Relocating Macro Assembler Reference This appendix gives a summary of the operation of the "Relocating Macro Assembler" (named c.asm as distributed with the C Compiler). This appendix and the example assembly source files supplied with the C compiler should provide the basic information on how to use the "Relocating Macro Assembler" to create relocatable-object format files (ROF). It is further assumed that you are familiar with the 6809 instruction set and mnemonics. See the Microware Relocating Assembler Manual for a more detailed description. The main function of this appendix is to enable the reader to understand the output produced by c.asm. The Relocating Macro Assembler allows programs to be compiled separately and then linked together, and it also allows macros to be defined within programs. Differences between the Relocating Macro Assembler (RMA) and the Microware Interactive Assembler (MIA):
RMA does not have an interactive mode. Only a disk file is allowed as input. RMA output is an ROF file. The ROF file must be processed by the linker to produce an executable OS9 memory module. The layout of the ROF file is described later. RMA has a number of new directives to control the placement of code and data in the executable module. Since RMA does not produce memory modules, the MIA directives "mod" and "emod" are not present. Instead, new directives PSECT and VSECT control the allocation of code and data areas by the linker. RMA has no equivalent to the MIA "setdp" directive. Data (and DP) allocation is handled by the linker.
Symbolic Names A symbolic name is valid if it consists of from one to nine uppercase or lowercase characters, decimal digits or the characters "$", "_", "." or "@". RMA does not fold lowercase letters to uppercase. The names "Hi.you" and "HI.YOU" are distinct names.
Label field If a symbolic name in the label field of a source statement is followed by a : (colon), the name will be known globally (by all modules linked together). If no colon appears, the name will be known only in the PSECT in which it was defined. PSECT will be described later.
Undefined names
Listing format
Section Location Counters
Section Directives
PSECT Directive
VSECT Directive
CSECT Directive
RZB statement
Comparison Between Assembly Programs for the Microware Interactive Assember and the Relocating Macro Assembler The following two program examples simply fork a BASIC09. The purpose of the examples are to show some of the differences in the new relocating assembler. The differences are apparent. * this program forks a basic09 ifp1 use ..../defs/os9defs.a endc
Macro Interactive Assembler Source ifp1 use defsfile prmsize equ *-prm siz equ
Introduction to Macros
Operations
Macro Definition
Nested Macro Calls
Labels
Additional Pseudo-Instructions