28.2.21 __builtin_ff1l, __builtin_ff1r

Description

Finds first one (1) from left (Msb) or right (Lsb) in value. An example:

 int32_t result, value;
 result = __builtin_ff1l(value);

might generate:

ff1l w4, w5

Prototype

int32_t __builtin_ff1l(int32_t value);
int32_t __builtin_ff1r(int32_t value);

Argument

value – Integer number to check for first 1.

Return Value

Returns a literal value sign extended to represent the number of bits to shift left or right.

Machine Instruction

ff1l
fflr

Error Messages

None.