VFRCZPD instruction (XOP)

Forms

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

Instruction	Encoding	Requires
`VFRCZPD xmm, m128` VFRCZPD_XMMdq_MEMdq	`XOP.128.NP.09.W0 81 /r`	XOP
`VFRCZPD xmm, xmm` VFRCZPD_XMMdq_XMMdq	`XOP.128.NP.09.W0 81 /r`	XOP
`VFRCZPD ymm, m256` VFRCZPD_YMMqq_MEMqq	`XOP.256.NP.09.W0 81 /r`	XOP
`VFRCZPD ymm, ymm` VFRCZPD_YMMqq_YMMqq	`XOP.256.NP.09.W0 81 /r`	XOP

Data flow

Where the elements of the sources go, element 0 on the right; results that depend on a control value are drawn for an example. How to read.

Element-wise: each double of the result comes from the double in the same place in each source.

Every double works alike: 2 and 4 doubles in the xmm and ymm forms.

Result double i comes from double i of xmm2. Result doubles 1 to 0: r1, r0.

Operation

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

r = cpuid_leaf(0x80000001, 0)[2]
if not r >> 11 & 1:
    fault(UD)                    # CPUID: no XOP
for i in range(VL // 64):
    a = src2.f64[i]
    t = round(a, 0b1011)         # toward zero, no PE
    ymm1.f64[i] = sub(a, t)      # exact
# a whole number gives -0 where MXCSR.RC
# rounds down, else +0; a denormal is its
# own fraction (DE), a zero of its sign
# with FTZ (UE, PE); an infinity raises IE
# and gives the QNaN indefinite
# ymm1 is zeroed from bit VL up

Run on AMD Zen 5 (EPYC 9645): 4 cases. Its cases ran where CPUID reported no XOP, and every one raised an exception.

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
`VFRCZPD xmm, xmm/m128` `VFRCZPD ymm, ymm/m256`
`xmm, ymm`	explicit	write
`xmm/m128, ymm/m256`	explicit	read

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: follows MXCSR

Intrinsics

The C intrinsics of Clang 23.1.2 that compile to VFRCZPD, each with the form it compiles to and the Clang options it needs. The forms come from compiling every intrinsic and decoding the result with Intel XED; all intrinsics A–Z explains the method.

Intrinsic	Compiles to
`_mm_frcz_pd` `__m128d _mm_frcz_pd(__m128d __A)`	`VFRCZPD xmm, xmm` XOP.128 -mxop
`_mm256_frcz_pd` `__m256d _mm256_frcz_pd(__m256d __A)`	`VFRCZPD ymm, ymm` XOP.256 -mxop

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
`XOP` XOP	XOP `CPUID.80000001H:ECX[11]` XOP	Bulldozer, Piledriver

More XOP instructions

All 55 XOP instructions