5.11 Logical and Bit Manipulation Functions

These functions behave as if twos complement arithmetic were used (although sign-magnitude is the actual implementation). The least significant bit is number 0.

Function: void mpz_and (mpz_t rop, const mpz_t op1, const mpz_t op2)

Set rop to op1 bitwise-and op2.

Function: void mpz_ior (mpz_t rop, const mpz_t op1, const mpz_t op2)

Set rop to op1 bitwise inclusive-or op2.

Function: void mpz_xor (mpz_t rop, const mpz_t op1, const mpz_t op2)

Set rop to op1 bitwise exclusive-or op2.

Function: void mpz_com (mpz_t rop, const mpz_t op)

Set rop to the one’s complement of op.

Function: mp_bitcnt_t mpz_popcount (const mpz_t op)

If op>=0, return the population count of op, which is the number of 1 bits in the binary representation. If op<0, the number of 1s is infinite, and the return value is the largest possible mp_bitcnt_t.

Function: mp_bitcnt_t mpz_hamdist (const mpz_t op1, const mpz_t op2)

If op1 and op2 are both >=0 or both <0, return the hamming distance between the two operands, which is the number of bit positions where op1 and op2 have different bit values. If one operand is >=0 and the other <0 then the number of bits different is infinite, and the return value is the largest possible mp_bitcnt_t.

Function: mp_bitcnt_t mpz_scan0 (const mpz_t op, mp_bitcnt_t starting_bit)

Function: mp_bitcnt_t mpz_scan1 (const mpz_t op, mp_bitcnt_t starting_bit)

Scan op, starting from bit starting_bit, towards more significant bits, until the first 0 or 1 bit (respectively) is found. Return the index of the found bit.

If the bit at starting_bit is already what’s sought, then starting_bit is returned.

If there’s no bit found, then the largest possible mp_bitcnt_t is returned. This will happen in mpz_scan0 past the end of a negative number, or mpz_scan1 past the end of a nonnegative number.

Function: void mpz_setbit (mpz_t rop, mp_bitcnt_t bit_index)

Set bit bit_index in rop.

Function: void mpz_clrbit (mpz_t rop, mp_bitcnt_t bit_index)

Clear bit bit_index in rop.

Function: void mpz_combit (mpz_t rop, mp_bitcnt_t bit_index)

Complement bit bit_index in rop.

Function: int mpz_tstbit (const mpz_t op, mp_bitcnt_t bit_index)

Test bit bit_index in op and return 0 or 1 accordingly.