Motorola HC12 - Manual (Page 147)

Assembler Syntax
Constants
MCUez HC12 Assembler User’s Manual
MOTOROLA Assembler Syntax 147
7.5.3 Undefined Symbols
If a label is neither defined in the source file nor declared external using XREF
or XREFB, the assembler considers it to be undefined and generates an error.
codeSec: SECTION
entry:
NOP
BNE entry
NOP
JMP end
JMP label <- Undeclared user defined symbol : label
end: RTS
END
Figure 7-4. Undefined Symbol Example
7.5.4 Reserved Symbols
Reserved symbols cannot be used for user-defined symbols. Register names are
reserved identifiers. For the HC12 processor, these reserved identifiers are:
A,B,CCR,D,X,Y,SP,PC,PCR,TEMP1,TEMP2
Additionally, the keyword PAGE is also a reserved identifier. It is used to refer
to bits 16–23 of a 24-bit value.
7.6 Constants
The assembler supports integer and ASCII string constants.