4.4.7 Count Leading Zero

Format:

CTLZ

Rb.rq,Rc.wq

! Operate format

Operation:

temp = 0

FOR i FROM 63 DOWN TO 0

IF { Rbv<i> EQ 1 } THEN BREAK temp = temp + 1

END

Rc<6:0> temp<6:0> Rc<63:7> 0

Exceptions:

None

Instruction mnemonics:

CTLZ

Count Leading Zero

Qualifiers:

None

Description:

The number of leading zeros in Rb, starting at the most significant bit position, is written to Rc. Ra must be R31.

Instruction Descriptions 4–31

Page 87
Image 87
Compaq ECQD2KCTE manual Count Leading Zero, Ctlz