Instruction
CDQ
Sign-extends EAX into EDX:EAX, filling EDX with the sign bit of EAX, typically before a 32-bit IDIV (AT&T cltd).
- Extensions
- Forms
- 1 (1 Legacy)
- Data
- Intel XED v2026.08.23
Forms
| Instruction | Encoding | Requires |
|---|---|---|
CDQ
CDQ | 99 | Base instruction set |
CPUID and processors
Each form belongs to an XED ISA set. A form can be used when the processor reports every CPUID bit of one of its ISA set's alternatives.
| ISA set | CPUID | Processors in XED |
|---|---|---|
I386 | No CPUID bit: part of the base instruction set. | Every x86-64 processor in XED’s model |
More General-purpose instructions
Sources
- Intel XED v2026.08.23 (commit
0bcb6237345c): forms, encodings, ISA sets, CPUID bits and chip model. - Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 2 (325383-092, June 2026)
- Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 2 (325383-093, September 2026)
The tables are derived from Intel XED, Copyright Intel Corporation, licensed under the Apache License 2.0; x86-64.net converted and reformatted them. The text is our own.