diff options
Diffstat (limited to 'mpi/mpi-bit.c')
| -rw-r--r-- | mpi/mpi-bit.c | 56 |
1 files changed, 51 insertions, 5 deletions
diff --git a/mpi/mpi-bit.c b/mpi/mpi-bit.c index 9bde9f0fb..1eb63a02d 100644 --- a/mpi/mpi-bit.c +++ b/mpi/mpi-bit.c @@ -23,16 +23,29 @@ #include <stdlib.h> #include <assert.h> #include "mpi-internal.h" +#include "longlong.h" /**************** * Return the number of bits in A. - * fixme: we should not count leading zero bits */ unsigned mpi_get_nbits( MPI a ) { - return a->nlimbs * BITS_PER_MPI_LIMB; + unsigned nbits; + unsigned n, count = 0; + + if( a->nlimbs ) { + mpi_limb_t alimb = a->d[a->nlimbs-1]; + if( alimb ) + count_leading_zeros( n, alimb ); + else + n = BITS_PER_MPI_LIMB; + n = BITS_PER_MPI_LIMB - n + (a->nlimbs-1) * BITS_PER_MPI_LIMB; + } + else + n = 0; + return n; } @@ -75,6 +88,28 @@ mpi_set_bit( MPI a, unsigned n ) } /**************** + * Set bit N of A. and clear all bits above + */ +void +mpi_set_highbit( MPI a, unsigned n ) +{ + unsigned limbno, bitno; + + limbno = n / BITS_PER_MPI_LIMB; + bitno = n % BITS_PER_MPI_LIMB; + + if( limbno >= a->nlimbs ) { /* resize */ + if( a->alloced >= limbno ) + mpi_resize(a, limbno+1 ); + a->nlimbs = limbno+1; + } + a->d[limbno] |= (1<<bitno); + for( bitno++; bitno < BITS_PER_MPI_LIMB; bitno++ ) + a->d[limbno] &= ~(1 << bitno); + a->nlimbs = limbno+1; +} + +/**************** * Clear bit N of A. */ void @@ -109,7 +144,7 @@ mpi_set_bytes( MPI a, unsigned nbits, byte (*fnc)(int), int opaque ) a->nlimbs = nlimbs2; for(n=0; n < nlimbs; n++ ) { p = (byte*)(a->d+n); - #ifdef HAVE_LITTLE_ENDIAN + #ifdef LITTLE_ENDIAN_HOST for(i=0; i < BYTES_PER_MPI_LIMB; i++ ) p[i] = fnc(opaque); #else @@ -119,7 +154,18 @@ mpi_set_bytes( MPI a, unsigned nbits, byte (*fnc)(int), int opaque ) } if( xbytes ) { p = (byte*)(a->d+n); - #ifdef HAVE_LITTLE_ENDIAN + #ifdef LITTLE_ENDIAN_HOST + for(i=0; i < xbytes; i++ ) + p[i] = fnc(opaque); + #else + for(i=xbytes-1; i>=0; i-- ) + p[i] = fnc(opaque); + #endif + } + #if 0 /* fixme: set complete random byte and clear out the unwanted ones*/ + if( xbits ) { + p = (byte*)(a->d+n); + #ifdef LITTLE_ENDIAN_HOST for(i=0; i < xbytes; i++ ) p[i] = fnc(opaque); #else @@ -127,7 +173,7 @@ mpi_set_bytes( MPI a, unsigned nbits, byte (*fnc)(int), int opaque ) p[i] = fnc(opaque); #endif } - assert(!xbits); + #endif } /**************** |