parseExpr --> parseExprDE: easy ones

Those replacements were trivially equivalent. For the other ones, an
examination of the context is necessary.

apps/basic/main.asm

@@ -222,9 +222,8 @@ basPRINT:
 	call	rdWord
 	push	hl		; --> lvl 1
 	ex	de, hl
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .parseError
-	push	ix \ pop de
 	ld	hl, SCRATCHPAD
 	call	fmtDecimalS
 	call	printstr
@@ -252,9 +251,8 @@ basGOTO:
 	ld	de, SCRATCHPAD
 	call	rdWord
 	ex	de, hl
-	call	parseExpr
+	call	parseExprDE
 	ret	nz
-	push	ix \ pop de
 	call	bufFind
 	jr	nz, .notFound
 	push	ix \ pop de
@@ -316,8 +314,8 @@ basINPUT:
 	call	spitQuoted
 	call	rdSep
 	call	stdioReadLine
-	call	parseExpr
-	ld	(VAR_TBL), ix
+	call	parseExprDE
+	ld	(VAR_TBL), de
 	call	printcrlf
 	cp	a		; ensure Z
 	ret

apps/basic/parse.asm

@@ -40,9 +40,8 @@ parseTruth:
 	ret
 
 .simple:
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .end
-	push	ix \ pop de
 	ld	a, d
 	or	e
 	jr	.success
@@ -136,8 +135,7 @@ parseTruth:
 	ret	nz
 	push	ix		; --> lvl 1. save (HL) value in stack.
 	ex	de, hl
-	call	parseExpr
+	call	parseExprDE
 	ret	nz
-	push	ix \ pop de
 	pop	hl		; <-- lvl 1. restore.
 	ret

apps/basic/var.asm

@@ -52,10 +52,9 @@ varTryAssign:
 	call	rdWord
 	ex	de, hl
 	; Now, evaluate that expression now in (HL)
-	call	parseExpr	; --> number in IX
+	call	parseExprDE	; --> number in DE
 	jr	nz, .exprErr
 	pop	af	; <-- lvl 4
-	push	ix \ pop de	; send number to DE
 	call	varAssign
 	xor	a	; ensure Z
 .end:

apps/zasm/avr.asm

@@ -657,19 +657,18 @@ _readk7:
 	push	hl
 	push	de
 	push	ix
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .end
 	; If we're in first pass, stop now. The value of HL doesn't matter and
 	; truncation checks might falsely fail.
 	call	zasmIsFirstPass
 	jr	z, .end
-	; IX contains an absolute value. Turn this into a -64/+63 relative
+	; DE contains an absolute value. Turn this into a -64/+63 relative
 	; value by subtracting PC from it. However, before we do that, let's
 	; add 0x7f to it, which we'll remove later. This will simplify bounds
 	; checks. (we use 7f instead of 3f because we deal in bytes here, not
 	; in words)
-	push	ix \ pop hl
-	ld	de, 0x7f
+	ld	hl, 0x7f
 	add	hl, de		; Carry cleared
 	ex	de, hl
 	call	zasmGetPC	; --> HL

apps/zasm/directive.asm

@@ -146,10 +146,9 @@ handleEQU:
 	call	readWord
 	jr	nz, .badfmt
 	ld	hl, scratchpad
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
 	ld	hl, DIREC_SCRATCHPAD
-	push	ix \ pop de
 	; Save value in "@" special variable
 	ld	(DIREC_LASTVAL), de
 	call	symRegisterConst	; A and Z set