#!/bin/sh

# A tool to disassemble one riscv64 instruction.

if [ "$#" -ne 1 ]; then
  echo "Usage:"
  echo "  $ riscv64-disasm 0x60469613"
  echo "0:   60469613                sext.b  a2,a3"
  echo
  echo "  The prefix \"0x\" is optional. Compressed instructions are also allowed."
  exit
fi

TEMP="$(mktemp)"
INSN="0x$(echo $1 | sed -e "s/^0x//")"

echo ".text" > "$TEMP.S"
echo ".word $INSN" >> "$TEMP.S"

# riscv objdump only understands extensions in elf files, so we cannot
# disassemble a pure binary.
# Add needed extensions to march when required.
riscv64-linux-gnu-as -march=rv64gc_zba_zbb_zbs_v -o "$TEMP.o" "$TEMP.S"
# Assembler marks .word bytes as data pool ("$d"), and objdump doesn't
# disassemble such instructions. Strip symbols to force instruction disassembly.
riscv64-linux-gnu-strip "$TEMP.o"
riscv64-linux-gnu-objdump -M numeric -d "$TEMP.o" | sed '0,/<.text>/d'

rm "$TEMP.S" "$TEMP.o"