The Assembler and Loader

In the GAMA, assembler and loader are interleaved: in contrast to most assemblers for native machines which first produce a relocatable object file which is linked together with other object files by a linker and then loaded into memory for execution, the GAMA assembler and loader directly transform assembler code into executable machine code in memory.

In addition to the instructions defined via definstr, the GAMA assembler handles the following pseudo instructions:

• .proc marks the beginning of a procedure; it is mainly used to restrict the scope of local labels thus allowing different procedures to use the same local labels
• .end marks the end of a procedure; in addition to restricting the scope of local labels together with .proc, it adds the end address of a procedure to the information in the corresponding hash table entry (third cell) in order to allow the procedure to be removed from memory
• .dynamic declares the following global labels (the entry points for procedures) to be dynamic (see section 7.3)
• .static declares the following global labels to be static
• any symbol is taken as a global label
• any number or string is taken as a local label
• (.module ) declares all following global labels to be in module ; if this module does not yet exist, it is created
• (.import-from ) imports from module (qualified import)
• (.import-module ) imports all labels from module (unqualified import)

The following example shows the usage of some of these pseudo instructions and how the assembler and loader transform assembler code into executable machine code in memory.