4.3.7. CLZ

Count Leading Zeroes.

Syntax

CLZ{cond} Rd, Rm

where:

cond

is an optional condition code (see Conditional execution).

Rd

is the ARM register for the result. Rd mustnot be r15.

Rm

is the operand register.

Usage

The CLZ instruction counts the number of leading zeroes in the value in Rm and returns the result in Rd. The result value is 32 if no bits are set in the source register, and zero if bit 31 is set.

Condition flags

This instruction does not affect the flags.

Architectures

This instruction is available in ARM architecture versions 5 and above.

Examples

    CLZ     r4,r9
    CLZNE   r2,r3
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