Assembly (AVR) Cheat Sheet

• Assembler Directives
  • .set
  • .text
  • .data
• Registers
  • r0 → freely available register that can be used for temporary values
  • r1 → assume to always hold value of 0; must be cleared if used
  • Caller-saved: r18 → r27, r30 → r31
  • Callee-saved: r2 → r17, r28 → r29
  • X → r27:r26
  • Y → r29:r28
  • Z → r31:r30
• Jump Instructions
  • breq - branch if equal (signed and unsigned)
  • brne - branch if not equal (signed and unsigned)
  • brlt - branch if less than (signed)
  • brlo - branch if lower/branch if less than (unsigned)
  • brge - branch if greater than or equal (signed)
  • brsh - branch if greater than or equal/branch if same or higher (unsigned)
• Instructions (K and q represent constants)

  ldi Ra, K	lds Ra, address	sts address, Rs	clr Ra
  add Ra, Rb	adc Ra, Rb	adiw Ra, K	sub Ra, Rb
  subi Ra, K	sbiw Ra, K	inc Ra	dec Ra
  mul Ra, Rb	movw Ra, Rb	lsl Ra	lsr Ra
  push Ra	pop Ra	call address	mov Ra, Rb
  breq address	brne address	brge address	brlt address
  brlo address	brsh address	cp Ra, Rb	cpi Ra, K
  tst Ra	ld Ra, X / Y / Z	ld Ra, X+ / Y+ / Z+	ld Ra, -X, -Y, -Z
  ldd Ra, Y + q	ldd Ra, Z + q	nop	st X / Y / Z, Ra
  st X+ / Y+ / Z+, Ra	st -X / -Y / -Z, Ra	jmp	ret