CS 2734 Computer Organization II

In this lecture we will start to examine the decoding part of the instruction cycle.

• Sparc instructions are encoded in four possible forms:

  Opcode	Instruction Group
  00	Branch instructions
  01	call instruction
  10	Format three instructions
  11	Format three instructions

• We will be referring to Paul during this lecture, so please bring your book.

• Register encoding:

  Registers	Encoding (5 bit)
  %g0 through %g7	0 through 7
  %o0 through %o7	8 through 15
  %l0 through %l7	16 through 23
  %i0 through %i7	24 through 31

• Format three encoding:

  Opcode	Operation
  000000	add
  000001	and
  000010	or
  000011	xor
  000100	sub
  000101	andn
  000110	orn
  000111	xnor

  • The x version has bit 3 set.
  • The cc version has bit 4 set.
  • The xcc version has bits 3 and 4 set.

• Encoding of call.

• Encoding of branch instructions.

• Encoding of format two instructions (sethi and or).