basic: make cmd table more compact

This shaves off quite a few bytes from the binary.

apps/basic/blk.asm

@@ -38,12 +38,12 @@ basPUTB:
 	jp	blkPutB
 
 basBLKCmds:
+	.db	"bsel", 0
 	.dw	basBSEL
-	.db	"bsel", 0, 0
-	.dw	basBSEEK
 	.db	"bseek", 0
+	.dw	basBSEEK
+	.db	"getb", 0
 	.dw	basGETB
-	.db	"getb", 0, 0
+	.db	"putb", 0
 	.dw	basPUTB
-	.db	"putb", 0, 0
-	.db	0xff, 0xff, 0xff	; end of table
+	.db	0xff		; end of table

apps/basic/fs.asm

@@ -127,14 +127,14 @@ basPgmHook:
 	ret
 
 basFSCmds:
+	.db	"fls", 0
 	.dw	basFLS
-	.db	"fls", 0, 0, 0
-	.dw	basLDBAS
 	.db	"ldbas", 0
-	.dw	basFOPEN
+	.dw	basLDBAS
 	.db	"fopen", 0
+	.dw	basFOPEN
+	.db	"fnew", 0
 	.dw	basFNEW
-	.db	"fnew", 0, 0
+	.db	"fdel", 0
 	.dw	basFDEL
-	.db	"fdel", 0, 0
-	.db	0xff, 0xff, 0xff	; end of table
+	.db	0xff		; end of table

apps/basic/main.asm

@@ -63,19 +63,18 @@ basLoop:
 ; Destroys HL.
 ; Z is set if found, unset otherwise.
 basFindCmd:
-	; cmd table starts with routine pointer, skip
-	inc	hl \ inc hl
 .loop:
 	call	strcmp
-	jr	z, .found
-	ld	a, 8
-	call	addHL
+	call	strskip
+	inc	hl		; point to routine
+	jr	z, .found	; Z from strcmp
+	inc	hl \ inc hl	; skip routine
 	ld	a, (hl)
-	cp	0xff
-	jr	nz, .loop
-	jp	unsetZ
+	inc	a		; was it 0xff?
+	jr	nz, .loop	; no
+	dec	a		; unset Z
+	ret
 .found:
-	dec	hl \ dec hl
 	call	intoHL
 	push	hl \ pop ix
 	ret
@@ -436,46 +435,49 @@ basR2Var:	; Just send reg to vars. Used in basPgmHook
 	cp	a		; USR never errors out
 	ret
 
+; Command table format: Null-terminated string followed by a 2-byte routine
+; pointer.
+
 ; direct only
 basCmds1:
+	.db	"bye", 0
 	.dw	basBYE
-	.db	"bye", 0, 0, 0
+	.db	"list", 0
 	.dw	basLIST
-	.db	"list", 0, 0
+	.db	"run", 0
 	.dw	basRUN
-	.db	"run", 0, 0, 0
-	.dw	bufInit
 	.db	"clear", 0
+	.dw	bufInit
 ; statements
 basCmds2:
-	.dw	basPRINT
 	.db	"print", 0
+	.dw	basPRINT
+	.db	"goto", 0
 	.dw	basGOTO
-	.db	"goto", 0, 0
+	.db	"if", 0
 	.dw	basIF
-	.db	"if", 0, 0, 0, 0
-	.dw	basINPUT
 	.db	"input", 0
+	.dw	basINPUT
+	.db	"peek", 0
 	.dw	basPEEK
-	.db	"peek", 0, 0
+	.db	"poke", 0
 	.dw	basPOKE
-	.db	"poke", 0, 0
+	.db	"deek", 0
 	.dw	basDEEK
-	.db	"deek", 0, 0
+	.db	"doke", 0
 	.dw	basDOKE
-	.db	"doke", 0, 0
+	.db	"out", 0
 	.dw	basOUT
-	.db	"out", 0, 0, 0
+	.db	"in", 0
 	.dw	basIN
-	.db	"in", 0, 0, 0, 0
+	.db	"getc", 0
 	.dw	basGETC
-	.db	"getc", 0, 0
+	.db	"putc", 0
 	.dw	basPUTC
-	.db	"putc", 0, 0
-	.dw	basSLEEP
 	.db	"sleep", 0
+	.dw	basSLEEP
+	.db	"addr", 0
 	.dw	basADDR
-	.db	"addr", 0, 0
+	.db	"usr", 0
 	.dw	basUSR
-	.db	"usr", 0, 0, 0
-	.db	0xff, 0xff, 0xff	; end of table
+	.db	0xff	; end of table

apps/lib/util.asm

@@ -52,6 +52,19 @@ strcmp:
 	; early, set otherwise)
 	ret
 
+; Given a string at (HL), move HL until it points to the end of that string.
+strskip:
+	push	af
+	xor	a	; look for null char
+.loop:
+	cp	(hl)
+	jp	z, .found
+	inc	hl
+	jr	.loop
+.found:
+	pop	af
+	ret
+
 ; Returns length of string at (HL) in A.
 ; Doesn't include null termination.
 strlen: