Bit-Field Insert Bit Manipulation

Insert a contiguous bit field from one operand into another at a given position.

Vendor-Neutral Definition

d = (b & ~mask) | ((a << pos) & mask), where mask covers len bits starting at pos.
⚠️ Cross-vendor mappings describe semantic relationships and are not guaranteed one-to-one compiler translations.
equivalent with restrictions Both insert a bit field from one operand into another at a given position; operand order and count differ.
Property NVIDIA PTX AMDGPU
Instruction bfi v_bfi_b32
ISA Layer Virtual Native
Data Types - b32
Version / Target Introduced PTX ISA 2.0 gfx1100

Important Differences

  • AMDGPU's v_bfi_b32 is documented as a generic (mask, a, b) select: D0 = (S0 & S1) | (~S0 & S2) - functionally a bit-select, not phrased in terms of a start position and length the way PTX's bfi is; the same result is achieved by constructing an appropriate mask operand.

Source Evidence

Verification method: documentation