s390: Add .insn pseudo-mnemonic i
Adds support for the .insn i pseudo-mnemonic in the s390 assembler and updates the svc instruction to use the new I_U format.
This patch introduces the ‘.insn i’ pseudo-mnemonic for the s390 architecture in the GNU Assembler. It defines the I_U instruction format, removes the deprecated RR_U0 format, and modifies the ‘svc’ instruction to utilize the new I_U format, aligning it with the z/Architecture Principles of Operation. Test cases are added for both ESA/390 and z/Architecture.
- proposer
Adds the .insn i pseudo-mnemonic, defines the I_U instruction format, and updates the svc instruction to use it, along with adding test cases.
In Details
This patch integrates the 'I' instruction format and its corresponding '.insn i' pseudo-mnemonic into the s390 assembler. It updates the opcode definitions to include the I_U format, removes an older RR_U0 format, and modifies the svc instruction to conform to the new format as per the z/Architecture specification. Test coverage is expanded for both ESA/390 and z/Architecture.
- .insn
- An assembler directive that allows direct insertion of machine instructions using their opcode and operands, often used for undefined or specialized instructions.
- pseudo-mnemonic
- A symbolic name used in assembly language that corresponds to a machine instruction or a sequence of instructions, often used for convenience or to represent complex operations.
- svc instruction
- Supervisor Call instruction, used to transfer control from user mode to the operating system's supervisor mode.
- I_U format
- A specific s390 instruction format used for instructions like '.insn i', characterized by an opcode and a single immediate operand.