x86-64.net

Instruction

SAHF

Stores bits 7, 6, 4, 2 and 0 of AH into SF, ZF, AF, PF and CF; 64-bit mode needs the LAHF-SAHF feature.

Extensions
Forms
1 (1 Legacy)
Data
Intel XED v2026.08.23

Forms

Every encoding of SAHF that Intel XED knows, one row per XED instruction form (iform). How to read the notation.
InstructionEncodingRequires
SAHF SAHF9ELAHF

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.

CPUID requirements and processors of the XED ISA sets above. Alternatives are separated by “or”; processors follow XED’s chip model, which covers AMD processors up to Zen 2.
ISA setCPUIDProcessors in XED
LAHF

LAHF
CPUID.80000001H:ECX[0] LAHF

Every x86-64 processor in XED’s model

More LAHF-SAHF instructions

Sources

  1. Intel XED v2026.08.23 (commit 0bcb6237345c): forms, encodings, ISA sets, CPUID bits and chip model.
  2. Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 2 (325383-092, June 2026)
  3. Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 1 (253665-093, 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.