add-bitops patch

Adding bit operations to MPI.

* mpi/mpi.c (MAX, MIN): New macros.
(mp_2comp, mp_and, mp_or, mp_xor, mp_comp, mp_trunc, mp_shift,
mp_bit): New functions.

* mpi/mpi.h (mp_2comp, mp_and, mp_or, mp_xor, mp_comp, mp_trunc,
mp_shift, mp_bit): Declared.

2 files changed, 441 insertions, 0 deletions

diff --git a/mpi/mpi.c b/mpi/mpi.c
index 1d9da125..61575abc 100644
--- a/mpi/mpi.c
+++ b/mpi/mpi.c
@@ -16,6 +16,9 @@
 #include <ctype.h>
 #include <math.h>
 
+#define MAX(A, B) ((A) > (B) ? (A) : (B))
+#define MIN(A, B) ((A) < (B) ? (A) : (B))
+
 typedef unsigned char mem_t;
 extern mem_t *chk_calloc(size_t n, size_t size);
 
@@ -157,6 +160,7 @@ static const char *s_dmap_2 =
 mp_err   s_mp_grow(mp_int *mp, mp_size min);   /* increase allocated size */
 mp_err   s_mp_pad(mp_int *mp, mp_size min);    /* left pad with zeroes    */
 
+static int s_highest_bit(mp_digit n);
 int      s_highest_bit_mp(mp_int *a);
 mp_err   s_mp_set_bit(mp_int *a, int bit);
 
@@ -2334,6 +2338,430 @@ X:
 
 /* }}} */
 
+/*
+ * Convert a's bit vector to its two's complement, up to the
+ * number of words that it contains, storing result in b. The numeric value of
+ * this result depends on the size of mpi_digit. This is a building block for
+ * handling negative operands in the bit operations.
+ */
+mp_err mp_2comp(mp_int *a, mp_int *b, mp_size dig)
+{
+  mp_err res;
+  mp_size ix, adig = USED(a);
+  mp_digit *pa, *pb;
+  mp_digit padding = ISNEG(a) ? MP_DIGIT_MAX : 0;
+  mp_word w;
+
+  ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+  if (a != b) {
+    if ((res = mp_init_size(b, dig)) != MP_OKAY)
+	return res;
+    SIGN(b) = SIGN(a);
+  } else {
+    if((res = s_mp_pad(b, dig)) != MP_OKAY)
+      return res;
+  }
+
+  for (pa = DIGITS(a), pb = DIGITS(b), w = 0, ix = 0; ix < dig; ix++) {
+    w += (ix == 0);
+    w += (ix < adig) ? ~pa[ix] : padding;
+    pb[ix] = ACCUM(w);
+    w = CARRYOUT(w);
+  }
+
+  USED(b) = dig;
+
+  return MP_OKAY;
+}
+
+mp_err mp_and(mp_int *a, mp_int *b, mp_int *c)
+{
+  mp_err res = MP_OKAY;
+  mp_size ix, extent = 0;
+  mp_digit *pa, *pb, *pc;
+  mp_int tmp_a, tmp_b;
+
+  ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
+
+  if (a == b)
+    return mp_copy(a, c);
+
+  if (ISNEG(a)) {
+    extent = USED(b);
+    mp_init(&tmp_a);
+    if ((res = mp_2comp(a, &tmp_a, extent)) != MP_OKAY)
+	goto out;
+    a = &tmp_a;
+  }
+
+  if (ISNEG(b)) {
+    extent = USED(a);
+    mp_init(&tmp_b);
+    if ((res = mp_2comp(b, &tmp_b, extent)) != MP_OKAY)
+	goto out;
+    b = &tmp_b;
+  }
+
+  if (!extent)
+    extent = MIN(USED(a), USED(b));
+
+  if (c != a && c != b) {
+    if ((res = mp_init_size(c, extent)) != MP_OKAY)
+	goto out;
+  }
+
+  for (pa = DIGITS(a), pb = DIGITS(b), pc = DIGITS(c), ix = 0;
+	 ix < extent; ix++)
+  {
+    pc[ix] = pa[ix] & pb[ix];
+  }
+
+  USED(c) = extent;
+
+  if (ISNEG(a) && ISNEG(b)) {
+    mp_2comp(c, c, extent);
+    SIGN(c) = MP_NEG;
+  }
+
+  s_mp_clamp(c);
+
+out:
+  if (ISNEG(a))
+    mp_clear(&tmp_a);
+
+  if (ISNEG(b))
+    mp_clear(&tmp_b);
+
+  return res;
+}
+
+mp_err mp_or(mp_int *a, mp_int *b, mp_int *c)
+{
+  mp_err res;
+  mp_size ix, extent = 0;
+  mp_digit *pa, *pb, *pc;
+  mp_int tmp_a, tmp_b;
+
+  ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
+
+  extent = MAX(USED(a), USED(b));
+
+  if (a == b)
+    return mp_copy(a, c);
+
+  if (ISNEG(a)) {
+    mp_init(&tmp_a);
+    if ((res = mp_2comp(a, &tmp_a, extent)) != MP_OKAY)
+	goto out;
+    a = &tmp_a;
+  }
+
+  if (ISNEG(b)) {
+    mp_init(&tmp_b);
+    if ((res = mp_2comp(b, &tmp_b, extent)) != MP_OKAY)
+	goto out;
+    b = &tmp_b;
+  }
+
+
+  if (c != a && c != b)
+    res = mp_init_size(c, extent);
+  else
+    res = s_mp_pad(c, extent);
+
+  if (res != MP_OKAY)
+    goto out;
+
+  for (pa = DIGITS(a), pb = DIGITS(b), pc = DIGITS(c), ix = 0;
+	 ix < extent; ix++)
+  {
+    pc[ix] = pa[ix] | pb[ix];
+  }
+
+  USED(c) = extent;
+
+  if (ISNEG(a) || ISNEG(b)) {
+    mp_2comp(c, c, extent);
+    SIGN(c) = MP_NEG;
+  }
+
+  s_mp_clamp(c);
+
+out:
+  if (ISNEG(a))
+    mp_clear(&tmp_a);
+
+  if (ISNEG(b))
+    mp_clear(&tmp_b);
+
+  return res;
+}
+
+mp_err mp_xor(mp_int *a, mp_int *b, mp_int *c)
+{
+  mp_err res;
+  mp_size ix, extent = 0;
+  mp_digit *pa, *pb, *pc;
+  mp_int tmp_a, tmp_b;
+
+  ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
+
+  if (a == b) {
+    mp_zero(c);
+    return MP_OKAY;
+  }
+
+  extent = MAX(USED(a), USED(b));
+
+  if (ISNEG(a)) {
+    mp_init(&tmp_a);
+    if ((res = mp_2comp(a, &tmp_a, extent)) != MP_OKAY)
+	goto out;
+    a = &tmp_a;
+  }
+
+  if (ISNEG(b)) {
+    mp_init(&tmp_b);
+    if ((res = mp_2comp(b, &tmp_b, extent)) != MP_OKAY)
+	goto out;
+    b = &tmp_b;
+  }
+
+
+  if (c != a && c != b)
+    res = mp_init_size(c, extent);
+  else
+    res = s_mp_pad(c, extent);
+
+  if (res != MP_OKAY)
+    goto out;
+
+  for (pa = DIGITS(a), pb = DIGITS(b), pc = DIGITS(c), ix = 0;
+	 ix < extent; ix++)
+  {
+    pc[ix] = pa[ix] ^ pb[ix];
+  }
+
+  USED(c) = extent;
+
+  if (ISNEG(a) ^ ISNEG(b)) {
+    mp_2comp(c, c, extent);
+    SIGN(c) = MP_NEG;
+  }
+
+  s_mp_clamp(c);
+
+out:
+  if (ISNEG(a))
+    mp_clear(&tmp_a);
+
+  if (ISNEG(b))
+    mp_clear(&tmp_b);
+
+  return res;
+}
+
+mp_err mp_comp(mp_int *a, mp_int *b)
+{
+  mp_err res;
+  mp_size ix, dig = USED(a);
+  mp_digit *pa, *pb;
+  mp_int tmp;
+
+  ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+  if (a != b)
+    res = mp_init_size(b, dig);
+  else
+    res = s_mp_pad(b, dig);
+
+  if (res != MP_OKAY)
+    return res;
+
+  if (ISNEG(a)) {
+    mp_init(&tmp);
+    if ((res = mp_2comp(a, &tmp, dig)) != MP_OKAY)
+	return res;
+    a = &tmp;
+  }
+
+  for (pa = DIGITS(a), pb = DIGITS(b), ix = 0; ix < dig; ix++)
+    pb[ix] = ~pa[ix];
+
+  USED(b) = dig;
+
+  if (ISNEG(a)) {
+    mp_clear(&tmp);
+  } else {
+    if ((res = mp_2comp(b, b, dig)) != MP_OKAY)
+	return res;
+    SIGN(b) = MP_NEG;
+  }
+
+  s_mp_clamp(b);
+  return MP_OKAY;
+}
+
+mp_err mp_trunc_comp(mp_int *a, mp_int *b, mp_digit bits)
+{
+  mp_err res;
+  mp_size ix, dig = bits / DIGIT_BIT, rembits = bits % DIGIT_BIT;
+  mp_size adig = USED(a);
+  mp_digit padding = ISNEG(a) ? MP_DIGIT_MAX : 0;
+  int extra = (rembits != 0);
+  mp_digit *pa, *pb;
+  mp_int tmp;
+
+  ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+  if (a != b)
+    res = mp_init_size(b, dig + extra);
+  else
+    res = s_mp_pad(b, dig + extra);
+
+  if (res != MP_OKAY)
+    return res;
+
+  if (ISNEG(a)) {
+    mp_init(&tmp);
+    if ((res = mp_2comp(a, &tmp, dig + extra)) != MP_OKAY)
+	return res;
+    a = &tmp;
+  }
+
+  for (pa = DIGITS(a), pb = DIGITS(b), ix = 0; ix < dig; ix++)
+    pb[ix] = (ix < adig) ? ~pa[ix] : ~padding;
+
+  if (rembits) {
+    mp_digit mask = (MP_DIGIT_MAX >> (DIGIT_BIT - rembits));
+    pb[ix] = (((ix < adig) ? pa[ix] : padding) & mask) ^ mask;
+  }
+
+  USED(b) = dig + extra;
+
+  if (ISNEG(a))
+    mp_clear(&tmp);
+
+  s_mp_clamp(b);
+  return MP_OKAY;
+}
+
+mp_err mp_trunc(mp_int *a, mp_int *b, mp_digit bits)
+{
+  mp_err res;
+  mp_size ix, dig = bits / DIGIT_BIT, rembits = bits % DIGIT_BIT;
+  mp_size adig = USED(a);
+  mp_digit padding = ISNEG(a) ? MP_DIGIT_MAX : 0;
+  int extra = (rembits != 0);
+  mp_digit *pa, *pb;
+  mp_int tmp;
+
+  ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+  if (a != b)
+    res = mp_init_size(b, dig + extra);
+  else
+    res = s_mp_pad(b, dig + extra);
+
+  if (res != MP_OKAY)
+    return res;
+
+  if (ISNEG(a)) {
+    mp_init(&tmp);
+    if ((res = mp_2comp(a, &tmp, dig + extra)) != MP_OKAY)
+	return res;
+    a = &tmp;
+  }
+
+  for (pa = DIGITS(a), pb = DIGITS(b), ix = 0; ix < dig; ix++)
+    pb[ix] = (ix < adig) ? pa[ix] : padding;
+
+  if (rembits) {
+    mp_digit mask = (MP_DIGIT_MAX >> (DIGIT_BIT - rembits));
+    pb[ix] = ((ix < adig) ? pa[ix] : padding) & mask;
+  }
+
+  USED(b) = dig + extra;
+
+  if (ISNEG(a))
+    mp_clear(&tmp);
+
+  s_mp_clamp(b);
+  return MP_OKAY;
+}
+
+mp_err mp_shift(mp_int *a, mp_int *b, int bits)
+{
+  mp_int tmp;
+  mp_err res;
+  int a_neg = ISNEG(a);
+
+  if (bits == 0)
+    return mp_copy(a, b);
+
+  if (a_neg) {
+    mp_size ua = USED(a);
+    mp_init(&tmp);
+    if ((res = mp_2comp(a, &tmp, ua)) != MP_OKAY)
+	return res;
+    SIGN(&tmp) = MP_ZPOS;
+    a = &tmp;
+  }
+
+  if (bits > 0)
+    res = mp_mul_2d(a, bits, b);
+  else
+    res = mp_div_2d(a, -bits, b, NULL);
+
+  if (res != MP_OKAY) {
+    if (a_neg)
+	mp_clear(&tmp);
+    return res;
+  }
+
+  if (a_neg) {
+    int hb, msd;
+    mp_digit *db;
+
+    mp_clear(&tmp);
+
+    msd = USED(b)-1;
+    db = DIGITS(b);
+    hb = s_highest_bit(db[msd]);
+
+    if (hb < DIGIT_BIT)
+	db[msd] |= MP_DIGIT_MAX << hb;
+
+    if ((res = mp_2comp(b, b, USED(b))) != MP_OKAY)
+	return res;
+
+    SIGN(b) = MP_NEG;
+    s_mp_clamp(b);
+  }
+
+  return MP_OKAY;
+}
+
+mp_err mp_bit(mp_int *a, mp_digit bit)
+{
+  mp_int tmp;
+  mp_err res;
+  int a_neg = ISNEG(a);
+  int digit = bit / MP_DIGIT_BIT;
+  mp_digit mask = ((mp_digit) 1 << (bit % MP_DIGIT_BIT));
+
+  if (a_neg) {
+    mp_init(&tmp);
+    if ((res = mp_2comp(a, &tmp, bit + 1)) != MP_OKAY)
+	return res;
+    SIGN(&tmp) = MP_ZPOS;
+    a = &tmp;
+  }
+
+  return (DIGITS(a)[digit] & mask) != 0 ? MP_YES : MP_NO;
+}
+
 mp_err mp_to_double(mp_int *mp, double *d)
 {
   int ix;
diff --git a/mpi/mpi.h b/mpi/mpi.h
index c6136c15..98280247 100644
--- a/mpi/mpi.h
+++ b/mpi/mpi.h
@@ -54,6 +54,7 @@
 
 /* Macros for accessing the mp_int internals           */
 #define  SIGN(MP)     ((MP)->sign)
+#define  ISNEG(MP)    ((MP)->sign == MP_NEG)
 #define  USED(MP)     ((MP)->used)
 #define  ALLOC(MP)    ((MP)->alloc)
 #define  DIGITS(MP)   ((MP)->dp)
@@ -187,6 +188,18 @@ mp_err mp_invmod(mp_int *a, mp_int *m, mp_int *c);
 #endif /* end MP_NUMTH */
 
 /*------------------------------------------------------------------------*/
+/* Bit ops                                                                */
+mp_err mp_2comp(mp_int *a, mp_int *b, mp_size dig); /* peculiar semantics */
+mp_err mp_and(mp_int *a, mp_int *b, mp_int *c);
+mp_err mp_or(mp_int *a, mp_int *b, mp_int *c);
+mp_err mp_xor(mp_int *a, mp_int *b, mp_int *c);
+mp_err mp_comp(mp_int *a, mp_int *b);
+mp_err mp_trunc_comp(mp_int *a, mp_int *b, mp_digit bits);
+mp_err mp_trunc(mp_int *a, mp_int *b, mp_digit bits);
+mp_err mp_shift(mp_int *a, mp_int *b, int bits); /* + left, - right */
+mp_err mp_bit(mp_int *a, mp_digit bit);
+
+/*------------------------------------------------------------------------*/
 /* Conversions                                                            */
 
 mp_err mp_to_double(mp_int *mp, double *d);