/*
  +----------------------------------------------------------------------+
  | Copyright © The PHP Group and Contributors.                          |
  +----------------------------------------------------------------------+
  | This source file is subject to the Modified BSD License that is      |
  | bundled with this package in the file LICENSE, and is available      |
  | through the World Wide Web at <https://www.php.net/license/>.        |
  |                                                                      |
  | SPDX-License-Identifier: BSD-3-Clause                                |
  +----------------------------------------------------------------------+
  | Author: Frank Du <frank.du@intel.com>                                |
  +----------------------------------------------------------------------+
  | Compute the crc32 of the buffer. Based on:                           |
  | "Fast CRC Computation for Generic Polynomials Using PCLMULQDQ"       |
  |  V. Gopal, E. Ozturk, et al., 2009, http://intel.ly/2ySEwL0          |
*/

#include "crc32_x86.h"

#if defined(ZEND_INTRIN_SSE4_2_PCLMUL_NATIVE) || defined(ZEND_INTRIN_SSE4_2_PCLMUL_RESOLVER)
# include <nmmintrin.h>
# include <wmmintrin.h>
#endif

#ifdef ZEND_INTRIN_SSE4_2_PCLMUL_RESOLVER
# include "Zend/zend_cpuinfo.h"
#endif

#if defined(ZEND_INTRIN_SSE4_2_PCLMUL_NATIVE) || defined(ZEND_INTRIN_SSE4_2_PCLMUL_RESOLVER)

typedef struct _crc32_pclmul_bit_consts {
	uint64_t k1k2[2];
	uint64_t k3k4[2];
	uint64_t k5k6[2];
	uint64_t uPx[2];
} crc32_pclmul_consts;

static const crc32_pclmul_consts crc32_pclmul_consts_maps[X86_CRC32_MAX] = {
	{ /* X86_CRC32, polynomial: 0x04C11DB7 */
		{0x00e6228b11, 0x008833794c}, /* endianness swap */
		{0x00e8a45605, 0x00c5b9cd4c}, /* endianness swap */
		{0x00490d678d, 0x00f200aa66}, /* endianness swap */
		{0x0104d101df, 0x0104c11db7}
	},
	{ /* X86_CRC32B, polynomial: 0x04C11DB7 with reversed ordering */
		{0x0154442bd4, 0x01c6e41596},
		{0x01751997d0, 0x00ccaa009e},
		{0x0163cd6124, 0x01db710640},
		{0x01f7011641, 0x01db710641},
	},
	{ /* X86_CRC32C, polynomial: 0x1EDC6F41 with reversed ordering */
		{0x00740eef02, 0x009e4addf8},
		{0x00f20c0dfe, 0x014cd00bd6},
		{0x00dd45aab8, 0x0000000000},
		{0x00dea713f1, 0x0105ec76f0}
	}
};

static uint8_t pclmul_shuf_mask_table[16] = {
	0x0f, 0x0e, 0x0d, 0x0c, 0x0b, 0x0a, 0x09, 0x08,
	0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00,
};

/* Folding of 128-bit data chunks */
#define CRC32_FOLDING_BLOCK_SIZE (16)

/* PCLMUL version of non-reflected crc32 */
ZEND_INTRIN_SSE4_2_PCLMUL_FUNC_DECL(size_t crc32_pclmul_batch(uint32_t *crc, const unsigned char *p, size_t nr, const crc32_pclmul_consts *consts));
size_t crc32_pclmul_batch(uint32_t *crc, const unsigned char *p, size_t nr, const crc32_pclmul_consts *consts)
{
	size_t nr_in = nr;
	__m128i x0, x1, x2, k, shuf_mask;

	if (nr < CRC32_FOLDING_BLOCK_SIZE) {
		return 0;
	}

	shuf_mask = _mm_loadu_si128((__m128i *)(pclmul_shuf_mask_table));
	x0 = _mm_cvtsi32_si128(*crc);
	x1 = _mm_loadu_si128((__m128i *)(p + 0x00));
	x0 = _mm_slli_si128(x0, 12);
	x1 = _mm_shuffle_epi8(x1, shuf_mask); /* endianness swap */
	x0 = _mm_xor_si128(x1, x0);
	p += CRC32_FOLDING_BLOCK_SIZE;
	nr -= CRC32_FOLDING_BLOCK_SIZE;

	if (nr >= (CRC32_FOLDING_BLOCK_SIZE * 3)) {
		__m128i x3, x4;

		x1 = _mm_loadu_si128((__m128i *)(p + 0x00));
		x1 = _mm_shuffle_epi8(x1, shuf_mask); /* endianness swap */
		x2 = _mm_loadu_si128((__m128i *)(p + 0x10));
		x2 = _mm_shuffle_epi8(x2, shuf_mask); /* endianness swap */
		x3 = _mm_loadu_si128((__m128i *)(p + 0x20));
		x3 = _mm_shuffle_epi8(x3, shuf_mask); /* endianness swap */
		p += CRC32_FOLDING_BLOCK_SIZE * 3;
		nr -= CRC32_FOLDING_BLOCK_SIZE * 3;

		k = _mm_loadu_si128((__m128i *)consts->k1k2);
		/* parallel folding by 4 */
		while (nr >= (CRC32_FOLDING_BLOCK_SIZE * 4)) {
			__m128i x5, x6, x7, x8, x9, x10, x11;
			x4 = _mm_clmulepi64_si128(x0, k, 0x00);
			x5 = _mm_clmulepi64_si128(x1, k, 0x00);
			x6 = _mm_clmulepi64_si128(x2, k, 0x00);
			x7 = _mm_clmulepi64_si128(x3, k, 0x00);
			x0 = _mm_clmulepi64_si128(x0, k, 0x11);
			x1 = _mm_clmulepi64_si128(x1, k, 0x11);
			x2 = _mm_clmulepi64_si128(x2, k, 0x11);
			x3 = _mm_clmulepi64_si128(x3, k, 0x11);
			x8 = _mm_loadu_si128((__m128i *)(p + 0x00));
			x8 = _mm_shuffle_epi8(x8, shuf_mask); /* endianness swap */
			x9 = _mm_loadu_si128((__m128i *)(p + 0x10));
			x9 = _mm_shuffle_epi8(x9, shuf_mask); /* endianness swap */
			x10 = _mm_loadu_si128((__m128i *)(p + 0x20));
			x10 = _mm_shuffle_epi8(x10, shuf_mask); /* endianness swap */
			x11 = _mm_loadu_si128((__m128i *)(p + 0x30));
			x11 = _mm_shuffle_epi8(x11, shuf_mask); /* endianness swap */
			x0 = _mm_xor_si128(x0, x4);
			x1 = _mm_xor_si128(x1, x5);
			x2 = _mm_xor_si128(x2, x6);
			x3 = _mm_xor_si128(x3, x7);
			x0 = _mm_xor_si128(x0, x8);
			x1 = _mm_xor_si128(x1, x9);
			x2 = _mm_xor_si128(x2, x10);
			x3 = _mm_xor_si128(x3, x11);

			p += CRC32_FOLDING_BLOCK_SIZE * 4;
			nr -= CRC32_FOLDING_BLOCK_SIZE * 4;
		}

		k = _mm_loadu_si128((__m128i *)consts->k3k4);
		/* fold 4 to 1, [x1, x2, x3] -> x0 */
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x1);
		x0 = _mm_xor_si128(x0, x4);
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x2);
		x0 = _mm_xor_si128(x0, x4);
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x3);
		x0 = _mm_xor_si128(x0, x4);
	}

	k = _mm_loadu_si128((__m128i *)consts->k3k4);
	/* folding by 1 */
	while (nr >= CRC32_FOLDING_BLOCK_SIZE) {
		/* load next to x2, fold to x0, x1 */
		x2 = _mm_loadu_si128((__m128i *)(p + 0x00));
		x2 = _mm_shuffle_epi8(x2, shuf_mask); /* endianness swap */
		x1 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x2);
		x0 = _mm_xor_si128(x0, x1);
		p += CRC32_FOLDING_BLOCK_SIZE;
		nr -= CRC32_FOLDING_BLOCK_SIZE;
	}

	/* reduce 128-bits(final fold) to 96-bits */
	k = _mm_loadu_si128((__m128i*)consts->k5k6);
	x1 = _mm_clmulepi64_si128(x0, k, 0x11);
	x0 = _mm_slli_si128(x0, 8);
	x0 = _mm_srli_si128(x0, 4);
	x0 = _mm_xor_si128(x0, x1);
	/* reduce 96-bits to 64-bits */
	x1 = _mm_clmulepi64_si128(x0, k, 0x01);
	x0 = _mm_xor_si128(x0, x1);

	/* barrett reduction */
	k = _mm_loadu_si128((__m128i*)consts->uPx);
	x1 = _mm_move_epi64(x0);
	x1 = _mm_srli_si128(x1, 4);
	x1 = _mm_clmulepi64_si128(x1, k, 0x00);
	x1 = _mm_srli_si128(x1, 4);
	x1 = _mm_clmulepi64_si128(x1, k, 0x10);
	x0 = _mm_xor_si128(x1, x0);
	*crc =  _mm_extract_epi32(x0, 0);
	return (nr_in - nr); /* the nr processed */
}

/* PCLMUL version of reflected crc32 */
ZEND_INTRIN_SSE4_2_PCLMUL_FUNC_DECL(size_t crc32_pclmul_reflected_batch(uint32_t *crc, const unsigned char *p, size_t nr, const crc32_pclmul_consts *consts));
size_t crc32_pclmul_reflected_batch(uint32_t *crc, const unsigned char *p, size_t nr, const crc32_pclmul_consts *consts)
{
	size_t nr_in = nr;
	__m128i x0, x1, x2, k;

	if (nr < CRC32_FOLDING_BLOCK_SIZE) {
		return 0;
	}

	x0 = _mm_loadu_si128((__m128i *)(p + 0x00));
	x0 = _mm_xor_si128(x0, _mm_cvtsi32_si128(*crc));
	p += CRC32_FOLDING_BLOCK_SIZE;
	nr -= CRC32_FOLDING_BLOCK_SIZE;
	if (nr >= (CRC32_FOLDING_BLOCK_SIZE * 3)) {
		__m128i x3, x4;

		x1 = _mm_loadu_si128((__m128i *)(p + 0x00));
		x2 = _mm_loadu_si128((__m128i *)(p + 0x10));
		x3 = _mm_loadu_si128((__m128i *)(p + 0x20));
		p += CRC32_FOLDING_BLOCK_SIZE * 3;
		nr -= CRC32_FOLDING_BLOCK_SIZE * 3;

		k = _mm_loadu_si128((__m128i *)consts->k1k2);
		/* parallel folding by 4 */
		while (nr >= (CRC32_FOLDING_BLOCK_SIZE * 4)) {
			__m128i x5, x6, x7, x8, x9, x10, x11;
			x4 = _mm_clmulepi64_si128(x0, k, 0x00);
			x5 = _mm_clmulepi64_si128(x1, k, 0x00);
			x6 = _mm_clmulepi64_si128(x2, k, 0x00);
			x7 = _mm_clmulepi64_si128(x3, k, 0x00);
			x0 = _mm_clmulepi64_si128(x0, k, 0x11);
			x1 = _mm_clmulepi64_si128(x1, k, 0x11);
			x2 = _mm_clmulepi64_si128(x2, k, 0x11);
			x3 = _mm_clmulepi64_si128(x3, k, 0x11);
			x8 = _mm_loadu_si128((__m128i *)(p + 0x00));
			x9 = _mm_loadu_si128((__m128i *)(p + 0x10));
			x10 = _mm_loadu_si128((__m128i *)(p + 0x20));
			x11 = _mm_loadu_si128((__m128i *)(p + 0x30));
			x0 = _mm_xor_si128(x0, x4);
			x1 = _mm_xor_si128(x1, x5);
			x2 = _mm_xor_si128(x2, x6);
			x3 = _mm_xor_si128(x3, x7);
			x0 = _mm_xor_si128(x0, x8);
			x1 = _mm_xor_si128(x1, x9);
			x2 = _mm_xor_si128(x2, x10);
			x3 = _mm_xor_si128(x3, x11);

			p += CRC32_FOLDING_BLOCK_SIZE * 4;
			nr -= CRC32_FOLDING_BLOCK_SIZE * 4;
		}

		k = _mm_loadu_si128((__m128i *)consts->k3k4);
		/* fold 4 to 1, [x1, x2, x3] -> x0 */
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x1);
		x0 = _mm_xor_si128(x0, x4);
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x2);
		x0 = _mm_xor_si128(x0, x4);
		x4 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x3);
		x0 = _mm_xor_si128(x0, x4);
	}

	k = _mm_loadu_si128((__m128i *)consts->k3k4);
	/* folding by 1 */
	while (nr >= CRC32_FOLDING_BLOCK_SIZE) {
		/* load next to x2, fold to x0, x1 */
		x2 = _mm_loadu_si128((__m128i *)(p + 0x00));
		x1 = _mm_clmulepi64_si128(x0, k, 0x00);
		x0 = _mm_clmulepi64_si128(x0, k, 0x11);
		x0 = _mm_xor_si128(x0, x2);
		x0 = _mm_xor_si128(x0, x1);
		p += CRC32_FOLDING_BLOCK_SIZE;
		nr -= CRC32_FOLDING_BLOCK_SIZE;
	}

	/* reduce 128-bits(final fold) to 96-bits */
	x1 = _mm_clmulepi64_si128(x0, k, 0x10);
	x0 = _mm_srli_si128(x0, 8);
	x0 = _mm_xor_si128(x0, x1);
	/* reduce 96-bits to 64-bits */
	x1 = _mm_shuffle_epi32(x0, 0xfc);
	x0 = _mm_shuffle_epi32(x0, 0xf9);
	k = _mm_loadu_si128((__m128i*)consts->k5k6);
	x1 = _mm_clmulepi64_si128(x1, k, 0x00);
	x0 = _mm_xor_si128(x0, x1);

	/* barrett reduction */
	x1 = _mm_shuffle_epi32(x0, 0xf3);
	x0 = _mm_slli_si128(x0, 4);
	k = _mm_loadu_si128((__m128i*)consts->uPx);
	x1 = _mm_clmulepi64_si128(x1, k, 0x00);
	x1 = _mm_clmulepi64_si128(x1, k, 0x10);
	x0 = _mm_xor_si128(x1, x0);
	*crc =  _mm_extract_epi32(x0, 2);
	return (nr_in - nr); /* the nr processed */
}

# if defined(ZEND_INTRIN_SSE4_2_PCLMUL_NATIVE)
size_t crc32_x86_simd_update(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr)
# else /* ZEND_INTRIN_SSE4_2_PCLMUL_RESOLVER */
size_t crc32_sse42_pclmul_update(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr)
# endif
{
	if (type > X86_CRC32_MAX) {
		return 0;
	}
	const crc32_pclmul_consts *consts = &crc32_pclmul_consts_maps[type];

	switch (type) {
	case X86_CRC32:
		return crc32_pclmul_batch(crc, p, nr, consts);
	case X86_CRC32B:
	case X86_CRC32C:
		return crc32_pclmul_reflected_batch(crc, p, nr, consts);
	default:
		return 0;
	}
}
#endif

#ifdef ZEND_INTRIN_SSE4_2_PCLMUL_RESOLVER
static size_t crc32_x86_simd_update_default(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr)
{
	return 0;
}

# ifdef ZEND_INTRIN_SSE4_2_PCLMUL_FUNC_PROTO
size_t crc32_x86_simd_update(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr) __attribute__((ifunc("resolve_crc32_x86_simd_update")));

typedef size_t (*crc32_x86_simd_func_t)(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr);

ZEND_NO_SANITIZE_ADDRESS
ZEND_ATTRIBUTE_UNUSED /* clang mistakenly warns about this */
static crc32_x86_simd_func_t resolve_crc32_x86_simd_update(void) {
	if (zend_cpu_supports_sse42() && zend_cpu_supports_pclmul()) {
		return crc32_sse42_pclmul_update;
	}
	return crc32_x86_simd_update_default;
}
# else /* ZEND_INTRIN_SSE4_2_PCLMUL_FUNC_PTR */
static size_t (*crc32_x86_simd_ptr)(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr) = crc32_x86_simd_update_default;

size_t crc32_x86_simd_update(X86_CRC32_TYPE type, uint32_t *crc, const unsigned char *p, size_t nr) {
	return crc32_x86_simd_ptr(type, crc, p, nr);
}

/* {{{ PHP_MINIT_FUNCTION */
PHP_MINIT_FUNCTION(crc32_x86_intrin)
{
	if (zend_cpu_supports_sse42() && zend_cpu_supports_pclmul()) {
		crc32_x86_simd_ptr = crc32_sse42_pclmul_update;
	}
	return SUCCESS;
}
/* }}} */
# endif
#endif
