Make vector2 multiply more portable.
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steve
parent
e3f300f4c2
commit
60b9121c6c
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@ -16,7 +16,7 @@
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#ident "$Id: vvp_net.cc,v 1.39 2005/06/26 01:57:22 steve Exp $"
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#ident "$Id: vvp_net.cc,v 1.40 2005/06/27 21:13:14 steve Exp $"
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# include "config.h"
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# include "vvp_net.h"
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@ -24,6 +24,7 @@
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# include <stdio.h>
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# include <iostream>
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# include <typeinfo>
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# include <limits.h>
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# include <assert.h>
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/* *** BIT operations *** */
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@ -351,7 +352,7 @@ vvp_vector2_t::vvp_vector2_t(const vvp_vector4_t&that)
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case BIT4_0:
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break;
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case BIT4_1:
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vec_[addr] |= 1 << shift;
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vec_[addr] |= 1UL << shift;
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break;
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default:
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delete[]vec_;
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@ -392,6 +393,63 @@ bool vvp_vector2_t::is_NaN() const
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return wid_ == 0;
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}
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static unsigned long add_carry(unsigned long a, unsigned long b,
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unsigned long&carry)
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{
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unsigned long out = carry;
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carry = 0;
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if ((ULONG_MAX - out) < a)
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carry += 1;
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out += a;
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if ((ULONG_MAX - out) < b)
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carry += 1;
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out += b;
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return out;
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}
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static void multiply_long(unsigned long a, unsigned long b,
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unsigned long&low, unsigned long&high)
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{
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assert(sizeof(unsigned long) %2 == 0);
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const unsigned long word_mask = (1UL << 4UL*sizeof(a)) - 1UL;
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unsigned long tmpa;
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unsigned long tmpb;
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unsigned long res[4];
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tmpa = a & word_mask;
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tmpb = b & word_mask;
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res[0] = tmpa * tmpb;
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res[1] = res[0] >> 4UL*sizeof(unsigned long);
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res[0] &= word_mask;
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tmpa = (a >> 4UL*sizeof(unsigned long)) & word_mask;
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tmpb = b & word_mask;
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res[1] += tmpa * tmpb;
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res[2] = res[1] >> 4UL*sizeof(unsigned long);
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res[1] &= word_mask;
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tmpa = a & word_mask;
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tmpb = (b >> 4UL*sizeof(unsigned long)) & word_mask;
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res[1] += tmpa * tmpb;
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res[2] += res[1] >> 4UL*sizeof(unsigned long);
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res[3] = res[2] >> 4UL*sizeof(unsigned long);
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res[1] &= word_mask;
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res[2] &= word_mask;
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tmpa = (a >> 4UL*sizeof(unsigned long)) & word_mask;
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tmpb = (b >> 4UL*sizeof(unsigned long)) & word_mask;
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res[2] += tmpa * tmpb;
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res[3] += res[2] >> 4UL*sizeof(unsigned long);
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res[2] &= word_mask;
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high = (res[3] << 4UL*sizeof(unsigned long)) | res[2];
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low = (res[1] << 4UL*sizeof(unsigned long)) | res[0];
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}
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/*
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* Multiplication of two vector2 vectors returns a product as wide as
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* the sum of the widths of the input vectors.
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@ -401,31 +459,32 @@ vvp_vector2_t operator * (const vvp_vector2_t&a, const vvp_vector2_t&b)
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const unsigned bits_per_word = 8 * sizeof(a.vec_[0]);
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vvp_vector2_t r (0, a.size() + b.size());
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assert(sizeof(unsigned long long) >= 2*sizeof(a.vec_[0]));
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unsigned long long word_mask = (1ULL << bits_per_word) - 1ULL;
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unsigned awords = (a.wid_ + bits_per_word - 1) / bits_per_word;
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unsigned bwords = (b.wid_ + bits_per_word - 1) / bits_per_word;
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unsigned rwords = (r.wid_ + bits_per_word - 1) / bits_per_word;
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for (unsigned bdx = 0 ; bdx < bwords ; bdx += 1) {
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unsigned long long tmpb = b.vec_[bdx];
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unsigned long tmpb = b.vec_[bdx];
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if (tmpb == 0)
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continue;
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for (unsigned adx = 0 ; adx < awords ; adx += 1) {
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unsigned long long tmpa = a.vec_[adx];
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unsigned long long tmpr = tmpb * tmpa;
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unsigned long tmpa = a.vec_[adx];
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if (tmpa == 0)
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continue;
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unsigned long low, hig;
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multiply_long(tmpa, tmpb, low, hig);
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unsigned long carry = 0;
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for (unsigned sdx = 0
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; (adx+bdx+sdx) < rwords && tmpr > 0
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; (adx+bdx+sdx) < rwords
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; sdx += 1) {
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unsigned long long sum = r.vec_[adx+bdx+sdx];
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sum += tmpr & word_mask;
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r.vec_[adx+bdx+sdx] = sum & word_mask;
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sum >>= bits_per_word;
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tmpr >>= bits_per_word;
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tmpr += sum;
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r.vec_[adx+bdx+sdx] = add_carry(r.vec_[adx+bdx+sdx],
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low, carry);
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low = hig;
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hig = 0;
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}
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}
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}
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@ -1270,6 +1329,9 @@ vvp_bit4_t compare_gtge_signed(const vvp_vector4_t&a,
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/*
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* $Log: vvp_net.cc,v $
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* Revision 1.40 2005/06/27 21:13:14 steve
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* Make vector2 multiply more portable.
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*
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* Revision 1.39 2005/06/26 01:57:22 steve
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* Make bit masks of vector4_t 64bit aware.
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*
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