binutils Newspaper
OCTOBER 12, 2026
s390 — Proposed

s390: Add test for .insn pseudo-mnemonic rsi

Adds gas test cases and documentation for the .insn rsi pseudo-mnemonic on s390.

This patch introduces test cases and documentation for the .insn rsi pseudo-mnemonic in the s390 GNU Assembler (gas). It addresses a historical discrepancy in operand order by documenting it and adding corresponding tests to ensure accurate assembly and disassembly.

In the Thread 1 participant
  1. Jens Remus <jremus@linux.ibm.com> proposer

    Submits patches to add test cases and documentation for the .insn rsi pseudo-mnemonic in the s390 gas assembler, noting a historical operand order difference.

    “For historic reasons the .insn rsi pseudo-mnemonic operand order differs from the field index order. Document that.”

In Details

This patch adds test cases and documentation for the '.insn rsi' pseudo-mnemonic in the s390 GNU Assembler (gas). It updates documentation to reflect the historical operand order for RSI and adds corresponding tests to the esa-operands and zarch-operands test suites.

For Context
.insn
A GNU Assembler directive that allows embedding raw machine instructions or pseudo-mnemonics, useful for testing or specific instruction generation.
pseudo-mnemonic
An assembly language construct that resembles a machine instruction but is processed by the assembler to generate one or more actual machine instructions or to represent a complex instruction format.
Filed Under: s390gastestsdocumentationassembler