zasm: simplify readWord calling

It always reads in the scratchpad with the same max size. No need for
DE-dancing anymore.

apps/zasm/directive.asm

@@ -17,11 +17,8 @@ directiveHandlers:
 	.dw	handleDW
 
 handleDB:
-	push	de
 	push	hl
 	call	toWord
-	ld	de, scratchpad
-	ld	a, 8
 	call	readWord
 	ld	hl, scratchpad
 	call	parseNumber
@@ -29,15 +26,11 @@ handleDB:
 	ld	(direcData), a
 	ld	a, 1
 	pop	hl
-	pop	de
 	ret
 
 handleDW:
-	push	de
 	push	hl
 	call	toWord
-	ld	de, scratchpad
-	ld	a, 8
 	call	readWord
 	ld	hl, scratchpad
 	call	parseNumber
@@ -47,7 +40,6 @@ handleDW:
 	ld	(direcData+1), a
 	ld	a, 2
 	pop	hl
-	pop	de
 	ret
 
 ; Reads string in (HL) and returns the corresponding ID (D_*) in A. Sets Z if

apps/zasm/emul/Makefile

@@ -8,5 +8,5 @@ libz80/libz80.o: libz80/z80.c
 kernel.h: glue.asm
 	scas -o - -I ../../../parts/z80 $< | ./bin2c.sh KERNEL | tee $@ > /dev/null
 
-zasm.h: $(addprefix ../, main.asm instr.asm directive.asm tok.asm literal.asm util.asm)
+zasm.h: $(addprefix ../, main.asm instr.asm directive.asm tok.asm parse.asm literal.asm util.asm)
 	scas -o - -I.. $< | ./bin2c.sh ZASM | tee $@ > /dev/null

apps/zasm/instr.asm

@@ -688,17 +688,11 @@ getUpcode:
 ; Parse next argument in string (HL) and place it in (DE)
 ; Sets Z on success, reset on error.
 processArg:
-	push	de
 	call	toWord
-	xor	a
-	ld	de, scratchpad
-	ld	(de), a
-	ld	a, 8
 	call	readWord
-	pop	de
-	; Read word is in scratchpad, (DE) is back to initial value, HL is
-	; properly advanced. Now, let's push that HL value and replace it with
-	; (scratchpad) so that we can parse that arg.
+	; Read word is in scratchpad, HL is properly advanced. Now, let's push
+	; that HL value and replace it with (scratchpad) so that we can parse
+	; that arg.
 	push	hl
 	ld	hl, scratchpad
 

apps/zasm/main.asm

@@ -20,6 +20,7 @@ main:
 	ret
 
 #include "util.asm"
+#include "parse.asm"
 #include "literal.asm"
 #include "instr.asm"
 #include "tok.asm"
@@ -76,6 +77,3 @@ parseLine:
 	pop	bc
 	ret
 
-; *** Variables ***
-scratchpad:
-	.fill	0x20

apps/zasm/parse.asm

@@ -0,0 +1,128 @@
+; *** Consts ***
+.equ	SCRATCHPAD_SIZE	0x20
+; *** Variables ***
+scratchpad:
+	.fill	SCRATCHPAD_SIZE
+
+; *** Code ***
+
+; Sets Z is A is ';', CR, LF, or null.
+isLineEndOrComment:
+	cp	';'
+	ret	z
+	; Continues onto isLineEnd...
+
+; Sets Z is A is CR, LF, or null.
+isLineEnd:
+	or	a	; same as cp 0
+	ret	z
+	cp	0x0d
+	ret	z
+	cp	0x0a
+	ret
+
+; Sets Z is A is ' ' '\t' or ','
+isSep:
+	cp	' '
+	ret	z
+	cp	0x09
+	ret	z
+	cp	','
+	ret
+
+; Sets Z is A is ' ', ',', ';', CR, LF, or null.
+isSepOrLineEnd:
+	call	isSep
+	ret	z
+	call	isLineEndOrComment
+	ret
+
+; read word in (HL) and put it in (scratchpad), null terminated, for a maximum
+; of SCRATCHPAD_SIZE-1 characters. As a result, A is the read length. HL is
+; advanced to the next separator char.
+readWord:
+	push	bc
+	push	de
+	ld	de, scratchpad
+	ld	b, SCRATCHPAD_SIZE-1
+.loop:
+	ld	a, (hl)
+	call	isSepOrLineEnd
+	jr	z, .success
+	call	JUMP_UPCASE
+	ld	(de), a
+	inc	hl
+	inc	de
+	djnz	.loop
+.success:
+	xor	a
+	ld	(de), a
+	ld	a, SCRATCHPAD_SIZE-1
+	sub	a, b
+.end:
+	pop	de
+	pop	bc
+	ret
+
+; (HL) being a string, advance it to the next non-sep character.
+; Set Z if we could do it before the line ended, reset Z if we couldn't.
+toWord:
+.loop:
+	ld	a, (hl)
+	call	isLineEndOrComment
+	jr	z, .error
+	call	isSep
+	jr	nz, .success
+	inc	hl
+	jr	.loop
+.error:
+	call	JUMP_UNSETZ
+	ret
+.success:
+	xor	a	; ensure Z
+	ret
+
+; Advance HL to the beginning of the next line, that is, right after the next
+; 0x10 or 0x13 or both. If we reach null, we stop and error out.
+; Sets Z on success, unsets it on error.
+gotoNextLine:
+	dec	hl	; a bit weird, but makes the looping easier
+.loop:
+	inc	hl
+	ld	a, (hl)
+	call	isLineEnd
+	jr	nz, .loop
+	; (HL) is 0x10, 0x13 or 0
+	or	a	; is 0?
+	jr	z, .error
+	; we might have 0x13 followed by 0x10, let's account for this.
+	; Yes, 0x10 followed by 0x10 will make us skip two lines, but this is of
+	; no real consequence in our context.
+	inc	hl
+	ld	a, (hl)
+	call	isLineEnd
+	jr	nz, .success
+	or	a	; is 0?
+	jr	z, .error
+	; There was another line sep. Skip this char
+	inc	hl
+	; Continue on to .success
+.success:
+	xor	a	; ensure Z
+	ret
+.error:
+	call	JUMP_UNSETZ
+	ret
+
+; Repeatedly calls gotoNextLine until the line in (HL) points to a line that
+; isn't blank or 100% comment. Sets Z if we reach a line, Unset Z if we reach
+; EOF
+gotoNextNotBlankLine:
+	call	toWord
+	ret	z	; Z set? we have a not-blank line
+	; Z not set? (HL) is at the end of the line or at the beginning of
+	; comments.
+	call	gotoNextLine
+	ret	nz
+	jr	gotoNextNotBlankLine
+

apps/zasm/tok.asm

@@ -1,7 +1,3 @@
-; tok
-;
-; Tokenizes an ASM source file into 1, 2 or 3-sized structures.
-;
 ; *** Requirements ***
 ; JUMP_UPCASE
 
@@ -17,10 +13,7 @@ TOK_BAD		.equ	0xff
 ; Advance HL to after the read word.
 ; If no token matches, TOK_BAD is written to B
 tokenize:
-	push	de
 	call	toWord
-	ld	a, 4
-	ld	de, scratchpad
 	call	readWord
 	push	hl		; Save advanced HL for later
 	ld	hl, scratchpad
@@ -39,125 +32,4 @@ tokenize:
 .end:
 	ld	c, a
 	pop	hl
-	pop	de
 	ret
-
-; Sets Z is A is ';', CR, LF, or null.
-isLineEndOrComment:
-	cp	';'
-	ret	z
-	; Continues onto isLineEnd...
-
-; Sets Z is A is CR, LF, or null.
-isLineEnd:
-	or	a	; same as cp 0
-	ret	z
-	cp	0x0d
-	ret	z
-	cp	0x0a
-	ret
-
-; Sets Z is A is ' ' '\t' or ','
-isSep:
-	cp	' '
-	ret	z
-	cp	0x09
-	ret	z
-	cp	','
-	ret
-
-; Sets Z is A is ' ', ',', ';', CR, LF, or null.
-isSepOrLineEnd:
-	call	isSep
-	ret	z
-	call	isLineEndOrComment
-	ret
-
-; read word in (HL) and put it in (DE), null terminated, for a maximum of A
-; characters. As a result, A is the read length. HL is advanced to the next
-; separator char.
-readWord:
-	push	bc
-	push	de
-	ld	b, a
-.loop:
-	ld	a, (hl)
-	call	isSepOrLineEnd
-	jr	z, .success
-	call	JUMP_UPCASE
-	ld	(de), a
-	inc	hl
-	inc	de
-	djnz	.loop
-.success:
-	xor	a
-	ld	(de), a
-	ld	a, 4
-	sub	a, b
-.end:
-	pop	de
-	pop	bc
-	ret
-
-; (HL) being a string, advance it to the next non-sep character.
-; Set Z if we could do it before the line ended, reset Z if we couldn't.
-toWord:
-.loop:
-	ld	a, (hl)
-	call	isLineEndOrComment
-	jr	z, .error
-	call	isSep
-	jr	nz, .success
-	inc	hl
-	jr	.loop
-.error:
-	call	JUMP_UNSETZ
-	ret
-.success:
-	xor	a	; ensure Z
-	ret
-
-; Advance HL to the beginning of the next line, that is, right after the next
-; 0x10 or 0x13 or both. If we reach null, we stop and error out.
-; Sets Z on success, unsets it on error.
-gotoNextLine:
-	dec	hl	; a bit weird, but makes the looping easier
-.loop:
-	inc	hl
-	ld	a, (hl)
-	call	isLineEnd
-	jr	nz, .loop
-	; (HL) is 0x10, 0x13 or 0
-	or	a	; is 0?
-	jr	z, .error
-	; we might have 0x13 followed by 0x10, let's account for this.
-	; Yes, 0x10 followed by 0x10 will make us skip two lines, but this is of
-	; no real consequence in our context.
-	inc	hl
-	ld	a, (hl)
-	call	isLineEnd
-	jr	nz, .success
-	or	a	; is 0?
-	jr	z, .error
-	; There was another line sep. Skip this char
-	inc	hl
-	; Continue on to .success
-.success:
-	xor	a	; ensure Z
-	ret
-.error:
-	call	JUMP_UNSETZ
-	ret
-
-; Repeatedly calls gotoNextLine until the line in (HL) points to a line that
-; isn't blank or 100% comment. Sets Z if we reach a line, Unset Z if we reach
-; EOF
-gotoNextNotBlankLine:
-	call	toWord
-	ret	z	; Z set? we have a not-blank line
-	; Z not set? (HL) is at the end of the line or at the beginning of
-	; comments.
-	call	gotoNextLine
-	ret	nz
-	jr	gotoNextNotBlankLine
-