--- /dev/null
+/* UltraSparc 64 mpn_divrem_1 -- mpn by limb division.
+
+Copyright 1991, 1993, 1994, 1996, 1998, 1999, 2000, 2001, 2003 Free Software
+Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MP Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+#include "mpn/sparc64/sparc64.h"
+
+
+/* 64-bit divisor 32-bit divisor
+ cycles/limb cycles/limb
+ (approx) (approx)
+ integer fraction integer fraction
+ Ultrasparc 2i: 160 160 122 96
+*/
+
+
+/* 32-bit divisors are treated in special case code. This requires 4 mulx
+ per limb instead of 8 in the general case.
+
+ For big endian systems we need HALF_ENDIAN_ADJ included in the src[i]
+ addressing, to get the two halves of each limb read in the correct order.
+ This is kept in an adj variable. Doing that measures about 4 c/l faster
+ than just writing HALF_ENDIAN_ADJ(i) in the integer loop. The latter
+ shouldn't be 6 cycles worth of work, but perhaps it doesn't schedule well
+ (on gcc 3.2.1 at least). The fraction loop doesn't seem affected, but we
+ still use a variable since that ought to work out best. */
+
+mp_limb_t
+mpn_divrem_1 (mp_ptr qp_limbptr, mp_size_t xsize_limbs,
+ mp_srcptr ap_limbptr, mp_size_t size_limbs, mp_limb_t d_limb)
+{
+ mp_size_t total_size_limbs;
+ mp_size_t i;
+
+ ASSERT (xsize_limbs >= 0);
+ ASSERT (size_limbs >= 0);
+ ASSERT (d_limb != 0);
+ /* FIXME: What's the correct overlap rule when xsize!=0? */
+ ASSERT (MPN_SAME_OR_SEPARATE_P (qp_limbptr + xsize_limbs,
+ ap_limbptr, size_limbs));
+
+ total_size_limbs = size_limbs + xsize_limbs;
+ if (UNLIKELY (total_size_limbs == 0))
+ return 0;
+
+ /* udivx is good for total_size==1, and no need to bother checking
+ limb<divisor, since if that's likely the caller should check */
+ if (UNLIKELY (total_size_limbs == 1))
+ {
+ mp_limb_t a, q;
+ a = (LIKELY (size_limbs != 0) ? ap_limbptr[0] : 0);
+ q = a / d_limb;
+ qp_limbptr[0] = q;
+ return a - q*d_limb;
+ }
+
+ if (d_limb <= CNST_LIMB(0xFFFFFFFF))
+ {
+ mp_size_t size, xsize, total_size, adj;
+ unsigned *qp, n1, n0, q, r, nshift, norm_rmask;
+ mp_limb_t dinv_limb;
+ const unsigned *ap;
+ int norm, norm_rshift;
+
+ size = 2 * size_limbs;
+ xsize = 2 * xsize_limbs;
+ total_size = size + xsize;
+
+ ap = (unsigned *) ap_limbptr;
+ qp = (unsigned *) qp_limbptr;
+
+ qp += xsize;
+ r = 0; /* initial remainder */
+
+ if (LIKELY (size != 0))
+ {
+ n1 = ap[size-1 + HALF_ENDIAN_ADJ(1)];
+
+ /* If the length of the source is uniformly distributed, then
+ there's a 50% chance of the high 32-bits being zero, which we
+ can skip. */
+ if (n1 == 0)
+ {
+ n1 = ap[size-2 + HALF_ENDIAN_ADJ(0)];
+ total_size--;
+ size--;
+ ASSERT (size > 0); /* because always even */
+ qp[size + HALF_ENDIAN_ADJ(1)] = 0;
+ }
+
+ /* Skip a division if high < divisor (high quotient 0). Testing
+ here before before normalizing will still skip as often as
+ possible. */
+ if (n1 < d_limb)
+ {
+ r = n1;
+ size--;
+ qp[size + HALF_ENDIAN_ADJ(size)] = 0;
+ total_size--;
+ if (total_size == 0)
+ return r;
+ }
+ }
+
+ count_leading_zeros_32 (norm, d_limb);
+ norm -= 32;
+ d_limb <<= norm;
+ r <<= norm;
+
+ norm_rshift = 32 - norm;
+ norm_rmask = (norm == 0 ? 0 : 0xFFFFFFFF);
+
+ invert_half_limb (dinv_limb, d_limb);
+
+ if (LIKELY (size != 0))
+ {
+ i = size - 1;
+ adj = HALF_ENDIAN_ADJ (i);
+ n1 = ap[i + adj];
+ adj = -adj;
+ r |= ((n1 >> norm_rshift) & norm_rmask);
+ for ( ; i > 0; i--)
+ {
+ n0 = ap[i-1 + adj];
+ adj = -adj;
+ nshift = (n1 << norm) | ((n0 >> norm_rshift) & norm_rmask);
+ udiv_qrnnd_half_preinv (q, r, r, nshift, d_limb, dinv_limb);
+ qp[i + adj] = q;
+ n1 = n0;
+ }
+ nshift = n1 << norm;
+ udiv_qrnnd_half_preinv (q, r, r, nshift, d_limb, dinv_limb);
+ qp[0 + HALF_ENDIAN_ADJ(0)] = q;
+ }
+ qp -= xsize;
+ adj = HALF_ENDIAN_ADJ (0);
+ for (i = xsize-1; i >= 0; i--)
+ {
+ udiv_qrnnd_half_preinv (q, r, r, 0, d_limb, dinv_limb);
+ adj = -adj;
+ qp[i + adj] = q;
+ }
+
+ return r >> norm;
+ }
+ else
+ {
+ mp_srcptr ap;
+ mp_ptr qp;
+ mp_size_t size, xsize, total_size;
+ mp_limb_t d, n1, n0, q, r, dinv, nshift, norm_rmask;
+ int norm, norm_rshift;
+
+ ap = ap_limbptr;
+ qp = qp_limbptr;
+ size = size_limbs;
+ xsize = xsize_limbs;
+ total_size = total_size_limbs;
+ d = d_limb;
+
+ qp += total_size; /* above high limb */
+ r = 0; /* initial remainder */
+
+ if (LIKELY (size != 0))
+ {
+ /* Skip a division if high < divisor (high quotient 0). Testing
+ here before before normalizing will still skip as often as
+ possible. */
+ n1 = ap[size-1];
+ if (n1 < d)
+ {
+ r = n1;
+ *--qp = 0;
+ total_size--;
+ if (total_size == 0)
+ return r;
+ size--;
+ }
+ }
+
+ count_leading_zeros (norm, d);
+ d <<= norm;
+ r <<= norm;
+
+ norm_rshift = GMP_LIMB_BITS - norm;
+ norm_rmask = (norm == 0 ? 0 : ~CNST_LIMB(0));
+
+ invert_limb (dinv, d);
+
+ if (LIKELY (size != 0))
+ {
+ n1 = ap[size-1];
+ r |= ((n1 >> norm_rshift) & norm_rmask);
+ for (i = size-2; i >= 0; i--)
+ {
+ n0 = ap[i];
+ nshift = (n1 << norm) | ((n0 >> norm_rshift) & norm_rmask);
+ udiv_qrnnd_preinv (q, r, r, nshift, d, dinv);
+ *--qp = q;
+ n1 = n0;
+ }
+ nshift = n1 << norm;
+ udiv_qrnnd_preinv (q, r, r, nshift, d, dinv);
+ *--qp = q;
+ }
+ for (i = 0; i < xsize; i++)
+ {
+ udiv_qrnnd_preinv (q, r, r, CNST_LIMB(0), d, dinv);
+ *--qp = q;
+ }
+ return r >> norm;
+ }
+}
projects / msp430-gcc.git / blobdiff