Panasonic PanaXSeries MN1030 Series, User Manual

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Chapter 3 Introduction to Operation
38 Conditional Assembly and Linking
3.5 Conditional Assembly and Linking
The Cross-Assembler provides many assembler directives. Assembler directives are not converted
directly to machine language, but are used to control how the assembler processes.
For example, during the development stage a programmer may want to include a special program only
for debugging. This program must be deleted when the product is complete. That can be accomplished
by editing the source file, but if that editing is spread throughout the program, mistakes will be easy to
make.
It is convenient to use assembler directives in such cases. The conditions for assembly are defined at
the start of the program, and programs to be assembled when the conditions are satisfied or not satisfied
are written in the source file.
Create source file
Using an editor, create the program program5.asm shown below.
The contents of program5.asm are as follows.
The operation of this program is meaningless. The program will be used instead to explain program
structure as it pertains to conditional assembly.The define DEBUG on the first line selects DEBUG as
a condition by defining the identifier DEBUG. In the assembly control block starting with #ifdef
DEBUG on line 13, the instructions between #ifdef to #else will be assembled if DEBUG has been
defined, and the instructions between #else to #endif will be assembled if DEBUG is undefined. In this
example DEBUG was defined on line 1, so the instructions in the defined block will be assembled.
This program also uses a macro control directive. Lines 4 to 8 are the macro definition. The macro's
name is dat_set, and it has two parameters (adr, dat).
#define DEBUG
*
dat_set macro adr, dat
mov adr, A0
mov dat, D0
mov D0, (A0)
endm
*
_CODE section CODE, PUBLIC,2
main DEBUG
#ifdef
dat_set data1, 0x11
#else
#endif dat_set data1, 0x22
_DATA section DATA, PUBLIC, 2
data1 dw 0
data2 dw 0
end