WEDNESDAY, SEPTEMBER 30, 2026
s390 — Proposed
s390: mvcl operands R1 and R2 must be register pairs
Ensures the mvcl instruction in binutils assembler correctly handles register pair operands.
This patch corrects the binutils assembler’s handling of the s390 ‘mvcl’ instruction. It enforces that the R1 and R2 operands must designate an even-numbered register, which forms an even-odd pair, aligning with the s390 architecture specification. Changes are made to opcode definitions and gas test suites.
In Details
This patch addresses the s390 'mvcl' instruction within the binutils assembler. It corrects the operand validation to ensure that registers R1 and R2, which are interpreted as even-odd pairs, are indeed even-numbered registers as required by the architecture. This impacts the assembler's correctness for specific s390 instructions.