Computers as Components, 2nd Edition

5.3 Assembly, Linking, and Loading 225

Assemblers allow labels to be added to the symbol table without occupying

space in the program memory. A typical name of this pseudo-op is EQU for equate.

For example, in the code

ADD r0,r1,r2

FOO EQU 5

BAZ SUB r3,r4,#FOO

the EQU pseudo-op adds a label named FOO with the value 5 to the symbol table.

The value of the BAZ label is the same as if the EQU pseudo-op were not present,

since EQU does not advance the PLC. The new label is used in the subsequent SUB

instruction as the name for a constant. EQUs can be used to define symbolic values

to help make the assembly code more structured.

TheARM assembler supports one ...