Sign extends eax into rax, so that a 32 bit signed value read from memory or returned by a syscall can be used in 64 bit arithmetic. It takes no operands and touches no other register. movsxd rax, eax does the same thing in two more bytes.
cdqe
x86-64 and laterConvert Doubleword to Quadword
cdqeLoading...
Forms
Every form of cdqe 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.
| Form | Since | Notes |
|---|---|---|
| cdqe | x86-64 | long |