Motorola HC12 用户手册
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.
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:
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.
to bits 16–23 of a 24-bit value.
7.6 Constants
The assembler supports integer and ASCII string constants.