#undef z1sqr
#undef h
#undef r
#undef hsqr
#undef rsqr
#undef hcub
#undef rptr
#undef sel_save
#undef zero_save

// p256IsZero returns 1 in AX if [acc4..acc7] represents zero and zero
// otherwise. It writes to [acc4..acc7], t0 and t1.
TEXT p256IsZero(SB),NOSPLIT,$0
	// AX contains a flag that is set if the input is zero.
	XORQ AX, AX
	MOVQ $1, t1

	// Check whether [acc4..acc7] are all zero.