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Added recursive bit-blasting of a carry-lookahead adder.

This commit is contained in:
Alan Mishchenko 2016-02-06 12:08:23 -08:00
parent 355865e81b
commit 0224039132
1 changed files with 51 additions and 0 deletions
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51
src/base/wlc/wlcBlast.c
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@ -274,6 +274,56 @@ void Wlc_BlastSubtract( Gia_Man_t * pNew, int * pAdd0, int * pAdd1, int nBits )
for ( b = 0; b < nBits; b++ )
Wlc_BlastFullAdder( pNew, pAdd0[b], Abc_LitNot(pAdd1[b]), Carry, &Carry, &pAdd0[b] );
}
void Wlc_BlastAdderCLA_one( Gia_Man_t * pNew, int * pGen, int * pPro, int * pCar, int * pGen1, int * pPro1, int * pCar1 )
{
int Temp = Gia_ManHashAnd( pNew, pGen[0], pPro[1] );
*pPro1 = Gia_ManHashAnd( pNew, pPro[0], pPro[1] );
*pGen1 = Gia_ManHashOr( pNew, Gia_ManHashOr(pNew, pGen[1], Temp), Gia_ManHashAnd(pNew, *pPro1, pCar[0]) );
*pCar1 = Gia_ManHashOr( pNew, pGen[0], Gia_ManHashAnd(pNew, pPro[0], pCar[0]) );
}
void Wlc_BlastAdderCLA_rec( Gia_Man_t * pNew, int * pGen, int * pPro, int * pCar, int nBits, int * pGen1, int * pPro1 )
{
if ( nBits == 2 )
Wlc_BlastAdderCLA_one( pNew, pGen, pPro, pCar, pGen1, pPro1, pCar+1 ); // returns *pGen1, *pPro1, pCar[1]
else
{
int pGen2[2], pPro2[2];
assert( nBits % 2 == 0 );
// call recursively
Wlc_BlastAdderCLA_rec( pNew, pGen, pPro, pCar, nBits/2, pGen2, pPro2 );
pCar[nBits/2] = *pGen2;
Wlc_BlastAdderCLA_rec( pNew, pGen+nBits/2, pPro+nBits/2, pCar+nBits/2, nBits/2, pGen2+1, pPro2+1 );
// create structure
Wlc_BlastAdderCLA_one( pNew, pGen2, pPro2, pCar, pGen1, pPro1, pCar+nBits/2 ); // returns *pGen1, *pPro1, pCar[nBits/2]
}
}
void Wlc_BlastAdderCLA( Gia_Man_t * pNew, int * pAdd0, int * pAdd1, int nBits ) // result is in pAdd0
{
int * pGen = ABC_CALLOC( int, nBits );
int * pPro = ABC_CALLOC( int, nBits );
int * pCar = ABC_CALLOC( int, nBits+1 );
int b, Gen, Pro;
if ( nBits == 1 )
{
int Carry = 0;
Wlc_BlastFullAdder( pNew, pAdd0[0], pAdd1[0], Carry, &Carry, &pAdd0[0] );
return;
}
assert( nBits >= 2 );
pCar[0] = 0;
for ( b = 0; b < nBits; b++ )
{
pGen[b] = Gia_ManHashAnd(pNew, pAdd0[b], pAdd1[b]);
pPro[b] = Gia_ManHashXor(pNew, pAdd0[b], pAdd1[b]);
}
Wlc_BlastAdderCLA_rec( pNew, pGen, pPro, pCar, nBits, &Gen, &Pro );
for ( b = 0; b < nBits; b++ )
pAdd0[b] = Gia_ManHashXor(pNew, pPro[b], pCar[b]);
ABC_FREE(pGen);
ABC_FREE(pPro);
ABC_FREE(pCar);
}
void Wlc_BlastMinus( Gia_Man_t * pNew, int * pNum, int nNum, Vec_Int_t * vRes )
{
int * pRes = Wlc_VecCopy( vRes, pNum, nNum );
@ -887,6 +937,7 @@ Gia_Man_t * Wlc_NtkBitBlast( Wlc_Ntk_t * p, Vec_Int_t * vBoxIds )
int * pArg1 = Wlc_VecLoadFanins( vTemp1, pFans1, nRange1, nRangeMax, Wlc_ObjIsSignedFanin01(p, pObj) );
if ( pObj->Type == WLC_OBJ_ARI_ADD )
Wlc_BlastAdder( pNew, pArg0, pArg1, nRange ); // result is in pFan0 (vRes)
// Wlc_BlastAdderCLA( pNew, pArg0, pArg1, nRange ); // result is in pFan0 (vRes)
else
Wlc_BlastSubtract( pNew, pArg0, pArg1, nRange ); // result is in pFan0 (vRes)
Vec_IntShrink( vRes, nRange );