//	https://learn.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-170
_4args:
	MOVQ	24(SI), R9
	MOVQ	R9, X3
_3args:
	MOVQ	16(SI), R8
	MOVQ	R8, X2
_2args:
	MOVQ	8(SI), DX
	MOVQ	DX, X1
_1args:
	MOVQ	0(SI), CX
	MOVQ	CX, X0
_0args:

	// Call stdcall function.
	CALL	AX

	ADDQ	$(const_maxArgs*8), SP

	// Return result.
	MOVQ	0(SP), CX
	MOVQ	8(SP), SP
	MOVQ	AX, libcall_r1(CX)

}

func newMACGeneric(key *[32]byte) macGeneric {
	m := macGeneric{}
	initialize(key, &m.macState)
	return m
}

// macState holds numbers in saturated 64-bit little-endian limbs. That is,
// the value of [x0, x1, x2] is x[0] + x[1] * 2⁶⁴ + x[2] * 2¹²⁸.
type macState struct {
	// h is the main accumulator. It is to be interpreted modulo 2¹³⁰ - 5, but
	// can grow larger during and after rounds. It must, however, remain below