-rw-r--r-- 1435 libmceliece-20240726/crypto_kem/8192128/vec/util.h raw
/*
This file is for loading/storing data in a little-endian fashion
*/
#ifndef UTIL_H
#define UTIL_H
#include "vec.h"
#include <stdint.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(vec out[][GFBITS], 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 |= (irr[j] >> i) & 1;
v1 |= (irr[j+64] >> i) & 1;
}
out[0][i] = v0;
out[1][i] = 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;
}
#endif