int bu_mulmod (uint32 *c, unsigned int cn, uint32 const *a, unsigned int an, uint32 const *b, unsigned int bn, uint32 const *m, unsigned int mn)
{
unsigned int alen = bu_len(a, an) ;
unsigned int blen = bu_len(b, bn) ;
uint32 x[alen+blen] ;
if (!bu_mul(x, alen+blen, a, alen, b, blen)) return 0 ;
if (!bu_mod(x, alen+blen, m, mn)) return 0 ;
return bu_copy(c, cn, x, mn) ;
}
int bu_divmod (uint32 *q, unsigned int qn, uint32 const *y, unsigned int yn, uint32 const *x, unsigned int xn, uint32 const *m, unsigned int mn)
{
unsigned int ylen = bu_len(y, yn) ;
unsigned int xlen = bu_len(x, xn) ;
unsigned int mlen = bu_len(m, mn) ;
unsigned int n = ylen ;
if (n < xlen) n = xlen ;
if (n < mlen) n = mlen ;
if (!n) return (errno = EDOM, 0) ;
{
uint32 yy[n] ;
uint32 xx[n] ;
uint32 mm[n] ;
bu_gcd(xx, n, x, xlen, m, mlen) ;
if ((xx[0] != 1) || (bu_len(xx, n) != 1)) return (errno = EDOM, 0) ;
bu_copy_internal(yy, y, ylen) ; bu_zero(yy+ylen, n-ylen) ;
bu_copy_internal(xx, x, xlen) ; bu_zero(xx+xlen, n-xlen) ;
bu_copy_internal(mm, m, mlen) ; bu_zero(mm+mlen, n-mlen) ;
bu_divmod_internal(yy, xx, mm, n) ;
return bu_copy(q, qn, yy, n) ;
}
}
void bu_div_internal (uint32 *a, unsigned int an, uint32 const *b, unsigned int bn, uint32 *q, unsigned int qn)
{
unsigned int alen = bu_len(a, an) ;
unsigned int blen = bu_len(b, bn) ;
bu_zero(q, qn) ;
if (alen < blen) return ;
{
uint32 bb[alen + 1] ;
unsigned int i = 1 + ((alen - blen) << 5) ;
bu_zero(bb, alen - blen) ;
bu_copy_internal(bb + alen - blen, b, blen) ;
bb[alen] = 0 ;
while (bu_cmp(a, alen, bb, alen+1) >= 0)
{
bu_slb(bb + alen - blen, blen + 1) ;
i++ ;
}
while (i && (bu_cmp(a, alen, bb, alen+1) < 0))
{
bu_srb(bb, alen + 1) ;
i-- ;
}
while (i--)
{
bu_slb(q, alen - blen + 1) ;
if (bu_cmp(a, alen, bb, alen) >= 0)
{
bu_sub(a, alen, a, alen, bb, alen) ;
q[0] |= 1 ;
}
bu_srb(bb, alen) ;
}
}
}