The behavior of LCR, LNR and LPR have not changed since the introduction of the S/360. Here are some quotes from GA22-6821 "IBM System/360 Principles of Operation:"
For LCR: "An overflow condition occurs when the maximum negative number is complemented; the number remains unchanged." For LNR: "The operation complements positive numbers; negative numbers remain unchanged. The number zero remains unchanged." For LPR: "An overflow condition occurs when the maximum negative number is complemented; the number remains unchanged." The description of the behavior of these instructions as found in SA22-7832 "z/Architecture Principles of Operation" when the operands are both the same size (both are 32-bits or both are 64-bits) matches the S/360 behavior. For LCGFR and LPGFR the first operand is 64-bits and the second operand is 32-bits. These instructions process the maximum 32-bit negative number without recognizing an overflow, i.e., the maximum negative 32-bit number can be complemented and represented correctly as a 64-bit result.
