# Assembly language ## Syntax ADD $01 ; comments follow a `;` ADD $FF ; this is direct addressing ADD ($CC) ; this is indirect addressing END ; END and NOP don't require operands ; (the assembler will fill in a default value of 0) @subroutine ; create a label ADD $01 ; (it must be on the line before the code it names) ADD $02 JMP @subroutine ; use a label as operand ; the label will be replaced with ; the address of the label #foo $FF ; define a constant ; (must be defined before it is referenced) ADD #foo ; use a constant as an operand LDA * ; `*` is a special label referencing the memory address ; where the current line will be stored after assembly - Prefix hexadecimal numbers with `$` (or `0x`) - Prefix binary numbers with `0b` - Whitespace is ignored