s390: Correct documentation of instruction formats
Corrects the documentation for s390 RIS and RSI instruction formats, adjusting bit positions and instruction lengths.
This patch corrects inaccuracies in the GNU Assembler’s documentation for the s390 architecture’s RIS and RSI instruction formats. Specifically, it adjusts the bit position of the second opcode field in the RIS format to bits 40-47 and corrects the instruction length of the RSI format to 4 bytes, ensuring documentation aligns with the IBM z/Architecture Principles of Operation.
- proposer
Corrects the bit field definition for the RIS instruction format and the byte length for the RSI instruction format in the documentation.
In Details
This patch rectifies documentation errors in gas/doc/c-s390.texi concerning s390 instruction formats. It corrects the bit positioning for the secondary opcode in the RIS format (bits 40-47 instead of 36-47) and sets the correct byte length for the RSI format to 4 bytes, based on the 'IBM z/Architecture Principles of Operation' documentation.
- RIS format
- A s390 instruction format that uses a specific bit layout for its opcode and operands.
- RSI format
- A s390 instruction format that includes register and immediate operands, with a specified byte length.
- bit position
- The specific location (bit index) of a field within a machine instruction's binary representation.