Chapter 3 Introduction to OperationBasic Operation of Assembler and Linker 253.3 Basic Operation of Assembler and LinkerThe Cross-Assembler uses a section address format, in which the start address for each section asdefined with the section directive corresponds to its start address when linked. This allows theprogrammer to freely change the order of linking files.The following explanation illustrates a simple example of only one section. In this example you willassemble and link two source files, program1.asm and program2.asm.These two files have related external references and external definitions, where the subroutine ofprogram2.asm is called from program1.asm. Therefore the final list files cannot be created just byassembling program1.asm. In this example, you will generate with the linker a map file and generatethe final list files.Create source filesFirst, create the source files. Using an editor, create the two programs shown below (program1.asm andprogram2.asm).The contents of program1.asm are as follows.program1.asm consists of a section called _CODE (attribute CODE, link type PUBLIC) and a sectioncalled _DATA (attribute DATA, link type PUBLIC).global data_set__CODE section CODE, PUBLIC, 1mainmov 0, A0mov 0xff, D0mov 0x80, D1jsr data_setbra main_DATA section DATA, PUBLIC, 4data1 ds 4end
