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gf_w16.c
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gf_w16.c
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/*
* GF-Complete: A Comprehensive Open Source Library for Galois Field Arithmetic
* James S. Plank, Ethan L. Miller, Kevin M. Greenan,
* Benjamin A. Arnold, John A. Burnum, Adam W. Disney, Allen C. McBride.
*
* gf_w16.c
*
* Routines for 16-bit Galois fields
*/
#include "gf_int.h"
#include <stdio.h>
#include <stdlib.h>
#include "gf_w16.h"
#define AB2(ip, am1 ,am2, b, t1, t2) {\
t1 = (b << 1) & am1;\
t2 = b & am2; \
t2 = ((t2 << 1) - (t2 >> (GF_FIELD_WIDTH-1))); \
b = (t1 ^ (t2 & ip));}
#define SSE_AB2(pp, m1 ,m2, va, t1, t2) {\
t1 = _mm_and_si128(_mm_slli_epi64(va, 1), m1); \
t2 = _mm_and_si128(va, m2); \
t2 = _mm_sub_epi64 (_mm_slli_epi64(t2, 1), _mm_srli_epi64(t2, (GF_FIELD_WIDTH-1))); \
va = _mm_xor_si128(t1, _mm_and_si128(t2, pp)); }
#define MM_PRINT(s, r) { uint8_t blah[16], ii; printf("%-12s", s); _mm_storeu_si128((__m128i *)blah, r); for (ii = 0; ii < 16; ii += 2) printf(" %02x %02x", blah[15-ii], blah[14-ii]); printf("\n"); }
#define GF_FIRST_BIT (1 << 15)
#define GF_MULTBY_TWO(p) (((p) & GF_FIRST_BIT) ? (((p) << 1) ^ h->prim_poly) : (p) << 1)
static
inline
gf_val_32_t gf_w16_inverse_from_divide (gf_t *gf, gf_val_32_t a)
{
return gf->divide.w32(gf, 1, a);
}
static
inline
gf_val_32_t gf_w16_divide_from_inverse (gf_t *gf, gf_val_32_t a, gf_val_32_t b)
{
b = gf->inverse.w32(gf, b);
return gf->multiply.w32(gf, a, b);
}
static
void
gf_w16_multiply_region_from_single(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
gf_region_data rd;
uint16_t *s16;
uint16_t *d16;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
if (xor) {
while (d16 < ((uint16_t *) rd.d_top)) {
*d16 ^= gf->multiply.w32(gf, val, *s16);
d16++;
s16++;
}
} else {
while (d16 < ((uint16_t *) rd.d_top)) {
*d16 = gf->multiply.w32(gf, val, *s16);
d16++;
s16++;
}
}
gf_do_final_region_alignment(&rd);
}
#if defined(INTEL_SSE4_PCLMUL)
static
void
gf_w16_clm_multiply_region_from_single_2(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
gf_region_data rd;
uint16_t *s16;
uint16_t *d16;
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
a = _mm_insert_epi32 (_mm_setzero_si128(), val, 0);
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
if (xor) {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 ^= ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
} else {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 = ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
}
gf_do_final_region_alignment(&rd);
}
#endif
#if defined(INTEL_SSE4_PCLMUL)
static
void
gf_w16_clm_multiply_region_from_single_3(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
gf_region_data rd;
uint16_t *s16;
uint16_t *d16;
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
a = _mm_insert_epi32 (_mm_setzero_si128(), val, 0);
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
if (xor) {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 ^= ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
} else {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 = ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
}
gf_do_final_region_alignment(&rd);
}
#endif
#if defined(INTEL_SSE4_PCLMUL)
static
void
gf_w16_clm_multiply_region_from_single_4(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
gf_region_data rd;
uint16_t *s16;
uint16_t *d16;
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
a = _mm_insert_epi32 (_mm_setzero_si128(), val, 0);
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
if (xor) {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 ^= ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
} else {
while (d16 < ((uint16_t *) rd.d_top)) {
/* see gf_w16_clm_multiply() to see explanation of method */
b = _mm_insert_epi32 (a, (gf_val_32_t)(*s16), 0);
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
*d16 = ((gf_val_32_t)_mm_extract_epi32(result, 0));
d16++;
s16++;
}
}
gf_do_final_region_alignment(&rd);
}
#endif
static
inline
gf_val_32_t gf_w16_euclid (gf_t *gf, gf_val_32_t b)
{
gf_val_32_t e_i, e_im1, e_ip1;
gf_val_32_t d_i, d_im1, d_ip1;
gf_val_32_t y_i, y_im1, y_ip1;
gf_val_32_t c_i;
if (b == 0) return -1;
e_im1 = ((gf_internal_t *) (gf->scratch))->prim_poly;
e_i = b;
d_im1 = 16;
for (d_i = d_im1; ((1 << d_i) & e_i) == 0; d_i--) ;
y_i = 1;
y_im1 = 0;
while (e_i != 1) {
e_ip1 = e_im1;
d_ip1 = d_im1;
c_i = 0;
while (d_ip1 >= d_i) {
c_i ^= (1 << (d_ip1 - d_i));
e_ip1 ^= (e_i << (d_ip1 - d_i));
if (e_ip1 == 0) return 0;
while ((e_ip1 & (1 << d_ip1)) == 0) d_ip1--;
}
y_ip1 = y_im1 ^ gf->multiply.w32(gf, c_i, y_i);
y_im1 = y_i;
y_i = y_ip1;
e_im1 = e_i;
d_im1 = d_i;
e_i = e_ip1;
d_i = d_ip1;
}
return y_i;
}
static
gf_val_32_t gf_w16_extract_word(gf_t *gf, void *start, int bytes, int index)
{
uint16_t *r16, rv;
r16 = (uint16_t *) start;
rv = r16[index];
return rv;
}
static
gf_val_32_t gf_w16_composite_extract_word(gf_t *gf, void *start, int bytes, int index)
{
int sub_size;
gf_internal_t *h;
uint8_t *r8, *top;
uint16_t a, b, *r16;
gf_region_data rd;
h = (gf_internal_t *) gf->scratch;
gf_set_region_data(&rd, gf, start, start, bytes, 0, 0, 32);
r16 = (uint16_t *) start;
if (r16 + index < (uint16_t *) rd.d_start) return r16[index];
if (r16 + index >= (uint16_t *) rd.d_top) return r16[index];
index -= (((uint16_t *) rd.d_start) - r16);
r8 = (uint8_t *) rd.d_start;
top = (uint8_t *) rd.d_top;
sub_size = (top-r8)/2;
a = h->base_gf->extract_word.w32(h->base_gf, r8, sub_size, index);
b = h->base_gf->extract_word.w32(h->base_gf, r8+sub_size, sub_size, index);
return (a | (b << 8));
}
static
gf_val_32_t gf_w16_split_extract_word(gf_t *gf, void *start, int bytes, int index)
{
uint16_t *r16, rv;
uint8_t *r8;
gf_region_data rd;
gf_set_region_data(&rd, gf, start, start, bytes, 0, 0, 32);
r16 = (uint16_t *) start;
if (r16 + index < (uint16_t *) rd.d_start) return r16[index];
if (r16 + index >= (uint16_t *) rd.d_top) return r16[index];
index -= (((uint16_t *) rd.d_start) - r16);
r8 = (uint8_t *) rd.d_start;
r8 += ((index & 0xfffffff0)*2);
r8 += (index & 0xf);
rv = (*r8 << 8);
r8 += 16;
rv |= *r8;
return rv;
}
static
inline
gf_val_32_t gf_w16_matrix (gf_t *gf, gf_val_32_t b)
{
return gf_bitmatrix_inverse(b, 16, ((gf_internal_t *) (gf->scratch))->prim_poly);
}
/* JSP: GF_MULT_SHIFT: The world's dumbest multiplication algorithm. I only
include it for completeness. It does have the feature that it requires no
extra memory.
*/
static
inline
gf_val_32_t
gf_w16_clm_multiply_2 (gf_t *gf, gf_val_32_t a16, gf_val_32_t b16)
{
gf_val_32_t rv = 0;
#if defined(INTEL_SSE4_PCLMUL)
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
a = _mm_insert_epi32 (_mm_setzero_si128(), a16, 0);
b = _mm_insert_epi32 (a, b16, 0);
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
/* Do the initial multiply */
result = _mm_clmulepi64_si128 (a, b, 0);
/* Ben: Do prim_poly reduction twice. We are guaranteed that we will only
have to do the reduction at most twice, because (w-2)/z == 2. Where
z is equal to the number of zeros after the leading 1
_mm_clmulepi64_si128 is the carryless multiply operation. Here
_mm_srli_si128 shifts the result to the right by 2 bytes. This allows
us to multiply the prim_poly by the leading bits of the result. We
then xor the result of that operation back with the result.*/
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
/* Extracts 32 bit value from result. */
rv = ((gf_val_32_t)_mm_extract_epi32(result, 0));
#endif
return rv;
}
static
inline
gf_val_32_t
gf_w16_clm_multiply_3 (gf_t *gf, gf_val_32_t a16, gf_val_32_t b16)
{
gf_val_32_t rv = 0;
#if defined(INTEL_SSE4_PCLMUL)
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
a = _mm_insert_epi32 (_mm_setzero_si128(), a16, 0);
b = _mm_insert_epi32 (a, b16, 0);
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
/* Do the initial multiply */
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
/* Extracts 32 bit value from result. */
rv = ((gf_val_32_t)_mm_extract_epi32(result, 0));
#endif
return rv;
}
static
inline
gf_val_32_t
gf_w16_clm_multiply_4 (gf_t *gf, gf_val_32_t a16, gf_val_32_t b16)
{
gf_val_32_t rv = 0;
#if defined(INTEL_SSE4_PCLMUL)
__m128i a, b;
__m128i result;
__m128i prim_poly;
__m128i w;
gf_internal_t * h = gf->scratch;
a = _mm_insert_epi32 (_mm_setzero_si128(), a16, 0);
b = _mm_insert_epi32 (a, b16, 0);
prim_poly = _mm_set_epi32(0, 0, 0, (uint32_t)(h->prim_poly & 0x1ffffULL));
/* Do the initial multiply */
result = _mm_clmulepi64_si128 (a, b, 0);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
w = _mm_clmulepi64_si128 (prim_poly, _mm_srli_si128 (result, 2), 0);
result = _mm_xor_si128 (result, w);
/* Extracts 32 bit value from result. */
rv = ((gf_val_32_t)_mm_extract_epi32(result, 0));
#endif
return rv;
}
static
inline
gf_val_32_t
gf_w16_shift_multiply (gf_t *gf, gf_val_32_t a16, gf_val_32_t b16)
{
gf_val_32_t product, i, pp, a, b;
gf_internal_t *h;
a = a16;
b = b16;
h = (gf_internal_t *) gf->scratch;
pp = h->prim_poly;
product = 0;
for (i = 0; i < GF_FIELD_WIDTH; i++) {
if (a & (1 << i)) product ^= (b << i);
}
for (i = (GF_FIELD_WIDTH*2-2); i >= GF_FIELD_WIDTH; i--) {
if (product & (1 << i)) product ^= (pp << (i-GF_FIELD_WIDTH));
}
return product;
}
static
int gf_w16_shift_init(gf_t *gf)
{
gf->multiply.w32 = gf_w16_shift_multiply;
return 1;
}
static
int gf_w16_cfm_init(gf_t *gf)
{
#if defined(INTEL_SSE4_PCLMUL)
gf_internal_t *h;
h = (gf_internal_t *) gf->scratch;
/*Ben: Determining how many reductions to do */
if ((0xfe00 & h->prim_poly) == 0) {
gf->multiply.w32 = gf_w16_clm_multiply_2;
gf->multiply_region.w32 = gf_w16_clm_multiply_region_from_single_2;
} else if((0xf000 & h->prim_poly) == 0) {
gf->multiply.w32 = gf_w16_clm_multiply_3;
gf->multiply_region.w32 = gf_w16_clm_multiply_region_from_single_3;
} else if ((0xe000 & h->prim_poly) == 0) {
gf->multiply.w32 = gf_w16_clm_multiply_4;
gf->multiply_region.w32 = gf_w16_clm_multiply_region_from_single_4;
} else {
return 0;
}
return 1;
#endif
return 0;
}
/* KMG: GF_MULT_LOGTABLE: */
static
void
gf_w16_log_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
uint16_t *s16, *d16;
int lv;
struct gf_w16_logtable_data *ltd;
gf_region_data rd;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
ltd = (struct gf_w16_logtable_data *) ((gf_internal_t *) gf->scratch)->private;
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
lv = ltd->log_tbl[val];
if (xor) {
while (d16 < (uint16_t *) rd.d_top) {
*d16 ^= (*s16 == 0 ? 0 : ltd->antilog_tbl[lv + ltd->log_tbl[*s16]]);
d16++;
s16++;
}
} else {
while (d16 < (uint16_t *) rd.d_top) {
*d16 = (*s16 == 0 ? 0 : ltd->antilog_tbl[lv + ltd->log_tbl[*s16]]);
d16++;
s16++;
}
}
gf_do_final_region_alignment(&rd);
}
static
inline
gf_val_32_t
gf_w16_log_multiply(gf_t *gf, gf_val_32_t a, gf_val_32_t b)
{
struct gf_w16_logtable_data *ltd;
ltd = (struct gf_w16_logtable_data *) ((gf_internal_t *) gf->scratch)->private;
return (a == 0 || b == 0) ? 0 : ltd->antilog_tbl[(int) ltd->log_tbl[a] + (int) ltd->log_tbl[b]];
}
static
inline
gf_val_32_t
gf_w16_log_divide(gf_t *gf, gf_val_32_t a, gf_val_32_t b)
{
int log_sum = 0;
struct gf_w16_logtable_data *ltd;
if (a == 0 || b == 0) return 0;
ltd = (struct gf_w16_logtable_data *) ((gf_internal_t *) gf->scratch)->private;
log_sum = (int) ltd->log_tbl[a] - (int) ltd->log_tbl[b];
return (ltd->d_antilog[log_sum]);
}
static
gf_val_32_t
gf_w16_log_inverse(gf_t *gf, gf_val_32_t a)
{
struct gf_w16_logtable_data *ltd;
ltd = (struct gf_w16_logtable_data *) ((gf_internal_t *) gf->scratch)->private;
return (ltd->inv_tbl[a]);
}
static
int gf_w16_log_init(gf_t *gf)
{
gf_internal_t *h;
struct gf_w16_logtable_data *ltd;
int i, b;
int check = 0;
h = (gf_internal_t *) gf->scratch;
ltd = h->private;
for (i = 0; i < GF_MULT_GROUP_SIZE+1; i++)
ltd->log_tbl[i] = 0;
ltd->d_antilog = ltd->antilog_tbl + GF_MULT_GROUP_SIZE;
b = 1;
for (i = 0; i < GF_MULT_GROUP_SIZE; i++) {
if (ltd->log_tbl[b] != 0) check = 1;
ltd->log_tbl[b] = i;
ltd->antilog_tbl[i] = b;
ltd->antilog_tbl[i+GF_MULT_GROUP_SIZE] = b;
b <<= 1;
if (b & GF_FIELD_SIZE) {
b = b ^ h->prim_poly;
}
}
/* If you can't construct the log table, there's a problem. This code is used for
some other implementations (e.g. in SPLIT), so if the log table doesn't work in
that instance, use CARRY_FREE / SHIFT instead. */
if (check) {
if (h->mult_type != GF_MULT_LOG_TABLE) {
#if defined(INTEL_SSE4_PCLMUL)
return gf_w16_cfm_init(gf);
#endif
return gf_w16_shift_init(gf);
} else {
_gf_errno = GF_E_LOGPOLY;
return 0;
}
}
ltd->inv_tbl[0] = 0; /* Not really, but we need to fill it with something */
ltd->inv_tbl[1] = 1;
for (i = 2; i < GF_FIELD_SIZE; i++) {
ltd->inv_tbl[i] = ltd->antilog_tbl[GF_MULT_GROUP_SIZE-ltd->log_tbl[i]];
}
gf->inverse.w32 = gf_w16_log_inverse;
gf->divide.w32 = gf_w16_log_divide;
gf->multiply.w32 = gf_w16_log_multiply;
gf->multiply_region.w32 = gf_w16_log_multiply_region;
return 1;
}
/* JSP: GF_MULT_SPLIT_TABLE: Using 8 multiplication tables to leverage SSE instructions.
*/
/* Ben: Does alternate mapping multiplication using a split table in the
lazy method without sse instructions*/
static
void
gf_w16_split_4_16_lazy_nosse_altmap_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
uint64_t i, j, c, prod;
uint8_t *s8, *d8, *top;
uint16_t table[4][16];
gf_region_data rd;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 32);
gf_do_initial_region_alignment(&rd);
/*Ben: Constructs lazy multiplication table*/
for (j = 0; j < 16; j++) {
for (i = 0; i < 4; i++) {
c = (j << (i*4));
table[i][j] = gf->multiply.w32(gf, c, val);
}
}
/*Ben: s8 is the start of source, d8 is the start of dest, top is end of dest region. */
s8 = (uint8_t *) rd.s_start;
d8 = (uint8_t *) rd.d_start;
top = (uint8_t *) rd.d_top;
while (d8 < top) {
/*Ben: Multiplies across 16 two byte quantities using alternate mapping
high bits are on the left, low bits are on the right. */
for (j=0;j<16;j++) {
/*Ben: If the xor flag is set, the product should include what is in dest */
prod = (xor) ? ((uint16_t)(*d8)<<8) ^ *(d8+16) : 0;
/*Ben: xors all 4 table lookups into the product variable*/
prod ^= ((table[0][*(s8+16)&0xf]) ^
(table[1][(*(s8+16)&0xf0)>>4]) ^
(table[2][*(s8)&0xf]) ^
(table[3][(*(s8)&0xf0)>>4]));
/*Ben: Stores product in the destination and moves on*/
*d8 = (uint8_t)(prod >> 8);
*(d8+16) = (uint8_t)(prod & 0x00ff);
s8++;
d8++;
}
s8+=16;
d8+=16;
}
gf_do_final_region_alignment(&rd);
}
static
void
gf_w16_split_4_16_lazy_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
uint64_t i, j, a, c, prod;
uint16_t *s16, *d16, *top;
uint16_t table[4][16];
gf_region_data rd;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 2);
gf_do_initial_region_alignment(&rd);
for (j = 0; j < 16; j++) {
for (i = 0; i < 4; i++) {
c = (j << (i*4));
table[i][j] = gf->multiply.w32(gf, c, val);
}
}
s16 = (uint16_t *) rd.s_start;
d16 = (uint16_t *) rd.d_start;
top = (uint16_t *) rd.d_top;
while (d16 < top) {
a = *s16;
prod = (xor) ? *d16 : 0;
for (i = 0; i < 4; i++) {
prod ^= table[i][a&0xf];
a >>= 4;
}
*d16 = prod;
s16++;
d16++;
}
}
static
void
gf_w16_split_8_16_lazy_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
uint64_t j, k, v, a, prod, *s64, *d64, *top64;
gf_internal_t *h;
uint64_t htable[256], ltable[256];
gf_region_data rd;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 8);
gf_do_initial_region_alignment(&rd);
h = (gf_internal_t *) gf->scratch;
v = val;
ltable[0] = 0;
for (j = 1; j < 256; j <<= 1) {
for (k = 0; k < j; k++) ltable[k^j] = (v ^ ltable[k]);
v = GF_MULTBY_TWO(v);
}
htable[0] = 0;
for (j = 1; j < 256; j <<= 1) {
for (k = 0; k < j; k++) htable[k^j] = (v ^ htable[k]);
v = GF_MULTBY_TWO(v);
}
s64 = (uint64_t *) rd.s_start;
d64 = (uint64_t *) rd.d_start;
top64 = (uint64_t *) rd.d_top;
/* Does Unrolling Matter? -- Doesn't seem to.
while (d64 != top64) {
a = *s64;
prod = htable[a >> 56];
a <<= 8;
prod ^= ltable[a >> 56];
a <<= 8;
prod <<= 16;
prod ^= htable[a >> 56];
a <<= 8;
prod ^= ltable[a >> 56];
a <<= 8;
prod <<= 16;
prod ^= htable[a >> 56];
a <<= 8;
prod ^= ltable[a >> 56];
a <<= 8;
prod <<= 16;
prod ^= htable[a >> 56];
a <<= 8;
prod ^= ltable[a >> 56];
prod ^= ((xor) ? *d64 : 0);
*d64 = prod;
s64++;
d64++;
}
*/
while (d64 != top64) {
a = *s64;
prod = 0;
for (j = 0; j < 4; j++) {
prod <<= 16;
prod ^= htable[a >> 56];
a <<= 8;
prod ^= ltable[a >> 56];
a <<= 8;
}
//JSP: We can move the conditional outside the while loop, but we need to fully test it to understand which is better.
prod ^= ((xor) ? *d64 : 0);
*d64 = prod;
s64++;
d64++;
}
gf_do_final_region_alignment(&rd);
}
static void
gf_w16_table_lazy_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
uint64_t c;
gf_internal_t *h;
struct gf_w16_lazytable_data *ltd;
gf_region_data rd;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 8);
gf_do_initial_region_alignment(&rd);
h = (gf_internal_t *) gf->scratch;
ltd = (struct gf_w16_lazytable_data *) h->private;
ltd->lazytable[0] = 0;
/*
a = val;
c = 1;
pp = h->prim_poly;
do {
ltd->lazytable[c] = a;
c <<= 1;
if (c & (1 << GF_FIELD_WIDTH)) c ^= pp;
a <<= 1;
if (a & (1 << GF_FIELD_WIDTH)) a ^= pp;
} while (c != 1);
*/
for (c = 1; c < GF_FIELD_SIZE; c++) {
ltd->lazytable[c] = gf_w16_shift_multiply(gf, c, val);
}
gf_two_byte_region_table_multiply(&rd, ltd->lazytable);
gf_do_final_region_alignment(&rd);
}
static
void
gf_w16_split_4_16_lazy_sse_multiply_region(gf_t *gf, void *src, void *dest, gf_val_32_t val, int bytes, int xor)
{
#ifdef INTEL_SSSE3
uint64_t i, j, *s64, *d64, *top64;;
uint64_t c, prod;
uint8_t low[4][16];
uint8_t high[4][16];
gf_region_data rd;
__m128i mask, ta, tb, ti, tpl, tph, tlow[4], thigh[4], tta, ttb, lmask;
if (val == 0) { gf_multby_zero(dest, bytes, xor); return; }
if (val == 1) { gf_multby_one(src, dest, bytes, xor); return; }
gf_set_region_data(&rd, gf, src, dest, bytes, val, xor, 32);
gf_do_initial_region_alignment(&rd);
for (j = 0; j < 16; j++) {
for (i = 0; i < 4; i++) {
c = (j << (i*4));
prod = gf->multiply.w32(gf, c, val);
low[i][j] = (prod & 0xff);
high[i][j] = (prod >> 8);
}
}
for (i = 0; i < 4; i++) {
tlow[i] = _mm_loadu_si128((__m128i *)low[i]);
thigh[i] = _mm_loadu_si128((__m128i *)high[i]);
}
s64 = (uint64_t *) rd.s_start;
d64 = (uint64_t *) rd.d_start;
top64 = (uint64_t *) rd.d_top;
mask = _mm_set1_epi8 (0x0f);
lmask = _mm_set1_epi16 (0xff);
if (xor) {
while (d64 != top64) {
ta = _mm_load_si128((__m128i *) s64);
tb = _mm_load_si128((__m128i *) (s64+2));
tta = _mm_srli_epi16(ta, 8);
ttb = _mm_srli_epi16(tb, 8);
tpl = _mm_and_si128(tb, lmask);
tph = _mm_and_si128(ta, lmask);