val lengthByteCount = (lengthBitCount + 7) / 8
      sink.writeByte(0b1000_0000 or lengthByteCount)
      for (shift in (lengthByteCount - 1) * 8 downTo 0 step 8) {
        sink.writeByte((length shr shift).toInt())
      }
    }

    // Write the payload.
    sink.writeAll(content)
  }

  /**
   * Execute [block] with a new namespace for type hints. Type hints from the enclosing type are no

	MOVL	AX, DI
	MOVL	DX, SI

	// DI = nano/100/1e9 = nano/1e11 = sec/100, DX = SI = nano/100%1e9
	// split DX into seconds and nanoseconds by div 1e7 magic multiply.
	MOVL	DX, AX
	MOVL	$1801439851, CX
	MULL	CX
	SHRL	$22, DX
	MOVL	DX, BX
	IMULL	$10000000, DX
	MOVL	SI, CX
	SUBL	DX, CX

	// DI = sec/100 (still)
	// BX = (nano/100%1e9)/1e7 = (nano/1e9)%100 = sec%100
	// CX = (nano/100%1e9)%1e7 = (nano%1e9)/100 = nsec/100

const CacheLinePadSize = 128

func doinit() {
	options = []option{
		{Name: "aes", Feature: &ARM64.HasAES},
		{Name: "pmull", Feature: &ARM64.HasPMULL},
		{Name: "sha1", Feature: &ARM64.HasSHA1},
		{Name: "sha2", Feature: &ARM64.HasSHA2},
		{Name: "sha512", Feature: &ARM64.HasSHA512},
		{Name: "crc32", Feature: &ARM64.HasCRC32},
		{Name: "atomics", Feature: &ARM64.HasATOMICS},
		{Name: "cpuid", Feature: &ARM64.HasCPUID},

		return true
	}
	// match: (SHRB _ (MOVQconst [c]))
	// cond: c&31 >= 8
	// result: (MOVLconst [0])
	for {
		if v_1.Op != OpAMD64MOVQconst {
			break
		}
		c := auxIntToInt64(v_1.AuxInt)
		if !(c&31 >= 8) {
			break
		}
		v.reset(OpAMD64MOVLconst)
		v.AuxInt = int32ToAuxInt(0)
		return true
	}
	// match: (SHRB _ (MOVLconst [c]))
	// cond: c&31 >= 8

	token.REM_ASSIGN:     token.REM,
	token.AND_ASSIGN:     token.AND,
	token.OR_ASSIGN:      token.OR,
	token.XOR_ASSIGN:     token.XOR,
	token.SHL_ASSIGN:     token.SHL,
	token.SHR_ASSIGN:     token.SHR,
	token.AND_NOT_ASSIGN: token.AND_NOT,
}

func TestZeroTok(t *testing.T) {
	// zero value for token.Token must be token.ILLEGAL
	var zero token.Token
	if token.ILLEGAL != zero {

	MOVOU	X0, -96(DI)(BX*1)
	MOVOU	X0, -80(DI)(BX*1)
	MOVOU	X0, -64(DI)(BX*1)
	MOVOU	X0, -48(DI)(BX*1)
	MOVOU	X0, -32(DI)(BX*1)
	MOVOU	X0, -16(DI)(BX*1)
	RET
nosse2:
	MOVL	BX, CX
	SHRL	$2, CX
	REP
	STOSL
	ANDL	$3, BX
	JNE	tail

	_ = x[Gtr-11]
	_ = x[Geq-12]
	_ = x[Add-13]
	_ = x[Sub-14]
	_ = x[Or-15]
	_ = x[Xor-16]
	_ = x[Mul-17]
	_ = x[Div-18]
	_ = x[Rem-19]
	_ = x[And-20]
	_ = x[AndNot-21]
	_ = x[Shl-22]
	_ = x[Shr-23]
}

const _Operator_name = ":!<-~||&&==!=<<=>>=+-|^*/%&&^<<>>"

var _Operator_index = [...]uint8{0, 1, 2, 4, 5, 7, 9, 11, 13, 14, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 31, 33}

		{Name: "jscvt", Feature: &ARM64.HasJSCVT},
		{Name: "lrcpc", Feature: &ARM64.HasLRCPC},
		{Name: "pmull", Feature: &ARM64.HasPMULL},
		{Name: "sha1", Feature: &ARM64.HasSHA1},
		{Name: "sha2", Feature: &ARM64.HasSHA2},
		{Name: "sha3", Feature: &ARM64.HasSHA3},
		{Name: "sha512", Feature: &ARM64.HasSHA512},
		{Name: "sm3", Feature: &ARM64.HasSM3},
		{Name: "sm4", Feature: &ARM64.HasSM4},

// output of arbitrary length. SHAKE256, with an output length of at least
// 64 bytes, provides 256-bit security against all attacks.  The Keccak team
// recommends it for most applications upgrading from SHA2-512. (NIST chose a
// much stronger, but much slower, sponge instance for SHA3-512.)
//
// The SHA-3 functions are "drop-in" replacements for the SHA-2 functions.

endofpage:
	MOVOU	-16(SI)(BX*1), X1	// Load data into the high end of X1.
	PCMPEQB	X0, X1	// Compare target byte with each byte in data.
	PMOVMSKB X1, DX	// Move result bits to integer register.
	MOVL	BX, CX
	SHLL	CX, DX
	SHRL	$16, DX	// Shift desired bits down to bottom of register.
	BSFL	DX, DX	// Find first set bit.
	JZ	failure	// No set bit, failure.
	MOVQ	DX, (R8)
	RET

avx2:
#ifndef hasAVX2