Subtract with Borrow-Out Arithmetic

Subtract two operands and record the borrow-out for use by a subsequent extended-precision subtract.

Vendor-Neutral Definition

d = a - b (mod 2^width); borrow_out_flag = 1 if the true difference underflowed, else 0.
⚠️ Cross-vendor mappings describe semantic relationships and are not guaranteed one-to-one compiler translations.
equivalent with restrictions Both subtract two operands and record whether the result underflowed, for use in a following extended-precision subtract.
Property NVIDIA PTX AMDGPU
Instruction sub.cc v_sub_co_u32, s_sub_u32
ISA Layer Virtual Native
Data Types - u32
Version / Target Introduced PTX ISA 1.2 gfx1100, gfx942/gfx1100

Important Differences

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

Source Evidence

Verification method: documentation