SUBP Subtract pointer This instruction subtracts the 56-bit address held in the second source register from the 56-bit address held in the first source register, sign-extends the result to 64 bits, and writes the result to the destination register. 1 0 0 1 1 0 1 0 1 1 0 0 0 0 0 0 0 SUBP <Xd>, <Xn|SP>, <Xm|SP> if !IsFeatureImplemented(FEAT_MTE) then UNDEFINED; constant integer d = UInt(Xd); constant integer n = UInt(Xn); constant integer m = UInt(Xm); <Xd> Is the 64-bit name of the general-purpose destination register, encoded in the "Xd" field. <Xn|SP> Is the 64-bit name of the first source general-purpose register or stack pointer, encoded in the "Xn" field. <Xm|SP> Is the 64-bit name of the second general-purpose source register or stack pointer, encoded in the "Xm" field. bits(64) operand1 = if n == 31 then SP[] else X[n, 64]; bits(64) operand2 = if m == 31 then SP[] else X[m, 64]; operand1 = SignExtend(operand1<55:0>, 64); operand2 = NOT(SignExtend(operand2<55:0>, 64)); bits(64) result; (result, -) = AddWithCarry(operand1, operand2, '1'); X[d, 64] = result;