62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
|
#define MAKE_FN_NAME1(x,y) x ## y
|
||
|
|
#define MAKE_FN_NAME(x,y) MAKE_FN_NAME1(x,y)
|
||
|
|
|
||
|
|
#define PRECOMP MAKE_FN_NAME(CURVE_DESCRIPTION,_divstep_precomp)
|
||
|
|
#define MSAT MAKE_FN_NAME(CURVE_DESCRIPTION,_msat)
|
||
|
|
#define MONE MAKE_FN_NAME(CURVE_DESCRIPTION,_set_one)
|
||
|
|
#define DIVSTEP MAKE_FN_NAME(CURVE_DESCRIPTION,_divstep)
|
||
|
|
#define OPP MAKE_FN_NAME(CURVE_DESCRIPTION,_opp)
|
||
|
|
#define MUL MAKE_FN_NAME(CURVE_DESCRIPTION,_mul)
|
||
|
|
#define SZNZ MAKE_FN_NAME(CURVE_DESCRIPTION,_selectznz)
|
||
|
|
|
||
|
|
#if LEN_PRIME < 46
|
||
|
|
#define ITERATIONS (((49 * LEN_PRIME) + 80) / 17)
|
||
|
|
#else
|
||
|
|
#define ITERATIONS (((49 * LEN_PRIME) + 57) / 17)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define SAT_LIMBS LIMBS + 1 /* we might need 2 more bits to represent m in twos complement */
|
||
|
|
#define BYTES 8 * (((LEN_PRIME - 1) / 64) + 1)
|
||
|
|
|
||
|
|
static void inverse(WORD out[LIMBS], WORD g[SAT_LIMBS]) {
|
||
|
|
|
||
|
|
WORD precomp[LIMBS];
|
||
|
|
PRECOMP(precomp);
|
||
|
|
|
||
|
|
WORD d = 1;
|
||
|
|
WORD f[SAT_LIMBS];
|
||
|
|
WORD v[LIMBS];
|
||
|
|
WORD r[LIMBS];
|
||
|
|
WORD out1;
|
||
|
|
WORD out2[SAT_LIMBS], out3[SAT_LIMBS], out4[LIMBS], out5[LIMBS];
|
||
|
|
|
||
|
|
MSAT(f);
|
||
|
|
MONE(r);
|
||
|
|
for (int j = 0; j < LIMBS; j++) v[j] = 0;
|
||
|
|
|
||
|
|
for (int i = 0; i < ITERATIONS - (ITERATIONS % 2); i+=2) {
|
||
|
|
DIVSTEP(&out1,out2,out3,out4,out5,d,f,g,v,r);
|
||
|
|
DIVSTEP(&d,f,g,v,r,out1,out2,out3,out4,out5);
|
||
|
|
}
|
||
|
|
if (ITERATIONS % 2) {
|
||
|
|
DIVSTEP(&out1,out2,out3,out4,out5,d,f,g,v,r);
|
||
|
|
for (int k = 0; k < LIMBS; k++) v[k] = out4[k];
|
||
|
|
for (int k = 0; k < SAT_LIMBS; k++) f[k] = out2[k];
|
||
|
|
}
|
||
|
|
|
||
|
|
WORD h[LIMBS];
|
||
|
|
OPP(h, v);
|
||
|
|
SZNZ(v, f[SAT_LIMBS -1 ] >> (WORDSIZE - 1), v, h);
|
||
|
|
MUL(out, v, precomp);
|
||
|
|
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void inversion (WORD out[LIMBS], const WORD in[LIMBS]) {
|
||
|
|
WORD in_[SAT_LIMBS];
|
||
|
|
for (int i = 0; i < LIMBS; i++) in_[i] = in[i];
|
||
|
|
in_[LIMBS] = 0;
|
||
|
|
inverse(out, in_);
|
||
|
|
return;
|
||
|
|
}
|