4Assembler Directives and Pseudo-Operations
Assembler directives and pseudo-operations allow you to take special programming actions during the assembly process. The directive and pseudo-operation names begin with a period (.) to distinguish them from machine instruction opcodes or extended opcodes.
Introduction
Table 4-1 lists the Assembler directives. Table 4-2 on page 55 lists the pseudo-operations. The directives include those that establish the procedure-calling convention, declare common, and define spaces and subspaces. The pseudo-operations reserve and initialize data areas.
The remainder of this chapter lists the Assembler directives and pseudo-operations in alphabetic order. Several of the descriptions include sample assembly code sequences. You can enter these short code sequences, assemble them using the -loption of the as command, then inspect the offsets and field values to see how that particular directive controls the assembly environment.
This chapter also includes Table 4-3 on page 116 under “Programming Aids” on page 116, which lists the predefined directives that establish standard spaces and subspaces.
Table 4-1 | Assembler Directives |
| | |
| Directive | Function |
| | |
| .ALIGN | Forces location counter to the next largest |
| | multiple of the supplied alignment value. |
| | |
| .ALLOW | Used with a .LEVEL directive, it temporarily |
| | allows the use of features in the architecture |
| | specified in the .LEVEL directive. |
| | |
| .CALL | Specifies that the next statement is a procedure |
| | call. |
| | |