System Call Directive (Syscall); Entering And Modifying Source Program - Motorola M68CPU32BUG User Manual

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4.2.4

System Call Directive (SYSCALL)

This directive aids the user in making the TRAP #15 calls to the system functions. The format for
this directive is:
SYSCALL <function name>
For example, the following two pieces of code produce identical results.
TRAP
DC.W
or
SYSCALL
The CPU32Bug input default is hexadecimal, while other assemblers default to decimal. When
programming a CPU32Bug assembler TRAP function it is best to use the SYSCALL directive
and let CPU32Bug make the conversion. Refer to Chapter 5 (SYSTEM CALLS), for a complete
listing of all the functions provided.

4.3 ENTERING AND MODIFYING SOURCE PROGRAM

User programs are entered into memory using the one-line assembler/disassembler. The program
is entered in assembly language statements on a line-by-line basis. The source code is not saved
as it is converted immediately upon entry into machine code. This imposes several restrictions on
the type of source line that can be entered.
Symbols and labels, other than the defined instruction mnemonics, are not allowed. The
assembler has no means of storing the associated values of the symbols and labels in look-up
tables. This forces the programmer to use memory addresses and to enter data directly rather than
use labels.
Also, editing is accomplished by retyping an entirely new source line. Add or delete lines by
moving a block of memory data to free up or delete the appropriate number of locations (refer to
the BM command).
M68CPU32BUG/D
EXAMPLES
DC.W
DC.W
DC.W
DC.W
DC.W
#$F
0
.INCHR
DESCRIPTION
1234 Decimal number
&AAFE Hexadecimal number
'AB' ASCII String
'TB'+1 Expression
'C' ASCII character is right justified
4-10
ASSEMBLER/DISASSEMBLER