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Generic multiplier (Chris Lattner)

This commit is contained in:
steve 2000-04-21 02:30:40 +00:00
parent 37e65614a0
commit d539b0b5fe
1 changed files with 60 additions and 1 deletions
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61
vvm/vvm_mult.cc
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@ -17,16 +17,72 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: vvm_mult.cc,v 1.5 2000/03/22 04:26:41 steve Exp $"
#ident "$Id: vvm_mult.cc,v 1.6 2000/04/21 02:30:40 steve Exp $"
#endif
# include "vvm_gates.h"
# include <assert.h>
static void add_into_result(vpip_bit_t *r, unsigned nr,
const vpip_bit_t *a, unsigned na) {
unsigned idx;
vpip_bit_t carry_bit = St0;
for (idx = 0; idx < nr && idx < na; idx++) {
vpip_bit_t val;
val = B_XOR(B_XOR(a[idx], r[idx]), carry_bit);
carry_bit = B_OR(B_OR(B_AND(a[idx], r[idx]),
B_AND(a[idx], carry_bit)),
B_AND(r[idx], carry_bit));
r[idx] = val;
}
}
static void vvm_binop_mult_generic(vpip_bit_t*r, unsigned nr,
const vpip_bit_t*a, unsigned na,
const vpip_bit_t*b, unsigned nb) {
unsigned idx;
for (idx = 0 ; idx < na ; idx += 1)
if (B_ISXZ(a[idx]))
goto unknown_result;
for (idx = 0 ; idx < nb ; idx += 1)
if (B_ISXZ(b[idx]))
goto unknown_result;
// Start off initialized to 0...
for (idx = 0 ; idx < nr ; idx += 1)
r[idx] = St0;
for (idx = 0; idx < nb && idx < nr; idx++)
if (B_IS1(b[idx]))
add_into_result(r+idx, nr-idx, a, na);
return;
unknown_result:
for (unsigned idx= 0 ; idx < nr ; idx += 1)
r[idx] = StX;
}
void vvm_binop_mult(vpip_bit_t*r, unsigned nr,
const vpip_bit_t*a, unsigned na,
const vpip_bit_t*b, unsigned nb)
{
if (nr > 8*sizeof(unsigned long) ||
na > 8*sizeof(unsigned long) ||
nb > 8*sizeof(unsigned long)) {
// If we can't use the fast routine, default to
// the slow one...
vvm_binop_mult_generic(r, nr, a, na, b, nb);
return;
}
assert(nr <= 8*sizeof(unsigned long));
assert(na <= 8*sizeof(unsigned long));
assert(nb <= 8*sizeof(unsigned long));
@ -130,6 +186,9 @@ void vvm_mult::take_value(unsigned key, vpip_bit_t val)
/*
* $Log: vvm_mult.cc,v $
* Revision 1.6 2000/04/21 02:30:40 steve
* Generic multiplier (Chris Lattner)
*
* Revision 1.5 2000/03/22 04:26:41 steve
* Replace the vpip_bit_t with a typedef and
* define values for all the different bit