XSETBV instruction (XSAVE)

Forms

Every encoding of XSETBV that Intel XED knows, one row per XED instruction form (iform). How to read the notation.

Instruction	Encoding	Requires
`XSETBV` XSETBV	`NP 0F 01 D1`	XSAVE + OSXSAVE

Operation

What the forms do, in pseudocode that our tests run against results recorded on real processors. How to read.

if CPL > 0 or ecx != 0:              # XCR0 is the only one it writes
    fault(GP, 0)
v = edx << 32 | eax
r = cpuid_leaf(0xD, 0)               # the user components there are
if v & ~(r[3] << 32 | r[0]):
    fault(GP, 0)
if not v & 1 or v & 6 == 4:          # x87 always; AVX only with SSE
    fault(GP, 0)
if v & 0x18 not in (0, 0x18):        # MPX's two together
    fault(GP, 0)
if v & 0xE0 and v & 0xE6 != 0xE6:    # AVX-512's three together, with
    fault(GP, 0)                     # AVX and SSE
if v >> 17 & 1 != v >> 18 & 1:       # AMX's two together
    fault(GP, 0)
xcr0 = v

Not run on a processor: XSETBV runs at CPL 0 only.

Operands

What each form reads and writes, as Intel XED records it: the operands of its syntax, in order, and the implicit ones that the syntax does not name. How to read.

Operand	Kind	Action
`XSETBV`
`ECX`	implicit	read
`EDX`	implicit	read
`EAX`	implicit	read
`XCR0`	implicit	write

Flags

None: XED records no flag that the forms test or change.

Attributes

What else XED records about the forms. How to read.

All forms: privileged: CPL 0 only; may abort a TSX transaction

CPUID and processors

Each form belongs to an XED ISA set. A form can be used when the processor reports every CPUID bit of one of its ISA set's alternatives.

CPUID requirements and processors of the XED ISA sets above. Alternatives are separated by “or”; processors follow XED’s chip model, whose AMD processors end with Zen 2, and the CPU data of this site for Zen 3 to Zen 6.

ISA set	CPUID	Processors
`XSAVE` XSAVE	XSAVE + OSXSAVE `CPUID.01H:ECX[26]` XSAVE `CPUID.01H:ECX[27]` OSXSAVE	Sandy Bridge, Ivy Bridge, Haswell, Broadwell, Skylake, Comet Lake, Cannon Lake, Ice Lake (client), Tiger Lake, Alder Lake, Arrow Lake, Panther Lake, Nova Lake, Skylake-SP, Cascade Lake, Cooper Lake, Ice Lake (server), Sapphire Rapids, Emerald Rapids, Granite Rapids, Diamond Rapids, Goldmont, Goldmont Plus, Tremont, Snow Ridge, Lakefield, Sierra Forest, Clearwater Forest, Knights Landing, Knights Mill, Bulldozer, Piledriver, Zen, Zen+, Zen 2, Zen 3, Zen 4, Zen 5, Zen 6

XSETBV