lib/expr: make EXPR_PARSE put result in DE instead of IX

Finally getting rid of this bad mistake of using IX for this.

apps/basic/var.asm

@@ -98,12 +98,9 @@ parseLiteralOrVar:
 	push	hl	; --> lvl 1
 	ld	hl, VAR_TBL
 	call	addHL
-	push	de	; --> lvl 2
 	ld	e, (hl)
 	inc	hl
 	ld	d, (hl)
-	push	de \ pop ix
-	pop	de	; <-- lvl 2
 	pop	hl	; <-- lvl 1
 	cp	a	; ensure Z
 	ret

apps/lib/expr.asm

@@ -5,7 +5,7 @@
 ;
 ; EXPR_PARSE: routine to call to parse literals or symbols that are part of
 ;             the expression. Routine's signature:
-;	      String in (HL), returns its parsed value to IX. Z for success.
+;	      String in (HL), returns its parsed value to DE. Z for success.
 ;
 ; *** Code ***
 ;
@@ -258,7 +258,6 @@ _parseNumber:
 	ret
 .skip1:
 	; End of special case 1
-	push	ix
 	; Copy beginning of string to DE, we'll need it later
 	ld	d, h
 	ld	e, l
@@ -288,19 +287,16 @@ _parseNumber:
 	xor	a
 	ld	(hl), a
 	ex	de, hl	; rewind to beginning of number
-	call	EXPR_PARSE
+	call	EXPR_PARSE	; --> DE
 	ex	af, af'		; keep result flags away while we restore (HL)
-	push	ix \ pop de	; result in DE
 	pop	hl	; <-- lvl 2, end of string
 	pop	af	; <-- lvl 1, saved op
 	ld	(hl), a
 	ex	af, af'		; restore Z from EXPR_PARSE
-	jr	nz, .end
+	ret	nz
 	; HL is currently at the end of the number's string
 	; On success, have A be the operator char following the number
 	ex	af, af'
-.end:
-	pop	ix
 	ret
 
 ; Sets Z if A contains a valid operator char or a null char.

apps/lib/parse.asm

@@ -67,7 +67,7 @@ parseHexPair:
 ;	add	a, 0xff-'9'	; maps '0'-'9' onto 0xf6-0xff
 ;	sub	0xff-9		; maps to 0-9 and carries if not a digit
 
-; Parse string at (HL) as a decimal value and return value in IX under the
+; Parse string at (HL) as a decimal value and return value in DE under the
 ; same conditions as parseLiteral.
 ; Sets Z on success, unset on error.
 ; To parse successfully, all characters following HL must be digits and those
@@ -76,7 +76,7 @@ parseHexPair:
 ; digit in the string.
 
 parseDecimal:
-	push 	hl
+	push 	hl		; --> lvl 1
 
 	ld	a, (hl)
 	add	a, 0xff-'9'	; maps '0'-'9' onto 0xf6-0xff
@@ -129,23 +129,23 @@ parseDecimal:
 	; to 0x00+(0xff-'9')-(0xff-9)=-0x30=0xd0
 	sub 	0xd0	; if a is null, set Z
 			; a is checked for null before any errors
-	push	hl \ pop ix
-	exx	; restore original de and bc
-	pop	hl
+	push	hl	; --> lvl 2, result
+	exx		; restore original bc
+	pop	de	; <-- lvl 2, result
+	pop	hl	; <-- lvl 1, orig
 	ret	z
 	; A is not 0? Ok, but if it's a space, we're happy too.
 	jp	isWS
 .error:
-	pop	hl
+	pop	hl	; <-- lvl 1, orig
 	jp	unsetZ
 
-; Parse string at (HL) as a hexadecimal value and return value in IX under the
+; Parse string at (HL) as a hexadecimal value and return value in DE under the
 ; same conditions as parseLiteral.
 parseHexadecimal:
 	call	hasHexPrefix
 	ret	nz
 	push	hl
-	push	de
 	ld	d, 0
 	inc	hl	; get rid of "0x"
 	inc	hl
@@ -179,8 +179,6 @@ parseHexadecimal:
 .error:
 	call	unsetZ
 .end:
-	push	de \ pop ix
-	pop	de
 	pop	hl
 	ret
 
@@ -196,15 +194,14 @@ hasHexPrefix:
 	pop	hl
 	ret
 
-; Parse string at (HL) as a binary value (0b010101) and return value in IX.
-; High IX byte is always clear.
+; Parse string at (HL) as a binary value (0b010101) and return value in E.
+; D is always zero.
 ; Sets Z on success.
 parseBinaryLiteral:
 	call	hasBinPrefix
 	ret	nz
 	push	bc
 	push	hl
-	push	de
 	ld	d, 0
 	inc	hl	; get rid of "0b"
 	inc	hl
@@ -236,8 +233,6 @@ parseBinaryLiteral:
 .error:
 	call	unsetZ
 .end:
-	push	de \ pop ix
-	pop	de
 	pop	hl
 	pop	bc
 	ret
@@ -255,7 +250,7 @@ hasBinPrefix:
 	ret
 
 ; Parse string at (HL) and, if it is a char literal, sets Z and return
-; corresponding value in IX. High IX byte is always clear.
+; corresponding value in E. D is always zero.
 ;
 ; A valid char literal starts with ', ends with ' and has one character in the
 ; middle. No escape sequence are accepted, but ''' will return the apostrophe
@@ -266,7 +261,6 @@ parseCharLiteral:
 	ret	nz
 
 	push	hl
-	push	de
 	inc	hl
 	inc	hl
 	cp	(hl)
@@ -283,12 +277,10 @@ parseCharLiteral:
 	ld	e, a
 	cp	a		; ensure Z
 .end:
-	push	de \ pop ix
-	pop	de
 	pop	hl
 	ret
 
-; Parses the string at (HL) and returns the 16-bit value in IX. The string
+; Parses the string at (HL) and returns the 16-bit value in DE. The string
 ; can be a decimal literal (1234), a hexadecimal literal (0x1234) or a char
 ; literal ('X').
 ;

apps/zasm/avr.asm

@@ -657,7 +657,6 @@ _readDouble:
 _readk7:
 	push	hl
 	push	de
-	push	ix
 	call	parseExpr
 	jr	nz, .end
 	; If we're in first pass, stop now. The value of HL doesn't matter and
@@ -686,7 +685,6 @@ _readk7:
 	ld	a, l
 	cp	a		; ensure Z
 .end:
-	pop	ix
 	pop	de
 	pop	hl
 	ret
@@ -707,7 +705,6 @@ _readR4:
 ; Set Z for success.
 _readR5:
 	push	de
-	push	ix
 	ld	a, (hl)
 	call	upcase
 	cp	'R'
@@ -715,11 +712,9 @@ _readR5:
 	inc	hl
 	call	parseDecimal
 	jr	nz, .end
-	push	ix \ pop de
 	ld	a, 31
 	call	_DE2A
 .end:
-	pop	ix
 	pop	de
 	ret
 

apps/zasm/parse.asm

@@ -1,5 +1,5 @@
 ; Parse string in (HL) and return its numerical value whether its a number
-; literal or a symbol. Returns value in IX.
+; literal or a symbol. Returns value in DE.
 ; Sets Z if number or symbol is valid, unset otherwise.
 parseNumberOrSymbol:
 	call	parseLiteral
@@ -14,31 +14,25 @@ parseNumberOrSymbol:
 	cp	'@'
 	jr	nz, .symbol
 	; last val
-	ld	ix, (DIREC_LASTVAL)
+	ld	de, (DIREC_LASTVAL)
 	ret
 .symbol:
-	push	de		; --> lvl 1
 	call	symFindVal	; --> DE
 	jr	nz, .notfound
-	; value in DE. We need it in IX
-	push	de \ pop ix
-	pop	de		; <-- lvl 1
-	cp	a		; ensure Z
 	ret
 .notfound:
-	pop	de		; <-- lvl 1
 	; If not found, check if we're in first pass. If we are, it doesn't
 	; matter that we didn't find our symbol. Return success anyhow.
 	; Otherwise return error. Z is already unset, so in fact, this is the
 	; same as jumping to zasmIsFirstPass
-	; however, before we do, load IX with zero. Returning dummy non-zero
+	; however, before we do, load DE with zero. Returning dummy non-zero
 	; values can have weird consequence (such as false overflow errors).
-	ld	ix, 0
+	ld	de, 0
 	jp	zasmIsFirstPass
 
 .returnPC:
 	push	hl
 	call	zasmGetPC
-	push	hl \ pop ix
+	ex	de, hl	; result in DE
 	pop	hl
 	ret