All instructionsx86-64Compare

SETNB

/ SETAE, SETNC

Set byte if unsigned above or equal

Test CF = 0; write one when true, otherwise zero.

x86-64

Instruction forms

1 in this sample
FormBitsRequiresEncoding
SETNB r88x86-640F 93 /r
8 bits

Operation

Pseudo-C · selected form
dst_byte = (CF = 0) ? 1 : 0

Simplified pseudocode for the selected form.

Exact upstream semantics

Standard variant

Source: intel/SETcc-Set-Byte-on-Condition.xml/0

let result := if Condition_Holds(cond) then 1[7:0] else 0[7:0];

Parameterized by register and element size; from the pinned upstream definition.

What to watch for

  • REX prefixes exclude AH/BH/CH/DH destinations.

Architectural details

Flags
Reads CF = 0; leaves RFLAGS unchanged.
Destination
Writes one byte; all other bits of the destination register are preserved.
Encoding
0F 93 /r
Operands
  • r8write · 8 bits
Coverage
Selected register destinations only; memory and 16-bit conditional-move forms are outside this selection.
Conditions
  • unsigned above or equal: CF = 0
Exception information & execution requirements
  • #UD

Imported exceptions are checks exposed by this XML form; memory, stack, instruction-fetch and called architectural helpers can introduce additional faults.

Feature availability alone does not guarantee execution: OS state and execution-level controls also apply. Use the linked architecture documentation for the full exception conditions.

Performance measurements are not included in this preview. Latency and throughput depend on the exact form and microarchitecture. Measured data on uops.info ↗

Sources & provenance

Technical fields are imported from pinned upstream files. Explanations and explorer behavior are maintained separately.

Intel · SETcc-Set-Byte-on-Condition.xml
Revision
4ebe7f0ac1bd00f46244c49bb72c503ce368def7
SHA-256
e70cd9cfa44dd8dbf545c67a6a7f089d2f191efdc7bde6313738cb8f23a2828d
Terms
Intel SDM terms; see License.md
View pinned upstream file ↗

Intel sources are a documentation preview. Arm ACLE mappings are adapted under CC BY-SA 4.0 with an additional patent license. Arm MRS encoding data is distributed under BSD-3-Clause. © Arm Limited and contributors. Coverage and attribution.