-rw-r--r-- 1836 libmceliece-20241009/crypto_kem/8192128/avx/util.h raw
/*
  This file is for loading/storing data in a little-endian fashion
*/
// 20240805 djb: more use of cryptoint
// 20240508 djb: include vec128_gf.h

#ifndef UTIL_H
#define UTIL_H

#include "vec128_gf.h"
#include "params.h"

#include <stdint.h>
#include "crypto_int64.h"

static inline void store_gf(unsigned char *dest, uint16_t a)
{
	dest[0] = a & 0xFF;
	dest[1] = a >> 8;
}

static inline uint16_t load_gf(const unsigned char *src)
{
	uint16_t a;

	a = src[1];
	a <<= 8;
	a |= src[0];

	return a & GFMASK;
}

static inline uint32_t load4(const unsigned char *src)
{
	uint32_t a;

	a  = src[3]; a <<= 8; 
	a |= src[2]; a <<= 8;
	a |= src[1]; a <<= 8;
	a |= src[0];

	return a;
}

static inline void irr_load(vec128 * out, const unsigned char * in)
{
	int i, j;
	uint64_t v0 = 0, v1 = 0;
	uint16_t irr[ SYS_T ];

	for (i = 0; i < SYS_T; i++)
		irr[i] = load_gf(in + i*2);

	for (i = 0; i < GFBITS; i++)
	{
		for (j = 63; j >= 0; j--)
		{
			v0 <<= 1;
			v1 <<= 1;
			v0 |= crypto_int64_bitmod_01(irr[j], i);
			v1 |= crypto_int64_bitmod_01(irr[j+64], i);
		}

		out[i] = vec128_set2x(v0, v1);
	}
}

static inline void store8(unsigned char *out, uint64_t in)
{
	out[0] = (in >> 0x00) & 0xFF;
	out[1] = (in >> 0x08) & 0xFF;
	out[2] = (in >> 0x10) & 0xFF;
	out[3] = (in >> 0x18) & 0xFF;
	out[4] = (in >> 0x20) & 0xFF;
	out[5] = (in >> 0x28) & 0xFF;
	out[6] = (in >> 0x30) & 0xFF;
	out[7] = (in >> 0x38) & 0xFF;
}

static inline uint64_t load8(const unsigned char * in)
{
	int i;
	uint64_t ret = in[7];

	for (i = 6; i >= 0; i--)
	{
		ret <<= 8;
		ret |= in[i];
	}

	return ret;
}

static inline vec128 load16(const unsigned char * in)
{
	return vec128_set2x( load8(in), load8(in+8) );
}

static inline void store16(unsigned char * out, vec128 in)
{
	store8(out+0, vec128_extract(in, 0));
	store8(out+8, vec128_extract(in, 1));
}

#endif