Errors

The table below lists the errors that Monster may report while assembling, linking, debugging, or performing file I/O. Each error has a numeric code and an on-screen message. Some messages are self-explanatory; others are described in more detail below.

CODE	MESSAGE	DESCRIPTION
1	STACK UNDERFLOW	Monster uses stacks for various things (e.g. nested .IF directives); a context-dependent stack has underflowed
2	STACK OVERFLOW	as above, but a context-dependent stack has overflowed
3	OVERSIZED LINE	a line was found that is over the maximum length of 40 characters
4	INVALID EXPRESSION	the expression could not be successfully parsed
5	INVALID MACRO ARGS	the macro was invoked with the wrong number of, or invalid, arguments
6	SYNTAX ERROR	general error; typically means an instruction is malformed
7	INVALID DIRECTIVE	a .-prefixed string was encountered, signifying a directive, but it doesn’t match any of the known directives
8	LABEL UNDEFINED	an attempt was made to look up a label with a name that no label exists for
9	ENDIF WITH NO IF	an .ENDIF directive was encountered, but it has no matching .IF directive
10	TOO MANY MACROS	the maximum number of macros (128) has been exceeded
11	LABEL NOT LEFT ALIGNED	something that looks like a label definition was found, but it is not in the leftmost column
12	INVALID OPCODE	something that looks like an opcode was found, but it does not match any known opcode
13	INVALID ADDR MODE	the address mode used for an instruction is not legal for that opcode (e.g. sty $1000,x)
14	OVERSIZED OPERAND	the operand for an instruction is too big (e.g. lda #500)
15	INVALID LABEL	a label definition was found, but it contains invalid characters
16	LABEL TOO LONG	a label definition was found, but it exceeds the maximum length (16 characters)
17	UNEXPECTED CHAR	a garbage character was encountered; the instruction or operand may be malformed
18	EXPECTED VALUE	a value was expected but none was found (e.g. a missing operand)
19	I/O ERROR	general-purpose error from disk access
20	NO MACRO NAME	a macro definition was made, but it is missing a name (1st parameter)
21	LABEL UNRESOLVABLE	a label was referenced in the second assembly pass, but the assembler still hasn’t seen a definition for it
22	CYCLIC INCLUDE	a file includes itself, directly or indirectly
23	FAILED TO OPEN INCLUDE FILE	an .INC directive was found, but the file it references could not be found/opened
24	SEGMENT OVERLAP	two segments overlap in the final linked layout
25	TOO MANY FILES	there are too many files
26	PARAM NAME TOO LONG	a macro’s parameter name is too long — parameter names must be 16 characters at most
27	LINE NOT FOUND FOR ADDRESS	no line was found for the address that was used to look one up
28	ORIGIN UNSET	an instruction was found before the program was given an origin (.ORG)
29	RANGE ERROR	branch target is too far; relative branch targets must be within [-128, 127] bytes of the branch
30	FILE NOT FOUND	a file was not found for the requested filename
31	UNKNOWN SEGMENT	a segment was referenced that is not defined (linker)
32	IMPORT UNDEFINED	an imported symbol has no matching export at link time
33	PC TARGET UNWRITABLE	the PC has reached an address that is not writable (e.g. ROM), so the assembler cannot write to it
34	CANNOT REDUCE EXPRESSION	an expression contains an invalid combination of relative and absolute references; define the symbol ahead of its usage so it is resolvable
35	TOO MANY OPEN FILES	the maximum number of files that may be open (15) has been exceeded
36	LOGICAL FILE IN USE	the logical file number is already in use
37	NO DRIVE RESPONSE	the selected disk drive did not respond
38	FILE TOO BIG	the file requested to be loaded is too big to fit in a source buffer (24KB)
39	UNNAMED BUFFER	an operation (e.g. producing debug information for a line) requires the buffer to have a name, but it has none
40	TOO MANY OPEN BUFFERS	the maximum number of source buffers (8) is already open
41	NO FILENAME	the command requires a filename (e.g. SAVE), but none was given
42	NO OPEN SCOPE	a local label was defined, but there is no open scope for it to be defined under
43	LABEL ALREADY DEFINED	a label with the name of another one already exists
44	TOO MANY LABELS	the maximum number of named labels (640) has been exceeded
45	LABEL NOT KNOWN IN PASS 1	the address of a label was incorrectly inferred in pass 1; typically an operand assumed absolute turned out to be zero page
46	INVALID COMMAND	an invalid monitor command was provided
47	COPY TOO BIG	a copy was attempted that exceeded the maximum size
48	BUFFER NAME EXISTS	the buffer could not be given the suggested name because a buffer of the same name is already loaded
49	BUFFER FULL	an insertion into a buffer could not be completed because the buffer is already full
50	TOO MANY GLOBAL REFS	the linker’s global reference table has been exceeded
51	TOO MANY SEGMENTS	the maximum number of segments (64) has been exceeded (linker)
52	SECTION OVERRUN	a section is too small to hold the segments assigned to it (linker)
53	CONFLICTING ADDRESS MODES FOR SYMBOL	a symbol was defined/used with conflicting address modes (zero page vs absolute) across object files
54	MULTIPLE DEFINITIONS FOR SYMBOL	a symbol is exported (defined) in more than one object file
55	UNKNOWN TYPE	an unknown segment TYPE was specified in the LINK file
56	UNEXPECTED TYPE	a segment TYPE was used somewhere it is not allowed
57	CONFLICTING SEGMENT TYPES	a segment was declared with conflicting types across object files
58	BSS SEGMENT CONTAINS NONZERO DATA	a BSS segment (which must be uninitialized) contains nonzero data
59	OUT OF MEMORY	a buffer (context-dependent) has run out of memory
60	CONTEXT FULL	an internal context buffer is full
61	NO MATCHING SCOPE	a scope-closing construct has no matching open scope
62	FILENAME TOO LONG	a filename exceeds the maximum length
63	TOO MANY WATCHES	the maximum number of watches (8) has been exceeded
64	TOO MANY BREAKPOINTS	the maximum number of breakpoints (16) has been exceeded
65	RORG REQUIRES ABSOLUTE ORIGIN	.RORG was used without a preceding absolute .ORG
66	UNCLOSED .IF	an .IF block was not closed with a matching .ENDIF
67	UNCLOSED .MAC OR .REP	a .MAC or .REP block was not closed with .ENDMAC/.ENDREP
68	CANNOT ASSEMBLE LOG	an attempt was made to assemble the LOG buffer
69	DIVIDE BY ZERO	an expression attempted a division by zero
70	DUPLICATE BLOCK	a LINK file declares its MEMORY or SEGMENTS block more than once
71	UNKNOWN KEY	a LINK file uses an unrecognized property key in a memory section or segment definition
72	NO SEGMENTS DEFINED	no segments were defined for the linker to place
73	TOO MANY NESTED IFS	the maximum nesting depth of 8 .IF/.IFDEF blocks has been exceeded
74	TOO MANY IFDEFS	the maximum of 255 .IFDEF directives in one assembly has been exceeded
75	IFDEF PASS MISMATCH	pass 2 encountered an .IFDEF with no corresponding result recorded during pass 1
76	MISSING REQUIRED KEY	a LINK file definition omits a required property (START/END for a memory section, LOAD for a segment)
77	TOO MANY OBJECTS	more object files were given to the linker than it can link at once (16)
78	DUPLICATE NAME	a LINK file declares two memory sections, or two segments, with the same name
79	SEGMENT OUT OF RANGE	a segment’s placement runs past the top of the address space ($FFFF)
80	NON INTEGRAL VALUE	a floating point value was used where only an integer is allowed
81	INVALID ALIGNMENT	a LINK file segment’s ALIGN is invalid or outside the range 1–65535
82	WATCH ALREADY EXISTS	the monitor already has a watch for the same address or exact range; remove it before adding another mode