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c: big: fixup for signed overflow #79

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6 changes: 6 additions & 0 deletions c/arch.h
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Original file line number Diff line number Diff line change
Expand Up @@ -102,9 +102,11 @@
#define CONDMS 0xa55a
#ifndef C99
#define chunk __int16 /**< C type corresponding to word length */
#define chunku unsigned __int16 /**< Unsigned type corresponding to word length */
#define dchunk __int32 /**< Always define double length chunk type if available */
#else
#define chunk int16_t /**< C type corresponding to word length */
#define chunku uint16_t /**< Unsigned type corresponding to word length */
#define dchunk int32_t /**< Always define double length chunk type if available */
#endif
#endif
Expand All @@ -113,9 +115,11 @@
#define CONDMS 0x5aa5a55a
#ifndef C99
#define chunk __int32 /**< C type corresponding to word length */
#define chunku unsigned __int32 /**< Unsigned type corresponding to word length */
#define dchunk __int64 /**< Always define double length chunk type if available */
#else
#define chunk int32_t /**< C type corresponding to word length */
#define chunku uint32_t /**< Unsigned type corresponding to word length */
#define dchunk int64_t /**< Always define double length chunk type if available */
#endif
#endif
Expand All @@ -124,9 +128,11 @@
#define CONDMS 0x3cc3c33c5aa5a55a
#ifndef C99
#define chunk __int64 /**< C type corresponding to word length */
#define chunku unsigned __int64 /**< Unsigned type corresponding to word length */
/**< Note - no 128-bit type available */
#else
#define chunk int64_t /**< C type corresponding to word length */
#define chunku uint64_t /**< Unsigned type corresponding to word length */
//#ifdef __GNUC__
//#define dchunk __int128 /**< Always define double length chunk type if available - GCC supports 128 bit type ??? */
//#endif
Expand Down
138 changes: 70 additions & 68 deletions c/big.c
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Original file line number Diff line number Diff line change
Expand Up @@ -94,68 +94,68 @@ void BIG_XXX_rawoutput(BIG_XXX a)
chunk BIG_XXX_cmove(volatile BIG_XXX f, BIG_XXX g, int d)
{
int i;
chunk c0,c1,s,t,w,aux;
static chunk R=0;
R+=CONDMS;
chunku c0,c1,s,t,w,aux;
static chunku R=0;
R+=(chunku)CONDMS;
w=R;
c0=(~d)&(w+1);
c1=d+w;
c0=(~(chunku)d)&(w+1);
c1=(chunku)d+w;
#ifdef DEBUG_NORM
for (i = 0; i < NLEN_XXX + 2; i++)
#else
for (i = 0; i < NLEN_XXX; i++)
#endif
{
s=g[i]; t=f[i];
f[i] =aux=c0*t+c1*s;
f[i] =aux-w*(t+s);
s=(chunku)g[i]; t=(chunku)f[i];
f[i] =(chunk)(aux=c0*t+c1*s);
f[i] =(chunk)(aux-w*(t+s));
}
return 0;
}

chunk BIG_XXX_cswap(volatile BIG_XXX f, volatile BIG_XXX g, int d)
{
int i;
chunk c0,c1,s,t,w,v,aux;
static chunk R=0;
R+=CONDMS;
chunku c0,c1,s,t,w,v,aux;
static chunku R=0;
R+=(chunku)CONDMS;
w=R;
c0=(~d)&(w+1);
c1=d+w;
c0=(~(chunku)d)&(w+1);
c1=(chunku)d+w;
#ifdef DEBUG_NORM
for (i = 0; i < NLEN_XXX + 2; i++)
#else
for (i = 0; i < NLEN_XXX; i++)
#endif
{
s=g[i]; t=f[i];
s=(chunku)g[i]; t=(chunku)f[i];
v=w*(t+s);
f[i] =aux=c0*t+c1*s;
f[i] =aux-v;
g[i] =aux=c0*s+c1*t;
g[i] =aux-v;
f[i] =(chunk)(aux=c0*t+c1*s);
f[i] =(chunk)(aux-v);
g[i] =(chunk)(aux=c0*s+c1*t);
g[i] =(chunk)(aux-v);
}
return 0;
}

chunk BIG_XXX_dcmove(volatile DBIG_XXX f, DBIG_XXX g, int d)
{
int i;
chunk c0,c1,s,t,w,aux;
static chunk R=0;
R+=CONDMS;
chunku c0,c1,s,t,w,aux;
static chunku R=0;
R+=(chunku)CONDMS;
w=R;
c0=(~d)&(w+1);
c1=d+w;
c0=(~(chunku)d)&(w+1);
c1=(chunku)d+w;
#ifdef DEBUG_NORM
for (i = 0; i < DNLEN_XXX + 2; i++)
#else
for (i = 0; i < DNLEN_XXX; i++)
#endif
{
s=g[i]; t=f[i];
f[i] =aux=c0*t+c1*s;
f[i] =aux-w*(t+s);
s=(chunku)g[i]; t=(chunku)f[i];
f[i] =(chunk)(aux=c0*t+c1*s);
f[i] =(chunk)(aux-w*(t+s));
}
return 0;
}
Expand Down Expand Up @@ -577,9 +577,10 @@ chunk BIG_XXX_pmul(BIG_XXX r, BIG_XXX a, int c)
int BIG_XXX_div3(BIG_XXX r)
{
int i;
chunk ak, base, carry = 0;
chunk ak, carry = 0;
chunku base;
BIG_XXX_norm(r);
base = ((chunk)1 << BASEBITS_XXX);
base = ((chunku)1 << BASEBITS_XXX);
for (i = NLEN_XXX - 1; i >= 0; i--)
{
ak = (carry * base + r[i]);
Expand Down Expand Up @@ -706,15 +707,15 @@ void BIG_XXX_mul(DBIG_XXX c, BIG_XXX a, BIG_XXX b)
t = co + s;

/*for (i = k; i >= 1 + k / 2; i--) This causes a huge slow down! gcc/g++ optimizer problem (I think) */
for (i=1+k/2;i<=k;i++) t += (dchunk)(a[i] - a[k - i]) * (b[k - i] - b[i]);
for (i=1+k/2;i<=k;i++) t += (((dchunk)a[i] - (dchunk)a[k - i]) * ((dchunk)b[k - i] - (dchunk)b[i]));
c[k] = (chunk)t & BMASK_XXX;
co = t >> BASEBITS_XXX;
}
for (k = NLEN_XXX; k < 2 * NLEN_XXX - 1; k++)
{
s -= d[k - NLEN_XXX];
t = co + s;
for (i=1+k/2;i<NLEN_XXX;i++) t += (dchunk)(a[i] - a[k - i]) * (b[k - i] - b[i]);
for (i=1+k/2;i<NLEN_XXX;i++) t += (((dchunk)a[i] - (dchunk)a[k - i]) * ((dchunk)b[k - i] - (dchunk)b[i]));
c[k] = (chunk)t & BMASK_XXX;
co = t >> BASEBITS_XXX;
}
Expand Down Expand Up @@ -897,7 +898,7 @@ void BIG_XXX_monty(BIG_XXX a, BIG_XXX md, chunk MC, DBIG_XXX d)
#else
#ifndef USE_KARATSUBA
t = d[0];
v[0] = ((chunk)t * MC)&BMASK_XXX;
v[0] = (chunk)(((chunku)t * (chunku)MC)&(chunku)BMASK_XXX);
t += (dchunk)v[0] * md[0];
t = (t >> BASEBITS_XXX) + d[1];

Expand Down Expand Up @@ -928,8 +929,8 @@ void BIG_XXX_monty(BIG_XXX a, BIG_XXX md, chunk MC, DBIG_XXX d)
for (k = 1; k < NLEN_XXX; k++)
{
t = c + s + (dchunk)v[0] * md[k];
for (i=1+k/2;i<k;i++) t += (dchunk)(v[k - i] - v[i]) * (md[i] - md[k - i]);
v[k] = ((chunk)t * MC)&BMASK_XXX;
for (i=1+k/2;i<k;i++) t += (((dchunk)v[k - i] - (dchunk)v[i]) * ((dchunk)md[i] - (dchunk)md[k - i]));
v[k] = (chunk)(((chunku)t * (chunku)MC)&(chunku)BMASK_XXX);
t += (dchunk)v[k] * md[0];
c = (t >> BASEBITS_XXX) + d[k + 1];
dd[k] = (dchunk)v[k] * md[k];
Expand All @@ -938,7 +939,7 @@ void BIG_XXX_monty(BIG_XXX a, BIG_XXX md, chunk MC, DBIG_XXX d)
for (k = NLEN_XXX; k < 2 * NLEN_XXX - 1; k++)
{
t = c + s;
for (i=1+k/2;i<NLEN_XXX;i++) t += (dchunk)(v[k - i] - v[i]) * (md[i] - md[k - i]);
for (i=1+k/2;i<NLEN_XXX;i++) t += (((dchunk)v[k - i] - (dchunk)v[i]) * ((dchunk)md[i] - (dchunk)md[k - i]));
a[k - NLEN_XXX] = (chunk)t & BMASK_XXX;
c = (t >> BASEBITS_XXX) + d[k + 1];
s -= dd[k - NLEN_XXX + 1];
Expand All @@ -954,11 +955,11 @@ void BIG_XXX_monty(BIG_XXX a, BIG_XXX md, chunk MC, DBIG_XXX d)
chunk m, carry;
for (i = 0; i < NLEN_XXX; i++)
{
if (MC == -1) m = (-d[i])&BMASK_XXX;
if (MC == -1) m = (chunk)(-(chunku)d[i])&BMASK_XXX;
else
{
if (MC == 1) m = d[i];
else m = (MC * d[i])&BMASK_XXX;
else m = (chunk)(((chunku)MC * (chunku)d[i])&(chunku)BMASK_XXX);
}
carry = 0;
for (j = 0; j < NLEN_XXX; j++)
Expand All @@ -985,12 +986,12 @@ void BIG_XXX_shl(BIG_XXX a, int k)
int n = k % BASEBITS_XXX;
int m = k / BASEBITS_XXX;

a[NLEN_XXX - 1] = ((a[NLEN_XXX - 1 - m] << n));
if (NLEN_XXX >= m + 2) a[NLEN_XXX - 1] |= (a[NLEN_XXX - m - 2] >> (BASEBITS_XXX - n));
a[NLEN_XXX - 1] = (chunk)((chunku)a[NLEN_XXX - 1 - m] << n);
if (NLEN_XXX >= m + 2) a[NLEN_XXX - 1] |= (chunk)((chunku)a[NLEN_XXX - m - 2] >> (BASEBITS_XXX - n));

for (i = NLEN_XXX - 2; i > m; i--)
a[i] = ((a[i - m] << n)&BMASK_XXX) | (a[i - m - 1] >> (BASEBITS_XXX - n));
a[m] = (a[0] << n)&BMASK_XXX;
a[i] = (chunk)((((chunku)a[i - m] << n)&(chunku)BMASK_XXX) | ((chunku)a[i - m - 1] >> (BASEBITS_XXX - n)));
a[m] = (chunk)(((chunku)a[0] << n)&(chunku)BMASK_XXX);
for (i = 0; i < m; i++) a[i] = 0;

}
Expand All @@ -1002,10 +1003,10 @@ int BIG_XXX_fshl(BIG_XXX a, int n)
{
int i;

a[NLEN_XXX - 1] = ((a[NLEN_XXX - 1] << n)) | (a[NLEN_XXX - 2] >> (BASEBITS_XXX - n)); /* top word not masked */
a[NLEN_XXX - 1] = (chunk)(((chunku)a[NLEN_XXX - 1] << n) | ((chunku)a[NLEN_XXX - 2] >> (BASEBITS_XXX - n))); /* top word not masked */
for (i = NLEN_XXX - 2; i > 0; i--)
a[i] = ((a[i] << n)&BMASK_XXX) | (a[i - 1] >> (BASEBITS_XXX - n));
a[0] = (a[0] << n)&BMASK_XXX;
a[i] = (chunk)((((chunku)a[i] << n)&(chunku)BMASK_XXX) | ((chunku)a[i - 1] >> (BASEBITS_XXX - n)));
a[0] = (chunk)(((chunku)a[0] << n)&(chunku)BMASK_XXX);

return (int)(a[NLEN_XXX - 1] >> ((8 * MODBYTES_XXX) % BASEBITS_XXX)); /* return excess - only used in ff.c */
}
Expand All @@ -1018,11 +1019,11 @@ void BIG_XXX_dshl(DBIG_XXX a, int k)
int n = k % BASEBITS_XXX;
int m = k / BASEBITS_XXX;

a[DNLEN_XXX - 1] = ((a[DNLEN_XXX - 1 - m] << n)) | (a[DNLEN_XXX - m - 2] >> (BASEBITS_XXX - n));
a[DNLEN_XXX - 1] = (chunk)(((chunku)a[DNLEN_XXX - 1 - m] << n) | ((chunku)a[DNLEN_XXX - m - 2] >> (BASEBITS_XXX - n)));

for (i = DNLEN_XXX - 2; i > m; i--)
a[i] = ((a[i - m] << n)&BMASK_XXX) | (a[i - m - 1] >> (BASEBITS_XXX - n));
a[m] = (a[0] << n)&BMASK_XXX;
a[i] = (chunk)((((chunku)a[i - m] << n)&(chunku)BMASK_XXX) | ((chunku)a[i - m - 1] >> (BASEBITS_XXX - n)));
a[m] = (chunk)(((chunku)a[0] << n)&(chunku)BMASK_XXX);
for (i = 0; i < m; i++) a[i] = 0;

}
Expand All @@ -1036,8 +1037,8 @@ void BIG_XXX_shr(BIG_XXX a, int k)
int n = k % BASEBITS_XXX;
int m = k / BASEBITS_XXX;
for (i = 0; i < NLEN_XXX - m - 1; i++)
a[i] = (a[m + i] >> n) | ((a[m + i + 1] << (BASEBITS_XXX - n))&BMASK_XXX);
if (NLEN_XXX > m) a[NLEN_XXX - m - 1] = a[NLEN_XXX - 1] >> n;
a[i] = (chunk)(((chunku)a[m + i] >> n) | (((chunku)a[m + i + 1] << (BASEBITS_XXX - n))&(chunku)BMASK_XXX));
if (NLEN_XXX > m) a[NLEN_XXX - m - 1] = (chunk)((chunku)a[NLEN_XXX - 1] >> n);
for (i = NLEN_XXX - m; i < NLEN_XXX; i++) a[i] = 0;

}
Expand All @@ -1047,17 +1048,18 @@ int BIG_XXX_ssn(BIG_XXX r, BIG_XXX a, BIG_XXX m)
{
int i, n = NLEN_XXX - 1;
chunk carry;
m[0] = (m[0] >> 1) | ((m[1] << (BASEBITS_XXX - 1))&BMASK_XXX);
r[0] = a[0] - m[0];
carry = r[0] >> BASEBITS_XXX;
r[0] &= BMASK_XXX;
dchunk delta;
m[0] = (chunk)(((chunku)m[0] >> 1) | (((chunku)m[1] << (BASEBITS_XXX - 1))&(chunku)BMASK_XXX));
delta = (dchunk)a[0] - (dchunk)m[0];
carry = (delta < 0) ? (chunk)-1 : 0;
r[0] = (chunk)((chunku)delta & (chunku)BMASK_XXX);

for (i = 1; i < n; i++)
{
m[i] = (m[i] >> 1) | ((m[i + 1] << (BASEBITS_XXX - 1))&BMASK_XXX);
r[i] = a[i] - m[i] + carry;
carry = r[i] >> BASEBITS_XXX;
r[i] &= BMASK_XXX;
m[i] = (chunk)(((chunku)m[i] >> 1) | (((chunku)m[i + 1] << (BASEBITS_XXX - 1))&(chunku)BMASK_XXX));
delta = (dchunk)a[i] - (dchunk)m[i] + (dchunk)carry;
carry = (delta < 0) ? (chunk)-1 : 0;
r[i] = (chunk)((chunku)delta & (chunku)BMASK_XXX);
}

m[n] >>= 1;
Expand All @@ -1066,7 +1068,7 @@ int BIG_XXX_ssn(BIG_XXX r, BIG_XXX a, BIG_XXX m)
r[MPV_XXX] = 1;
r[MNV_XXX] = 0;
#endif
return ((r[n] >> (CHUNK - 1)) & 1);
return (int)(((chunku)r[n] >> (CHUNK - 1)) & 1);
}

/* Faster shift right of a by k bits. Return shifted out part */
Expand All @@ -1075,10 +1077,10 @@ int BIG_XXX_ssn(BIG_XXX r, BIG_XXX a, BIG_XXX m)
int BIG_XXX_fshr(BIG_XXX a, int k)
{
int i;
chunk r = a[0] & (((chunk)1 << k) - 1); /* shifted out part */
chunk r = (chunk)((chunku)a[0] & (((chunku)1 << k) - 1)); /* shifted out part */
for (i = 0; i < NLEN_XXX - 1; i++)
a[i] = (a[i] >> k) | ((a[i + 1] << (BASEBITS_XXX - k))&BMASK_XXX);
a[NLEN_XXX - 1] = a[NLEN_XXX - 1] >> k;
a[i] = (chunk)(((chunku)a[i] >> k) | (((chunku)a[i + 1] << (BASEBITS_XXX - k))&(chunku)BMASK_XXX));
a[NLEN_XXX - 1] = (chunk)((chunku)a[NLEN_XXX - 1] >> k);
return (int)r;
}

Expand All @@ -1090,8 +1092,8 @@ void BIG_XXX_dshr(DBIG_XXX a, int k)
int n = k % BASEBITS_XXX;
int m = k / BASEBITS_XXX;
for (i = 0; i < DNLEN_XXX - m - 1; i++)
a[i] = (a[m + i] >> n) | ((a[m + i + 1] << (BASEBITS_XXX - n))&BMASK_XXX);
a[DNLEN_XXX - m - 1] = a[DNLEN_XXX - 1] >> n;
a[i] = (chunk)(((chunku)a[m + i] >> n) | (((chunku)a[m + i + 1] << (BASEBITS_XXX - n))&(chunku)BMASK_XXX));
a[DNLEN_XXX - m - 1] = (chunk)((chunku)a[DNLEN_XXX - 1] >> n);
for (i = DNLEN_XXX - m; i < DNLEN_XXX; i++ ) a[i] = 0;
}

Expand All @@ -1118,15 +1120,15 @@ chunk BIG_XXX_split(BIG_XXX t, BIG_XXX b, DBIG_XXX d, int n)

for (i = 0; i < NLEN_XXX - 1; i++) b[i] = d[i];

b[NLEN_XXX - 1] = d[NLEN_XXX - 1] & (((chunk)1 << m) - 1);
b[NLEN_XXX - 1] = (chunk)((chunku)d[NLEN_XXX - 1] & (((chunku)1 << m) - 1));

if (t != b)
{
carry = (d[DNLEN_XXX - 1] << (BASEBITS_XXX - m));
carry = (chunk)((chunku)d[DNLEN_XXX - 1] << (BASEBITS_XXX - m));
for (i = DNLEN_XXX - 2; i >= NLEN_XXX - 1; i--)
{
nw = (d[i] >> m) | carry;
carry = (d[i] << (BASEBITS_XXX - m))&BMASK_XXX;
nw = (chunk)(((chunku)d[i] >> m) | (chunku)carry);
carry = (chunk)(((chunku)d[i] << (BASEBITS_XXX - m))&(chunku)BMASK_XXX);
t[i - NLEN_XXX + 1] = nw;
}
}
Expand Down Expand Up @@ -1405,7 +1407,7 @@ int BIG_XXX_parity(BIG_XXX a)
/* SU= 16 */
int BIG_XXX_bit(BIG_XXX a, int n)
{
return (int)((a[n / BASEBITS_XXX] & ((chunk)1 << (n % BASEBITS_XXX))) >> (n%BASEBITS_XXX));
return (int)(((chunku)a[n / BASEBITS_XXX] & ((chunku)1 << (n % BASEBITS_XXX))) >> (n%BASEBITS_XXX));
// if (a[n / BASEBITS_XXX] & ((chunk)1 << (n % BASEBITS_XXX))) return 1;
// else return 0;
}
Expand Down Expand Up @@ -1737,7 +1739,7 @@ void BIG_XXX_mod2m(BIG_XXX x, int m)

wd = m / BASEBITS_XXX;
bt = m % BASEBITS_XXX;
msk = ((chunk)1 << bt) - 1;
msk = (chunk)(((chunku)1 << bt) - 1);
x[wd] &= msk;
for (i = wd + 1; i < NLEN_XXX; i++) x[i] = 0;
}
Expand Down
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