VAES AVX2 test

go.mod

module vaes-avx2-test

go 1.25.1

main.go

package main

import "fmt"

// VAESProbeYMM executes one VAESENC with YMM regs.
// It will SIGILL if VAES (256-bit) isn't supported by the CPU/OS.
func VAESProbeYMM()

func main() {
	// If the instruction is unsupported, the process will crash before this prints.
	VAESProbeYMM()
	fmt.Println("ok: VAES YMM instruction executed")
}

vaes_amd64.s

//go:build amd64

#include "textflag.h"

// VAESProbeYMM executes a single VAESENC on YMM registers.
// If the CPU/OS doesn't support VAES (256-bit), this will SIGILL.
TEXT ·VAESProbeYMM(SB), NOSPLIT, $0-0
    // Make sure upper lanes are in a known state.
    VZEROUPPER

    // Zero two YMM registers to use as state and round key.
    // (We use VXORPS just to create valid YMM values.)
    VXORPS  Y0, Y0, Y0
    VXORPS  Y1, Y1, Y1

    // Perform one AES encryption round:
    // Intel syntax would be: VAESENC ymm0, ymm0, ymm1
    // Go Plan 9 syntax is src1, src2, dst — so:
    // dst = AESENC(src2, src1)
    VAESENC Y1, Y0, Y0

    // Clean up upper lanes for friendliness with legacy code.
    VZEROUPPER
    RET