### Description
Count the number of one bits in a and place the resulting population count in 32-bit
destination register d. Operand a has the instruction type and destination d has type
.u32.
### Syntax
```
popc.type d, a;
.type = { .b32, .b64 };
```
### Semantics
```
.u32 d = 0;
while (a != 0) {
if (a & 0x1) d++;
a = a >> 1;
}
```
### Examples
```
popc.b32 d, a;
popc.b64 cnt, X; // cnt is .u32
```