SBCS Subtract with carry, setting flags This instruction subtracts a register value and the value of NOT (Carry flag) from a register value, and writes the result to the destination register. It updates the condition flags based on the result. If PSTATE.DIT is 1: The execution time of this instruction is independent of: The values of the data supplied in any of its registers. The values of the NZCV flags. The response of this instruction to asynchronous exceptions does not vary based on: The values of the data supplied in any of its registers. The values of the NZCV flags. This instruction is used by the alias NGCS Rn == '11111' See below for details of when the alias is preferred. 1 1 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 SBCS <Wd>, <Wn>, <Wm> 1 SBCS <Xd>, <Xn>, <Xm> constant integer d = UInt(Rd); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer datasize = 32 << UInt(sf); <Wd> Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field. <Wn> Is the 32-bit name of the first general-purpose source register, encoded in the "Rn" field. <Wm> Is the 32-bit name of the second general-purpose source register, encoded in the "Rm" field. <Xd> Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field. <Xn> Is the 64-bit name of the first general-purpose source register, encoded in the "Rn" field. <Xm> Is the 64-bit name of the second general-purpose source register, encoded in the "Rm" field. Alias Conditions constant bits(datasize) operand1 = X[n, datasize]; constant bits(datasize) operand2 = NOT(X[m, datasize]); bits(datasize) result; bits(4) nzcv; (result, nzcv) = AddWithCarry(operand1, operand2, PSTATE.C); X[d, datasize] = result; PSTATE.<N,Z,C,V> = nzcv;