3 undefined symbols, 4 reserved symbols, 6 constants – Motorola HC12 User Manual

Page 147: Undefined symbols, Reserved symbols, Constants, Undefined symbol example

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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.