zasm: parseExpr --> parseExprDE

apps/zasm/avr.asm

@@ -643,14 +643,15 @@ _readK8:
 	jr	_readExpr
 
 _readDouble:
-	push	ix
+	push	de
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .end
-	push	ix \ pop bc
+	ld	b, d
+	ld	c, e
 	; BC is already set. For good measure, let's set A to BC's MSB
 	ld	a, b
 .end:
-	pop	ix
+	pop	de
 	ret
 
 _readk7:
@@ -705,6 +706,7 @@ _readR4:
 ; read a rXX argument and return register number in A.
 ; Set Z for success.
 _readR5:
+	push	de
 	push	ix
 	ld	a, (hl)
 	call	upcase
@@ -713,43 +715,44 @@ _readR5:
 	inc	hl
 	call	parseDecimal
 	jr	nz, .end
+	push	ix \ pop de
 	ld	a, 31
-	call	_IX2A
+	call	_DE2A
 .end:
 	pop	ix
+	pop	de
 	ret
 
-; Put IX's LSB into A and, additionally, ensure that the new value is <=
+; Put DE's LSB into A and, additionally, ensure that the new value is <=
 ; than what was previously in A.
 ; Z for success.
-_IX2A:
+_DE2A:
-	push	ix \ pop hl
+	cp	e
-	cp	l
+	jp	c, unsetZ	; A < E
-	jp	c, unsetZ	; A < L
+	ld	a, d
-	ld	a, h
 	or	a
 	ret	nz		; should be zero
-	ld	a, l
+	ld	a, e
 	; Z set from "or a"
 	ret
 
 ; Read expr and return success only if result in under number given in A
 ; Z for success
 _readExpr:
-	push	ix
+	push	de
 	push	bc
 	ld	b, a
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .end
 	ld	a, b
-	call	_IX2A
+	call	_DE2A
 	jr	nz, .end
 	or	c
 	ld	c, a
 	cp	a		; ensure Z
 .end:
 	pop	bc
-	pop	ix
+	pop	de
 	ret
 
 ; Parse one of the following: X, Y, Z, X+, Y+, Z+, -X, -Y, -Z.

apps/zasm/directive.asm

@@ -40,6 +40,7 @@ dirHandlers:
 	.dw	handleBIN
 
 handleDB:
+	push	de
 	push	hl
 .loop:
 	call	readWord
@@ -47,20 +48,21 @@ handleDB:
 	ld	hl, scratchpad
 	call	enterDoubleQuotes
 	jr	z, .stringLiteral
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
-	push	ix \ pop hl
+	ld	a, d
-	ld	a, h
 	or	a		; cp 0
 	jr	nz, .overflow	; not zero? overflow
-	ld	a, l
+	ld	a, e
 	call	ioPutB
 	jr	nz, .ioError
 .stopStrLit:
 	call	readComma
 	jr	z, .loop
 	cp	a		; ensure Z
+.end:
 	pop	hl
+	pop	de
 	ret
 .ioError:
 	ld	a, SHELL_ERR_IO_ERROR
@@ -74,9 +76,8 @@ handleDB:
 .overflow:
 	ld	a, ERR_OVFL
 .error:
-	call	unsetZ
+	or	a		; unset Z
-	pop	hl
+	jr	.end
-	ret
 
 .stringLiteral:
 	ld	a, (hl)
@@ -89,24 +90,26 @@ handleDB:
 	jr	.stringLiteral
 
 handleDW:
+	push	de
 	push	hl
 .loop:
 	call	readWord
 	jr	nz, .badfmt
 	ld	hl, scratchpad
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
-	push	ix \ pop hl
+	ld	a, e
-	ld	a, l
 	call	ioPutB
 	jr	nz, .ioError
-	ld	a, h
+	ld	a, d
 	call	ioPutB
 	jr	nz, .ioError
 	call	readComma
 	jr	z, .loop
 	cp	a		; ensure Z
+.end:
 	pop	hl
+	pop	de
 	ret
 .ioError:
 	ld	a, SHELL_ERR_IO_ERROR
@@ -117,9 +120,8 @@ handleDW:
 .badarg:
 	ld	a, ERR_BAD_ARG
 .error:
-	call	unsetZ
+	or	a		; unset Z
-	pop	hl
+	jr	.end
-	ret
 
 handleEQU:
 	call	zasmIsLocalPass	; Are we in local pass? Then ignore all .equ.
@@ -178,14 +180,17 @@ handleEQU:
 	jp	readWord
 
 handleORG:
+	push	de
 	call	readWord
 	jr	nz, .badfmt
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
-	push	ix \ pop hl
+	ex	de, hl
 	ld	(DIREC_LASTVAL), hl
 	call	zasmSetOrg
 	cp	a		; ensure Z
+.end:
+	pop	de
 	ret
 .badfmt:
 	ld	a, ERR_BAD_FMT
@@ -193,31 +198,28 @@ handleORG:
 .badarg:
 	ld	a, ERR_BAD_ARG
 .error:
-	call	unsetZ
+	or	a		; unset Z
-	ret
+	jr	.end
 
 handleFIL:
 	call	readWord
 	jr	nz, .badfmt
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
-	push	bc	; --> lvl 1
+	ld	a, d
-	push	ix \ pop bc
-	ld	a, b
 	cp	0xd0
 	jr	nc, .overflow
 .loop:
-	ld	a, b
+	ld	a, d
-	or	c
+	or	e
 	jr	z, .loopend
 	xor	a
 	call	ioPutB
 	jr	nz, .ioError
-	dec	bc
+	dec	de
 	jr	.loop
 .loopend:
 	cp	a	; ensure Z
-	pop	bc	; <-- lvl 1
 	ret
 .ioError:
 	ld	a, SHELL_ERR_IO_ERROR
@@ -229,11 +231,11 @@ handleFIL:
 	ld	a, ERR_BAD_ARG
 	jp	unsetZ
 .overflow:
-	pop	bc	; <-- lvl 1
 	ld	a, ERR_OVFL
 	jp	unsetZ
 
 handleOUT:
+	push	de
 	push	hl
 	; Read our expression
 	call	readWord
@@ -241,12 +243,11 @@ handleOUT:
 	call	zasmIsFirstPass		; No .out during first pass
 	jr	z, .end
 	ld	hl, scratchpad
-	call	parseExpr
+	call	parseExprDE
 	jr	nz, .badarg
-	push	ix \ pop hl
+	ld	a, d
-	ld	a, h
 	out	(ZASM_DEBUG_PORT), a
-	ld	a, l
+	ld	a, e
 	out	(ZASM_DEBUG_PORT), a
 	jr	.end
 .badfmt:
@@ -255,9 +256,10 @@ handleOUT:
 .badarg:
 	ld	a, ERR_BAD_ARG
 .error:
-	call	unsetZ
+	or	a		; unset Z
 .end:
 	pop	hl
+	pop	de
 	ret
 
 handleINC:

apps/zasm/instr.asm

@@ -146,7 +146,7 @@ parseIXY:
 ; any argspec (A == 0 means arg is empty). A return value of 0xff means an
 ; error.
 ;
-; If the parsed argument is a number constant, 'N' is returned and IX contains
+; If the parsed argument is a number constant, 'N' is returned and DE contains
 ; the value of that constant.
 parseArg:
 	call	strlen
@@ -154,13 +154,8 @@ parseArg:
 	ret	z		; empty string? A already has our result: 0
 
 	push	bc
-	push	de
 	push	hl
 
-	; We always initialize IX to zero so that non-numerical args end up with
-	; a clean zero.
-	ld	ix, 0
-
 	ld	de, argspecTbl
 	; DE now points the the "argspec char" part of the entry, but what
 	; we're comparing in the loop is the string next to it. Let's offset
@@ -181,7 +176,7 @@ parseArg:
 	; (HL) has no parens
 	call	.maybeParseExpr
 	jr	nz, .nomatch
-	; We have a proper number in no parens. Number in IX.
+	; We have a proper number in no parens. Number in DE.
 	ld	a, 'N'
 	jr	.end
 .withParens:
@@ -208,23 +203,20 @@ parseArg:
 .parseNumberInParens:
 	call	.maybeParseExpr
 	jr	nz, .nomatch
-	; We have a proper number in parens. Number in IX
+	; We have a proper number in parens. Number in DE
-	; is '-' in B? if yes, we need to negate the low part of IX
+	; is '-' in B? if yes, we need to negate the low part of DE
 	ld	a, b
 	cp	'-'
-	jr	nz, .dontNegateIX
+	jr	nz, .dontNegateDE
-	; we need to negate the low part of IX
+	; we need to negate the low part of DE
 	; TODO: when parsing routines properly support unary negative numbers,
 	; We could replace this complicated scheme below with a nice hack where
 	; we start parsing our displacement number at the '+' and '-' char.
 
-	; HL isn't needed anymore and can be destroyed.
+	ld	a, e
-	push	ix \ pop hl
-	ld	a, l
 	neg
-	ld	l, a
+	ld	e, a
-	push	hl \ pop ix
+.dontNegateDE:
-.dontNegateIX:
 	ld	a, c	; M, x, or y
 	jr	.end
 .nomatch:
@@ -235,9 +227,13 @@ parseArg:
 	; found the matching argspec row. Our result is one byte left of DE.
 	dec	de
 	ld	a, (de)
+
+	; When we have non-numerical args, we set DE to zero to have a clean
+	; result.
+	ld	de, 0
+
 .end:
 	pop	hl
-	pop	de
 	pop	bc
 	ret
 
@@ -247,9 +243,10 @@ parseArg:
 	; harmless, but in some cases it causes false failures. For example,
 	; a "-" operator can cause is to falsely overflow and generate
 	; truncation error.
+	ld	de, 0			; in first pass, return a clean zero
 	call	zasmIsFirstPass
 	ret	z
-	jp	parseExpr
+	jp	parseExprDE
 
 ; Returns, with Z, whether A is a groupId
 isGroupId:
@@ -817,27 +814,18 @@ spitUpcode:
 	ld	(INS_UPCODE+2), a
 	ret
 
-; Parse argument in (HL) and place it in (DE)
+; Parse argument in (HL) and place it in (IX)
-; DE is not preserved
 ; Sets Z on success, reset on error.
 processArg:
 	call	parseArg
 	cp	0xff
 	jr	z, .error
-	ld	(de), a
+	ld	(ix), a
-	; When A is a number, IX is set with the value of that number. Because
+	; When A is a number, DE is set with the value of that number. Because
 	; We don't use the space allocated to store those numbers in any other
-	; occasion, we store IX there unconditonally, LSB first.
+	; occasion, we store DE there unconditonally, LSB first.
-	inc	de
+	ld	(ix+1), e
-	ex	(sp), ix	; (SP) is kept in IX and will be restored
+	ld	(ix+2), d
-	ex	(sp), hl	; old HL is on (SP)
-	ld	a, l
-	ld	(de), a
-	inc	de
-	ld	a, h
-	ld	(de), a
-	ex	(sp), hl	; restore old HL from (SP)
-	ex	(sp), ix	; restore old (SP) from IX
 	cp	a		; ensure Z
 	ret
 .error:
@@ -860,14 +848,14 @@ parseInstruction:
 	ld	(INS_CURARG2), a
 	call	readWord
 	jr	nz, .nomorearg
-	ld	de, INS_CURARG1
+	ld	ix, INS_CURARG1
 	call	processArg
 	jr	nz, .end	; A is set to error, Z is unset
 	call	readComma
 	jr	nz, .nomorearg
 	call	readWord
 	jr	nz, .badfmt
-	ld	de, INS_CURARG2
+	ld	ix, INS_CURARG2
 	call	processArg
 	jr	nz, .end	; A is set to error, Z is unset
 .nomorearg: