zasm: add ERR_BAD_FMT

apps/zasm/const.asm

@@ -6,3 +6,5 @@
 ; contains references to undefined symbols.
 .equ	ERR_BAD_ARG		0x02
 
+; Code is badly formatted (comma without a following arg, unclosed quote, etc.)
+.equ	ERR_BAD_FMT		0x03

apps/zasm/instr.asm

@@ -791,7 +791,7 @@ parseInstruction:
 	call	readComma
 	jr	nz, .nomorearg
 	call	readWord
-	jr	nz, .error
+	jr	nz, .badfmt
 	ld	de, curArg2
 	call	processArg
 	jr	nz, .error	; A is set to error
@@ -824,6 +824,8 @@ parseInstruction:
 	djnz	.loopWrite
 	cp	a	; ensure Z
 	jr	.end
+.badfmt:
+	ld	a, ERR_BAD_FMT
 .error:
 	; A is set to error already
 	call	unsetZ

tools/tests/zasm/errtests.sh

@@ -18,3 +18,5 @@ chkerr() {
 
 chkerr "foo" 1
 chkerr "ld a, foo" 2
+chkerr "ld a," 3
+chkerr "ld a, 'A" 3