Addressing

In the following:

• five is absolute symbol (e.g., five EQU 5)
• label is relative symbol (e.g., label FIX)

Immediate addressing

• precedence order: signed absolute, pc, base
• absolute (direct): signed 12-bit operand
  • LDA #5
  • LDA #-42
  • LDA #five
• pc-relative: signed 12-bit displacement
  • LDA #label
• base-relative: unsigned 12-bit displacement
  • LDA #label
• absolute extended: unsigned 20-bit operand
  • +LDA #5
  • +LDA #five
  • +LDA #label

Indirect addressing

• precedence order: pc, base, absolute
• absolute (direct): unsigned 12-bit address
  • LDA @5
  • LDA @five
• pc-relative: signed 12-bit displacement
  • LDA #label
• base-relative: unsigned 12-bit displacement
  • LDA #label
• absolute extended: unsigned 20-bit address
  • +LDA @5
  • +LDA @five
  • +LDA @label

Simple addressing

• precedence order: pc, base, absolute, sic absolute
• absolute (direct): unsigned 12-bit address
  • LDA 5
  • LDA five
• pc-relative: signed 12-bit displacement
  • LDA #label
• base-relative: unsigned 12-bit displacement
  • LDA #label
• sic absolute: unsigned 15 bit address
  • LDA 5
  • LDA five
  • LDA label
  • program becomes unrelocatable
• absolute extended: unsigned 20-bit address
  • +LDA 5
  • +LDA label
• all modes can be combined with indexed addressing