jrcxz

x86-64 and later

Jump if RCX register is 0

jrcxz imm8 {near|short}

JCXZ performs a short jump (with maximum range 128 bytes) if and only if the contents of the CX register is 0. JECXZ does the same thing, but with ECX.

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Forms

Every form of jrcxz the assembler accepts, from NASM's own instruction table. The second column is the processor that introduced the form; a badge marks a form that needs an extension, that is lockable, or that long mode dropped.

FormSinceNotes
jrcxz imm8 {near|short}x86-64long