].Nat - Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 3 REV 2.3 Manual

clz
clz — Count Leading Zeros
( ) clz
Format: qp r
1
The number of leading zeros in GR
Description:
An Illegal Operation fault is raised on processor models that do not support the
instruction. CPUID register 4 indicates the presence of the feature on the processor
model. See
details. This capability may also be determined using the test feature (tf) instruction
using the @clz operand.
Operation:
if (PR[qp])
if (!instruction_implemented(CLZ))
illegal_operation_fault();
check_target_register(r
tmp_val = 0;
do {
if (GR[r
} while (tmp_val++ < 63);
GR[r ] = tmp_val;
1
GR[r ].nat = GR[r
1
}
Illegal Operation fault
Interruptions:
3:38
=
r
3
Section 3.1.11, "Processor Identification Registers" on page 1:34
);
1
]{63 - tmp_val} != 0) break;
3

].nat;

3
is placed in GR .
r r
3 1
for
Volume 3: Instruction Reference
I9