zasm: remove the "token" variable

apps/zasm/instr.asm

@@ -415,14 +415,12 @@ matchArg:
 	dec	hl
 	ret
 
-; Compare primary row at (DE) with ID at (token+1). Sets Z flag if there's a
-; match, reset if not.
+; Compare primary row at (DE) with ID in A. Sets Z flag if there's a match.
 matchPrimaryRow:
 	push	hl
 	push	ix
 	ld	ixh, d
 	ld	ixl, e
-	ld	a, (token+1)
 	cp	(ix)
 	jr	nz, .end
 	; name matches, let's see the rest
@@ -778,18 +776,22 @@ processArg:
 	ld	a, ixh
 	ld	(de), a
 	cp	a		; ensure Z is set
-	pop	hl
-	ret
+	jr	.end
 .error:
 	call	JUMP_UNSETZ
+.end:
 	pop	hl
 	ret
 
 ; Parse instruction specified in A (I_* const) with args in (HL) and write
 ; resulting opcode(s) in (curUpcode). Returns the number of bytes written in A.
 parseInstruction:
+	push	bc
 	push	hl
 	push	de
+	; A is reused in matchPrimaryRow but that register is way too changing.
+	; Let's keep a copy in a more cosy register.
+	ld	c, a
 	ld	de, curArg1
 	call	processArg
 	jr	nz, .error
@@ -800,7 +802,7 @@ parseInstruction:
 	ld	de, instrTBl
 	ld	b, INSTR_TBL_CNT
 .loop:
-	ld	a, (de)
+	ld	a, c			; recall A param
 	call	matchPrimaryRow
 	jr	z, .match
 	ld	a, INSTR_TBL_ROWSIZE
@@ -819,6 +821,7 @@ parseInstruction:
 .end:
 	pop	de
 	pop	hl
+	pop	bc
 	ret
 
 

apps/zasm/main.asm

@@ -32,18 +32,15 @@ parseLine:
 
 	call	gotoNextNotBlankLine
 	jr	nz, .error
-	push	de
-	ld	de, token
 	call	tokenize
-	pop	de
-	ld	a, (token)	; TOK_*
+	ld	a, b		; TOK_*
 	cp	TOK_BAD
 	jr	z, .error
 	cp	TOK_INSTR
 	jr	z, .instr
 	jr	.error		; directive not supported yet
 .instr:
-	ld	a, (token+1)	; I_*
+	ld	a, c		; I_*
 	call	parseInstruction
 	or	a	; is zero?
 	jr	z, .error
@@ -62,9 +59,5 @@ parseLine:
 	ret
 
 ; *** Variables ***
-
-token:
-	.fill	5
-
 scratchpad:
 	.fill	0x20

apps/zasm/tok.asm

@@ -11,40 +11,35 @@ TOK_DIRECTIVE	.equ	0x02
 TOK_BAD		.equ	0xff
 
 ; *** Code ***
-; Parse line in (HL) and read the next token in (DE). The token is written on
-; two bytes. The first byte is a token type (TOK_* constants) and the second
-; byte is an ID specific to that token type.
-; If no token matches, TOK_BAD is written to (DE)
+; Parse line in (HL) and read the next token in BC. The token is written on
+; two bytes (B and C). B is a token type (TOK_* constants) and C is an ID
+; specific to that token type.
+; Advance HL to after the read word.
+; If no token matches, TOK_BAD is written to B
 tokenize:
-	xor	a
-	ld	(de), a
+	push	de
 	call	toWord
 	ld	a, 4
+	ld	de, scratchpad
 	call	readWord
-	ex	hl, de
+	push	hl		; Save advanced HL for later
+	ld	hl, scratchpad
 	call	getInstID
 	jr	z, .instr
 	call	getDirectiveID
 	jr	z, .direc
 	; no match
-	ex	hl, de		; swap it back
-	ld	a, TOK_BAD
-	ld	(de), a
-	ret
+	ld	b, TOK_BAD
+	jr	.end
 .instr:
-	ex	af, af'
-	ld	a, TOK_INSTR
+	ld	b, TOK_INSTR
 	jr	.end
 .direc:
-	ex	af, af'
-	ld	a, TOK_DIRECTIVE
-	jr	.end
+	ld	b, TOK_DIRECTIVE
 .end:
-	ex	hl, de		; swap it back
-	ld	(de), a
-	ex	af, af'
-	inc	de
-	ld	(de), a
+	ld	c, a
+	pop	hl
+	pop	de
 	ret
 
 ; Sets Z is A is ';', CR, LF, or null.