ed448goldilocks/src/arch_32/p448.h

/* Copyright (c) 2014 Cryptography Research, Inc.
 * Released under the MIT License.  See LICENSE.txt for license information.
 */
#ifndef __P448_H__
#define __P448_H__ 1

#include "word.h"

#include <stdint.h>
#include <assert.h>

typedef struct p448_t {
  uint32_t limb[16];
} __attribute__((aligned(32))) p448_t;

#ifdef __cplusplus
extern "C" {
#endif

static __inline__ void
p448_set_ui (
    p448_t *out,
    uint64_t x
) __attribute__((unused,always_inline));

static __inline__ void
p448_add (
    p448_t *out,
    const p448_t *a,
    const p448_t *b
) __attribute__((unused,always_inline));
             
static __inline__ void
p448_sub (
    p448_t *out,
    const p448_t *a,
    const p448_t *b
) __attribute__((unused,always_inline));
             
static __inline__ void
p448_neg (
    p448_t *out,
    const p448_t *a
) __attribute__((unused,always_inline));
            
static __inline__ void
p448_cond_neg (
    p448_t *a,
    mask_t doNegate
) __attribute__((unused,always_inline));

static __inline__ void
p448_addw (
    p448_t *a,
    uint32_t x
) __attribute__((unused,always_inline));
             
static __inline__ void
p448_subw (
    p448_t *a,
    uint32_t x
) __attribute__((unused,always_inline));
             
static __inline__ void
p448_copy (
    p448_t *out,
    const p448_t *a
) __attribute__((unused,always_inline));
             
static __inline__ void
p448_weak_reduce (
    p448_t *inout
) __attribute__((unused,always_inline));
             
void
p448_strong_reduce (
    p448_t *inout
);

mask_t
p448_is_zero (
    const p448_t *in
);
             
static __inline__ void
p448_bias (
    p448_t *inout,
    int amount
) __attribute__((unused,always_inline));

void
p448_mul (
    p448_t *__restrict__ out,
    const p448_t *a,
    const p448_t *b
);

void
p448_mulw (
    p448_t *__restrict__ out,
    const p448_t *a,
    uint64_t b
);

void
p448_sqr (
    p448_t *__restrict__ out,
    const p448_t *a
);

void
p448_serialize (
    uint8_t *serial,
    const struct p448_t *x
);

mask_t
p448_deserialize (
    p448_t *x,
    const uint8_t serial[56]
);

static inline mask_t
p448_eq (
    const struct p448_t *a,
    const struct p448_t *b
) __attribute__((always_inline,unused));

/* -------------- Inline functions begin here -------------- */

void
p448_set_ui (
    p448_t *out,
    uint64_t x
) {
    int i;
    out->limb[0] = x & ((1<<28)-1);
    out->limb[1] = x>>28;
    for (i=2; i<16; i++) {
      out->limb[i] = 0;
    }
}

void
p448_add (
    p448_t *out,
    const p448_t *a,
    const p448_t *b
) {
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
        ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] + ((const uint32xn_t*)b)[i];
    }
    /*
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
        out->limb[i] = a->limb[i] + b->limb[i];
    }
    */
}

void
p448_sub (
    p448_t *out,
    const p448_t *a,
    const p448_t *b
) {
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
        ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] - ((const uint32xn_t*)b)[i];
    }
    /*
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
        out->limb[i] = a->limb[i] - b->limb[i];
    }
    */
}

void
p448_neg (
    p448_t *out,
    const p448_t *a
) {
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
        ((uint32xn_t*)out)[i] = -((const uint32xn_t*)a)[i];
    }
    /*
    unsigned int i;
    for (i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
        out->limb[i] = -a->limb[i];
    }
    */
}

void
p448_cond_neg(
    p448_t *a,
    mask_t doNegate
) {
    unsigned int i;
    struct p448_t negated;
    big_register_t *aa = (big_register_t *)a;
    big_register_t *nn = (big_register_t*)&negated;
    big_register_t m = br_set_to_mask(doNegate);
    
    p448_neg(&negated, a);
    p448_bias(&negated, 2);
    
    for (i=0; i<sizeof(*a)/sizeof(*aa); i++) {
        aa[i] = (aa[i] & ~m) | (nn[i] & m);
    }
}

void
p448_addw (
    p448_t *a,
    uint32_t x
) {
  a->limb[0] += x;
}
             
void
p448_subw (
    p448_t *a,
    uint32_t x
) {
  a->limb[0] -= x;
}

void
p448_copy (
    p448_t *out,
    const p448_t *a
) {
  *out = *a;
}

void
p448_bias (
    p448_t *a,
    int amt
) {
    uint32_t co1 = ((1ull<<28)-1)*amt, co2 = co1-amt;
    uint32x4_t lo = {co1,co1,co1,co1}, hi = {co2,co1,co1,co1};
    uint32x4_t *aa = (uint32x4_t*) a;
    aa[0] += lo;
    aa[1] += lo;
    aa[2] += hi;
    aa[3] += lo;
}

void
p448_weak_reduce (
    p448_t *a
) {
    uint64_t mask = (1ull<<28) - 1;
    uint64_t tmp = a->limb[15] >> 28;
    int i;
    a->limb[8] += tmp;
    for (i=15; i>0; i--) {
        a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>28);
    }
    a->limb[0] = (a->limb[0] & mask) + tmp;
}

mask_t
p448_eq (
    const struct p448_t *a,
    const struct p448_t *b
) {
    struct p448_t ra, rb;
    p448_copy(&ra, a);
    p448_copy(&rb, b);
    p448_weak_reduce(&ra);
    p448_weak_reduce(&rb);
    p448_sub(&ra, &ra, &rb);
    p448_bias(&ra, 2);
    return p448_is_zero(&ra);
}

#ifdef __cplusplus
}; /* extern "C" */
#endif

#endif /* __P448_H__ */