ADD	HL,HL
 	DEC	C
 	RET
 ;
+SLA8:	EXX
+	SLA	E
+	RL	D
+	EXX
+	RL	E
+	RL	D
+	EXX
+	ADC	HL,HL
+	EXX
+	ADC	HL,HL
+	RET
+;
 DIGITQ:	LD	A,(IX)
 	CP	'9'+1
 	CCF