Subtract with Borrow-In Arithmetic

Subtract two operands minus a borrow-in from a previous subtract-with-borrow-out, for extended-precision subtraction chains.

Vendor-Neutral Definition

d = a - b - borrow_in (mod 2^width); optionally also produces its own borrow-out for further chaining.
⚠️ Cross-vendor mappings describe semantic relationships and are not guaranteed one-to-one compiler translations.
equivalent with restrictions Both subtract two operands minus an incoming borrow bit, for chaining extended-precision subtraction across multiple words.
Property NVIDIA PTX AMDGPU
Instruction subc v_subb_co_u32, s_subb_u32
ISA Layer Virtual Native
Data Types - u32
Version / Target Introduced PTX ISA 1.2 gfx1100

Important Differences

  • Same CC-register-vs-VCC/SCC convention difference as add-with-carry-out applies here.

Source Evidence

Verification method: documentation