From d11e0d2d91ecd05d692b099fbd7352650726f9a8 Mon Sep 17 00:00:00 2001
From: Richard Russell <richard@rtrussell.co.uk>
Date: Tue, 4 Jun 2024 13:41:35 +0100
Subject: [PATCH] v5beta4: Array Arithmetic improved compatibility

---
 WHATSNEW.TXT         |   7 ++-
 bin/cpm/BBCBASIC.COM | Bin 18944 -> 18944 bytes
 src/EVAL.Z80         | 102 +++++++++++++++++++++----------------------
 src/MAIN.Z80         |   2 +-
 4 files changed, 57 insertions(+), 54 deletions(-)

diff --git a/WHATSNEW.TXT b/WHATSNEW.TXT
index a2cf451..2f96ea4 100644
--- a/WHATSNEW.TXT
+++ b/WHATSNEW.TXT
@@ -1,4 +1,4 @@
-New features in BBC BASIC (Z80) version 5.00, May 2024:
+New features in BBC BASIC (Z80) version 5.00, June 2024:
 
 1. BASIC V statements
 
@@ -38,7 +38,10 @@ New features in BBC BASIC (Z80) version 5.00, May 2024:
 3.8  Make a whole array LOCAL
 3.9  DIM a LOCAL array (on the stack) + 
 
-* String array expressions A$() = B$() + C$() are not currently supported.
+* String array expressions are not currently supported, instead of using
+     a$() = b$() + c$()  use  a$() = b$() : a$() += c$()
+  The use of EVAL with whole-array expressions is not currently supported.
+
 + LOCAL string arrays should be initialised to their maximum needed length
   to eliminate the risk of a memory leak each time the PROC/FN is called:
      LOCAL a$() : DIM a$(size%) : a$() = STRING$(max%, "a") : a$() = ""
diff --git a/bin/cpm/BBCBASIC.COM b/bin/cpm/BBCBASIC.COM
index 3541e8bc89aee66760f2d742bb8a027d62ecf45f..228e967416caf3c0f916eb99521836f2e332e66b 100644
GIT binary patch
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diff --git a/src/EVAL.Z80 b/src/EVAL.Z80
index 28b63d5..d3eaf2f 100644
--- a/src/EVAL.Z80
+++ b/src/EVAL.Z80
@@ -10,7 +10,7 @@
 ;
 ;VERSION 2.3, 07-05-1984
 ;VERSION 3.0, 08-03-1987
-;VERSION 5.0, 14-05-2024
+;VERSION 5.0, 31-05-2024
 ;
 ;BINARY FLOATING POINT REPRESENTATION:
 ; 32 BIT SIGN-MAGNITUDE NORMALIZED MANTISSA
@@ -367,6 +367,11 @@ EXPR4B:	CALL	SAVE
 	CALL	DOIT
 	JR	EXPR4A
 ;
+EXPR45:	LD	A,E
+	CP	'+'
+	JR	Z,EXPR4
+	CP	'-'
+	JR	Z,EXPR4
 EXPR5:	CALL	ITEM
 	OR	A		;TEST TYPE
 	EX	AF,AF'		;SAVE TYPE
@@ -395,6 +400,9 @@ EXPRS:	CALL	EXPR
 	RET	M
 	JR	MISMAT
 ;
+BADHEX:	LD	A,28
+ERROR2:	JP	ERROR		;"Bad HEX or binary"
+;
 NEGATE:	EXX
 	LD	A,H
 	CPL
@@ -419,9 +427,6 @@ ADD1:	EXX
 	INC	HL
 	RET
 ;
-BADHEX:	LD	A,28
-ERROR2:	JP	ERROR		;"Bad HEX or binary"
-;
 ITEMI:	CALL	ITEM
 	OR	A
 	JP	P,SFIX
@@ -1914,20 +1919,6 @@ RELOPQ:	CP	'>'
 	CP	'<'
 	RET
 ;
-COMMA:	CALL	NXT
-	INC	IY
-	CP	','
-	RET	Z
-	LD	A,5
-	JR	ERROR1		;"Missing ,"
-;
-BRAKET:	CALL	NXT
-	INC	IY
-	CP	')'
-	RET	Z
-	LD	A,27
-ERROR1:	JP	ERROR		;"Missing )"
-;
 SAVE:	INC	IY
 	AND	0FH
 SAVE1:	EX	AF,AF'
@@ -1966,6 +1957,20 @@ DOIT:	EX	AF,AF'
 	LD	A,(IY)
 	RET
 ;
+COMMA:	CALL	NXT
+	INC	IY
+	CP	','
+	RET	Z
+	LD	A,5
+	JR	ERROR1		;"Missing ,"
+;
+BRAKET:	CALL	NXT
+	INC	IY
+	CP	')'
+	RET	Z
+	LD	A,27
+ERROR1:	JP	ERROR		;"Missing )"
+;
 DISPT2:	PUSH	HL
 	LD	HL,SOPTBL
 	JR	DISPT0
@@ -2044,17 +2049,17 @@ LETARR:	RES	6,D		;Lose array marker
 ; allocate space on stack and zero it:
 ;
 	XOR	A		;Clear carry and zero error code
-	LD	HL,0
+	SBC	HL,HL
 	ADD	HL,SP		;HL = SP
 	SBC	HL,BC
-	JP	C,ERROR		;'No room'
+	JR	C,ERROR1	;'No room'
 	PUSH	BC
 	LD	BC,(FREE)
 	INC	B		;Safety margin
 	SBC	HL,BC
 	ADD	HL,BC
 	POP	BC
-	JP	C,ERROR		;'No room'
+	JR	C,ERROR1	;'No room'
 	LD	SP,HL	
 LETA0:	LD	(HL),0
 	INC	HL
@@ -2094,8 +2099,7 @@ EXPRA1:	INC	IY
 	PUSH	BC
 	PUSH	HL
 	PUSH	IX
-	LD	E,A		;For unary minus
-	CALL	NXT
+	LD	E,A		;Operator
 	CALL	ITEMA
 	POP	IX
 	POP	HL
@@ -2171,16 +2175,20 @@ EXPRA8:	ADD	HL,BC		;Skip remaining elements
 	RET
 ;
 ; ITEMA: evaluate and operate on array item
-;   Inputs: A = operator
-;           D = type
-;           E = operator
+;   Inputs: D = type
+;           E = operator ('=' for first item)
 ;           BC = number of elements
 ;           HL = pointer to destination on stack
 ;           IY = text pointer
 ;  Outputs: IY updated
 ; Destroys: Everything except SP
 ;
-ITEMA:	CP	'-'
+ITEMA:	CALL	NXT
+	PUSH	HL		;Pointer to destination
+	PUSH	BC		;Number of elements
+	PUSH	IY		;In case normal expression
+	PUSH	DE		;Ditto
+	CP	'-'
 	JR	NZ,ITEMA1	;Not unary minus
 	LD	A,E
 	CP	'='
@@ -2188,16 +2196,14 @@ ITEMA:	CP	'-'
 	INC	IY		;Bump past '-'
 	CALL	NXT
 	LD	E,'-'		;Unary minus
-ITEMA1:	PUSH	HL		;Pointer to destination
-	PUSH	BC		;Number of elements
-	PUSH	DE		;Type and previous operator
-	PUSH	IY		;In case normal expression
+ITEMA1:	PUSH	DE		;Type and operator
 	CALL	GETVAR
+	POP	DE		;Type & operator
 	JR	NZ,ITEMA4	;Non-array expression
 	BIT	6,A
 	JR	Z,ITEMA4	;Not a whole array
+	POP	BC		;Junk saved original op
 	POP	BC		;Junk saved text pointer
-	POP	DE		;Type & operator
 	RES	6,A
 	CP	D
 	JP	NZ,MISMAT	;'Type mismatch'
@@ -2258,10 +2264,12 @@ ITEMA3:	EX	DE,HL		;DE = destination
 ;
 ; Process numeric non-array item:
 ;
-ITEMA4:	POP	IY		;Restore text pointer
+ITEMA4:	POP	DE		;Restore original operator
+	POP	IY		;Restore original text pointer
 	BIT	7,D
 	JR	NZ,ITEMA5
-	CALL	EXPR4		;; should be EXP345
+	PUSH	DE
+	CALL	EXPR45		;; should be EXP345
 	LD	A,C		;Exponent
 	POP	DE		;Type / operator
 	POP	BC		;Count
@@ -2302,8 +2310,7 @@ ITEMA5:	CALL	EXPRS
 	LD	C,A
 	LD	B,0
 	LDIR
-ITEMA0:	POP	DE
-	POP	BC
+ITEMA0:	POP	BC
 	POP	IX
 	EXX
 	LD	L,A
@@ -2361,13 +2368,11 @@ ARRDOT:	INC	IY		;Bump past dot
 	JR	Z,ARR1D
 	LD	H,(IY-1)
 	LD	L,(IY-2)
-ARR1D:	PUSH	AF
-	PUSH	DE
-	LD	C,A
-	LD	B,0
-	CALL	MUL16
+ARR1D:	PUSH	DE
+	EX	DE,HL
+	CALL	X14OR5
+	EX	DE,HL
 	POP	DE
-	POP	AF
 	LD	B,(IX-1)
 	LD	C,(IX-2)
 ;
@@ -2518,9 +2523,7 @@ INNER:	PUSH	DE		;6
 	ADD	IY,BC
 	PUSH	AF
 	PUSH	HL
-	EX	DE,HL
-	CALL	MUL16
-	EX	DE,HL
+	CALL	X14OR5
 	POP	BC
 	CALL	MOD16
 	POP	AF
@@ -2540,12 +2543,9 @@ INNER:	PUSH	DE		;6
 	SBC	HL,DE
 	PUSH	HL
 	POP	IY
-	LD	L,A
-	LD	H,0
-	PUSH	AF
-	CALL	MUL16
-	POP	AF
-	EX	DE,HL
+	LD	D,B
+	LD	E,C
+	CALL	X14OR5
 	ADD	IX,DE
 	POP	HL
 	POP	DE
diff --git a/src/MAIN.Z80 b/src/MAIN.Z80
index 341655f..1753333 100644
--- a/src/MAIN.Z80
+++ b/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 5beta3'
+VERMSG:	DEFM	'BBC BASIC (Z80) Version 5beta4'
 	DEFB	CR
 	DEFB	LF
 NOTICE:	DEFM	'(C) Copyright R.T.Russell 2024'