v_cmpx_lt_u64 GPU Native ISA AMD Vector
V CMPX LT U64 Comparison
v_cmpx_lt_u64
Set the per-lane condition code to 1 iff the first input is less than the second input.
Encoding
Verified bit-level encoding data is not yet available for this instruction.
The instruction-format classification below (VOPC)
is well-documented and stable; exact per-target opcode/field bit positions have not
yet been imported from a verified source.
Operands
Operand details have not yet been curated for this instruction.
GFX Target Compatibility
| Target | Support |
|---|---|
| gfx1100 | ✅ Supported |
Related
More in Comparison
Reference
AMDGPU / GFX ISA
Description
Set the per-lane condition code to 1 iff the first input is less than the second input. Store the result into the EXEC mask and to VCC or a scalar register.
Semantics
EXEC.u64[laneId] = D0.u64[laneId] = S0.u64 < S1.u64;
// D0 = VCC in VOPC encoding.
Example
v_cmpx_lt_u64 -1, v[2:3]A real instruction accepted by the LLVM assembler, taken verbatim from LLVM's own AMDGPU MC test suite (gfx11). Not from an AMD document, and not authored here.
Sources
- User Guide for AMDGPU Backend ↗ - LLVM Project
-
"AMD Instinct MI300" Instruction Set Architecture: Reference Guide ↗
- Advanced Micro Devices, Inc.
Reference Guide, page 260. - LLVM MC assembler tests for AMDGPU (gfx11) ↗ - LLVM Project