2.1. Directives and Identifiers¶

Directives

Directives are instructions for the assembler about what to do with the information that comes after them. Directives always start with a . like: .word or .section. We can use directives to say things like “here is a word (32-bit pattern) to place into memory”:

.word   0xABCDABCD

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Identifiers

Identifiers are how we name lines of code. They do not become code, they are just labels we can use later on to refer to a particular piece of data or instruction. Identifiers always need to end with a : and follow normal rules for naming things in programming - no spaces or odd characters, first character must be alphabetical - like X: or milesPerHour: or input1:. The identifier may be on the same line as the thing it names or on the preceding line:

@This word of memory can be referred to as X
X: .word   0xABCDABCD

@This word of memory can be referred to as pattern
pattern:
.word   0x12345678

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