Make it an 8-qubit adder to make it more difficult

 * quantum ripple-carry adder

 * Cuccaro et al, quant-ph/0410184

 */

// Summit compile:

// Using DM-Sim:

// qcor -linker g++ -qrt nisq adder.qasm -shots 1024 -qpu dm-sim[gpus:4]

OPENQASM 3;

gate ccx a,b,c

}

qubit cin;

qubit a[4];

qubit b[4];

qubit a[8];

qubit b[8];

qubit cout;

bit ans[5];

bit ans[9];

// FIXME: left shift casting to handle different type:

// e.g. i4 vs. i64 (shift value)

// e.g. i8 vs. i64 (shift value)

uint[64] a_in = 1;  

uint[64] b_in = 14; 

uint[64] b_in = 15; 

for i in [0:4] {

for i in [0:8] {

  // FIXME: not able to do this inline....

  bool b1 = bool(a_in[i]);

  bool b2 = bool(b_in[i]);

// add a to b, storing result in b

majority cin, b[0], a[0];

for i in [0: 3] { 

for i in [0: 7] { 

  majority a[i], b[i + 1], a[i + 1]; 

}

cx a[3], cout;

cx a[7], cout;

for i in [2: -1: -1] { 

for i in [6: -1: -1] { 

  unmaj a[i], b[i+1], a[i+1]; 

}

unmaj cin, b[0], a[0];

measure b[0:3] -> ans[0:3];

measure cout[0] -> ans[4];

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measure b[0:7] -> ans[0:7];

measure cout[0] -> ans[8];

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