// Copyright (c) 2012- PPSSPP Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0 or later versions.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.

#include <arm_neon.h>
#include "GPU/Common/TextureDecoder.h"

#ifndef ARM
#error Should not be compiled on non-ARM.
#endif

static const u16 MEMORY_ALIGNED16(QuickTexHashInitial[8]) = {0x0001U, 0x0083U, 0x4309U, 0x4d9bU, 0xb651U, 0x4b73U, 0x9bd9U, 0xc00bU};

u32 QuickTexHashNEON(const void *checkp, u32 size) {
	u32 check = 0;
	__builtin_prefetch(checkp, 0, 0);

	if (((intptr_t)checkp & 0xf) == 0 && (size & 0x3f) == 0) {
		uint32x4_t cursor = vdupq_n_u32(0);
		uint32x4_t cursor2 = vld1q_u32((const u32 *)QuickTexHashInitial);
		uint32x4_t update = vdupq_n_u32(0x24552455U);

		const u32 *p = (const u32 *)checkp;
		for (u32 i = 0; i < size / 16; i += 4) {
			cursor = vmlaq_u32(cursor, vld1q_u32(&p[4 * 0]), cursor2);
			cursor = veorq_u32(cursor, vld1q_u32(&p[4 * 1]));
			cursor = vaddq_u32(cursor, vld1q_u32(&p[4 * 2]));
			cursor = veorq_u32(cursor, vmulq_u32(vld1q_u32(&p[4 * 3]), cursor2));
			cursor2 = vaddq_u32(cursor2, update);

			p += 4 * 4;
		}

		cursor = vaddq_u32(cursor, cursor2);
		check = vgetq_lane_u32(cursor, 0) + vgetq_lane_u32(cursor, 1) + vgetq_lane_u32(cursor, 2) + vgetq_lane_u32(cursor, 3);
	} else {
		const u32 size_u32 = size / 4;
		const u32 *p = (const u32 *)checkp;
		for (u32 i = 0; i < size_u32; i += 4) {
			check += p[i + 0];
			check ^= p[i + 1];
			check += p[i + 2];
			check ^= p[i + 3];
		}
	}

	return check;
}