apps/basic/glue.asm

@@ -9,21 +9,15 @@
 
 	jp	basStart
 
-; RAM space used in different routines for short term processing.
-.equ	SCRATCHPAD_SIZE	0x20
-.equ	SCRATCHPAD	USER_RAMSTART
-
 .inc "core.asm"
 .inc "lib/util.asm"
 .inc "lib/ari.asm"
 .inc "lib/parse.asm"
 .inc "lib/fmt.asm"
-.equ	EXPR_PARSE	parseLiteralOrVar
+.equ	EXPR_PARSE	parseLiteral
 .inc "lib/expr.asm"
 .inc "basic/tok.asm"
-.equ	VAR_RAMSTART	SCRATCHPAD+SCRATCHPAD_SIZE
-.inc "basic/var.asm"
-.equ	BUF_RAMSTART	VAR_RAMEND
+.equ	BUF_RAMSTART	USER_RAMSTART
 .inc "basic/buf.asm"
 .equ	BAS_RAMSTART	BUF_RAMEND
 .inc "basic/main.asm"

apps/basic/main.asm

@@ -1,29 +1,28 @@
+; *** Constants ***
+.equ	BAS_SCRATCHPAD_SIZE	0x20
 ; *** Variables ***
 ; Value of `SP` when basic was first invoked. This is where SP is going back to
 ; on restarts.
 .equ	BAS_INITSP	BAS_RAMSTART
-; Pointer to next line to run. If nonzero, it means that the next line is
-; the first of the list. This is used by GOTO to indicate where to jump next.
-; Important note: this is **not** a line number, it's a pointer to a line index
-; in buffer. If it's not zero, its a valid pointer.
-.equ	BAS_PNEXTLN	@+2
-.equ	BAS_RAMEND	@+2
+; **Pointer** to current line number
+.equ	BAS_PCURLN	@+2
+.equ	BAS_SCRATCHPAD	@+2
+.equ	BAS_RAMEND	@+BAS_SCRATCHPAD_SIZE
 
 ; *** Code ***
 basStart:
 	ld	(BAS_INITSP), sp
-	call	varInit
 	call	bufInit
 	xor	a
-	ld	(BAS_PNEXTLN), a
-	ld	(BAS_PNEXTLN+1), a
 	ld	hl, .welcome
 	call	printstr
 	call	printcrlf
+	ld	hl, .welcome+2		; points to a zero word
+	ld	(BAS_PCURLN), hl
 	jr	basLoop
 
 .welcome:
-	.db "OK", 0
+	.db "OK", 0, 0
 
 basLoop:
 	ld	hl, .sPrompt
@@ -40,8 +39,8 @@ basLoop:
 	jr	basLoop
 .number:
 	push	ix \ pop de
-	call	toSep
-	call	rdSep
+	call	toWS
+	call	rdWS
 	call	bufAdd
 	jp	nz, basERR
 	jr	basLoop
@@ -53,10 +52,7 @@ basLoop:
 ; on success. Therefore, when calling basCallCmd results in NZ, we're not sure
 ; where the error come from, but well...
 basCallCmd:
-	; let's see if it's a variable assignment.
-	call	varTryAssign
-	ret	z	; Done!
-	; Second, get cmd length
+	; First, get cmd length
 	call	fnWSIdx
 	cp	7
 	jp	nc, unsetZ	; Too long, can't possibly fit anything.
@@ -83,13 +79,17 @@ basCallCmd:
 	ex	de, hl
 	ld	a, b	; cmd's length
 	call	addHL
-	call	rdSep
+	call	rdWS
 	jp	(ix)
 
+
+basPrintLn:
+	call	printstr
+	jp	printcrlf
+
 basERR:
 	ld	hl, .sErr
-	call	printstr
-	jp	printcrlf
+	jr	basPrintLn
 .sErr:
 	.db	"ERR", 0
 
@@ -102,8 +102,7 @@ basERR:
 ; Commands are expected to set Z on success.
 basBYE:
 	ld	hl, .sBye
-	call	printstr
-	call	printcrlf
+	call	basPrintLn
 	; To quit the loop, let's return the stack to its initial value and
 	; then return.
 	xor	a
@@ -118,7 +117,7 @@ basLIST:
 .loop:
 	ld	e, (ix)
 	ld	d, (ix+1)
-	ld	hl, SCRATCHPAD
+	ld	hl, BAS_SCRATCHPAD
 	call	fmtDecimal
 	call	printstr
 	ld	a, ' '
@@ -133,8 +132,6 @@ basLIST:
 
 
 basRUN:
-	call	.maybeGOTO
-	jr	nz, .loop	; IX already set
 	call	bufFirst
 	ret	nz
 .loop:
@@ -144,8 +141,6 @@ basRUN:
 	call	basCallCmd
 	pop	ix		; <-- lvl 1
 	jp	nz, .err
-	call	.maybeGOTO
-	jr	nz, .loop	; IX already set
 	call	bufNext
 	jr	z, .loop
 	cp	a		; ensure Z
@@ -154,69 +149,23 @@ basRUN:
 	; Print line number, then return NZ (which will print ERR)
 	ld	e, (ix)
 	ld	d, (ix+1)
-	ld	hl, SCRATCHPAD
+	ld	hl, BAS_SCRATCHPAD
 	call	fmtDecimal
 	call	printstr
 	ld	a, ' '
 	call	stdioPutC
 	jp	unsetZ
 
-; This returns the opposite Z result as the one we usually see: Z is set if
-; we **don't** goto, unset if we do. If we do, IX is properly set.
-.maybeGOTO:
-	ld	de, (BAS_PNEXTLN)
-	ld	a, d
-	or	e
-	ret	z
-	; we goto
-	push	de \ pop ix
-	; we need to reset our goto marker
-	ld	de, 0
-	ld	(BAS_PNEXTLN), de
-	ret
+.runline:
 
 basPRINT:
-	ld	de, SCRATCHPAD
-	call	rdWord
-	push	hl		; --> lvl 1
-	ex	de, hl
 	call	parseExpr
 	ret	nz
 	push	ix \ pop de
-	ld	hl, SCRATCHPAD
+	ld	hl, BAS_SCRATCHPAD
 	call	fmtDecimal
-	call	printstr
-	pop	hl		; <-- lvl 1
-	; Do we have another arg?
-	call	rdSep
-	jr	z, .another
-	; no, we can stop here
 	cp	a		; ensure Z
-	jp	printcrlf
-.another:
-	; Before we jump to basPRINT, let's print a space
-	ld	a, ' '
-	call	stdioPutC
-	jr	basPRINT
-
-basGOTO:
-	ld	de, SCRATCHPAD
-	call	rdWord
-	ex	de, hl
-	call	parseExpr
-	ret	nz
-	push	ix \ pop de
-	call	bufFind
-	jr	nz, .notFound
-	push	ix \ pop de
-	; Z already set
-	jr	.end
-.notFound:
-	ld	de, 0
-	; Z already unset
-.end:
-	ld	(BAS_PNEXTLN), de
-	ret
+	jp	basPrintLn
 
 ; direct only
 basCmds1:
@@ -230,6 +179,4 @@ basCmds1:
 basCmds2:
 	.dw	basPRINT
 	.db	"print", 0
-	.dw	basGOTO
-	.db	"goto", 0, 0
 	.db	0xff, 0xff, 0xff	; end of table

apps/basic/tok.asm

@@ -1,12 +1,3 @@
-; Sets Z is A is ' ' or '\t' (whitespace), or ',' (arg sep)
-isSep:
-	cp	' '
-	ret	z
-	cp	0x09
-	ret	z
-	cp	','
-	ret
-
 ; Expect at least one whitespace (0x20, 0x09) at (HL), and then advance HL
 ; until a non-whitespace character is met.
 ; HL is advanced to the first non-whitespace char.
@@ -14,7 +5,7 @@ isSep:
 ; Failure is either not having a first whitespace or reaching the end of the
 ; string.
 ; Sets Z if we found a non-whitespace char, unset if we found the end of string.
-rdSep:
+rdWS:
 	ld	a, (hl)
 	call	isSep
 	ret	nz	; failure
@@ -56,32 +47,10 @@ fnWSIdx:
 	pop	hl
 	ret
 
-; Advance HL to the next separator or to the end of string.
-toSep:
+; Advance HL to the next whitespace or to the end of string.
+toWS:
 	ld	a, (hl)
 	call	isSep
 	ret	z
 	inc	hl
-	jr	toSep
-
-; Read (HL) until the next separator and copy it in (DE)
-; DE is preserved, but HL is advanced to the end of the read word.
-rdWord:
-	push	af
-	push	de
-.loop:
-	ld	a, (hl)
-	call	isSep
-	jr	z, .stop
-	or	a
-	jr	z, .stop
-	ld	(de), a
-	inc	hl
-	inc	de
-	jr	.loop
-.stop:
-	xor	a
-	ld	(de), a
-	pop	de
-	pop	af
-	ret
+	jr	toWS

apps/basic/var.asm

@@ -1,101 +0,0 @@
-; *** Variables ***
-; A list of words for each member of the A-Z range.
-.equ	VAR_TBL		VAR_RAMSTART
-.equ	VAR_RAMEND	@+52
-
-; *** Code ***
-
-varInit:
-	ld	b, VAR_RAMEND-VAR_RAMSTART
-	ld	hl, VAR_RAMSTART
-	xor	a
-.loop:
-	ld	(hl), a
-	inc	hl
-	djnz	.loop
-	ret
-
-; Check if A is a valid variable letter (a-z or A-Z). If it is, set A to a
-; valid VAR_TBL index and set Z. Otherwise, unset Z (and A is destroyed)
-varChk:
-	call	upcase
-	sub	'A'
-	ret	c	; Z unset
-	cp	27	; 'Z' + 1
-	jr	c, .isVar
-	; A > 'Z'
-	dec	a	; unset Z
-	ret
-.isVar:
-	cp	a	; set Z
-	ret
-
-; Try to interpret line at (HL) and see if it's a variable assignment. If it
-; is, proceed with the assignment and set Z. Otherwise, NZ.
-varTryAssign:
-	inc	hl
-	ld	a, (hl)
-	dec	hl
-	cp	'='
-	ret	nz
-	ld	a, (hl)
-	call	varChk
-	ret	nz
-	; We have a variable! Its table index is currently in A.
-	push	ix	; --> lvl 1
-	push	hl	; --> lvl 2
-	push	de	; --> lvl 3
-	push	af	; --> lvl 4. save for later
-	; Let's put that expression to read in scratchpad
-	inc	hl \ inc hl
-	ld	de, SCRATCHPAD
-	call	rdWord
-	ex	de, hl
-	; Now, evaluate that expression now in (HL)
-	call	parseExpr	; --> number in IX
-	jr	nz, .exprErr
-	pop	af	; <-- lvl 4
-	add	a, a	; * 2 because each element is a word
-	ld	hl, VAR_TBL
-	call	addHL
-	; HL placed, write number
-	push	ix \ pop de
-	ld	(hl), e
-	inc	hl
-	ld	(hl), d
-	xor	a	; ensure Z
-.end:
-	pop	de	; <-- lvl 3
-	pop	hl	; <-- lvl 2
-	pop	ix	; <-- lvl 1
-	ret
-.exprErr:
-	pop	af	; <-- lvl 4
-	jr	.end
-
-; Check if value at (HL) is a variable. If yes, returns its associated value.
-; Otherwise, jump to parseLiteral.
-parseLiteralOrVar:
-	inc	hl
-	ld	a, (hl)
-	dec	hl
-	or	a
-	; if more than one in length, it can't be a variable
-	jp	nz, parseLiteral
-	ld	a, (hl)
-	call	varChk
-	jp	nz, parseLiteral
-	; It's a variable, resolve!
-	add	a, a	; * 2 because each element is a word
-	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/parse.asm

@@ -132,7 +132,7 @@ parseDecimal:
 	pop	hl
 	ret	z
 	; A is not 0? Ok, but if it's a space, we're happy too.
-	jp	isWS
+	jp	isSep
 .error:
 	pop	hl
 	jp	unsetZ

apps/lib/util.asm

@@ -1,5 +1,5 @@
-; Sets Z is A is ' ' or '\t' (whitespace)
-isWS:
+; Sets Z is A is ' ' or '\t'
+isSep:
 	cp	' '
 	ret	z
 	cp	0x09

apps/zasm/tok.asm

@@ -31,7 +31,7 @@ isLineEnd:
 
 ; Sets Z is A is ' ', ',', ';', CR, LF, or null.
 isSepOrLineEnd:
-	call	isWS
+	call	isSep
 	ret	z
 	jr	isLineEndOrComment
 
@@ -68,7 +68,7 @@ isLabel:
 ; read char in A
 _eatWhitespace:
 	call	ioGetB
-	call	isWS
+	call	isSep
 	ret	nz
 	jr	_eatWhitespace