s390: Make R2 operand optional in .insn pseudo-mnemonic rr
Makes the R2 operand optional for the .insn rr pseudo-mnemonic in the s390 assembler.
This patch modifies the s390 assembler’s handling of the .insn rr pseudo-mnemonic to make the R2 operand optional. This aligns with the RR instruction format’s optional R2 field. The changes include documentation updates and new test cases for both ESA/390 and z/Architecture operand formats.
- proposer
Makes the R2 operand optional for the .insn rr pseudo-mnemonic and adds corresponding tests and documentation.
“The RR instruction format has an optional R2 field. Make the R2 operand in the .insn pseudo-mnemonic rr optional.”
In Details
This change modifies the gas (GNU Assembler) support for the s390 architecture, specifically concerning the .insn directive and the 'rr' (Register-Register) pseudo-mnemonic. The RR instruction format in s390 architecture permits an optional second register operand (R2). This patch updates the opcode definitions and documentation (s390-opc.c, c-s390.texi) to reflect this optionality for the .insn rr pseudo-mnemonic, enhancing flexibility for assembly code generation, and adds relevant test cases.