is_string_insn(9)

💖 is_string_insn(9) 💖

okay so bestie, welcome to the kernel API manual, section 9 — this one's called is_string_insn, and it's literally the little vibe-check function that tells you if an instruction is a string instruction. that's the whole gig. 🎀

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✨ NAME ✨

is_string_insn — Determine if instruction is a string instruction

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🌸 SYNOPSIS 🌸

bool is_string_insn (struct insn *insn );

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🦋 ARGUMENTS 🦋

• insn — the Instruction containing the opcode to inspect 👀 that's the thing you're passing in for judgement, bestie.

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💅 DESCRIPTION 💅

so it returns true if the instruction — the one determined by the opcode — is any of the string instructions as defined in the Intel Software Development manual. and it returns False otherwise. no cap, that's it. it's giving simple, it's giving useful, it's giving "i just need to know if this is a string instruction or not." ✨

fr fr: the answer is based on the opcode, and the source of truth is the Intel Software Development manual — not vibes.

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🌈 SEE ALSO 🌈

• Kernel file ./arch/x86/lib/insn-eval.c — and honestly, the whole insn-eval bestie squad lives here:
• insn_has_rep_prefix(9)
• get_seg_reg_override_idx(9)
• check_seg_overrides(9)
• resolve_default_seg(9)
• resolve_seg_reg(9)
• get_segment_selector(9)
• get_reg_offset_16(9)
• get_desc(9)
• insn_get_seg_base(9)
• get_seg_limit(9)
• insn_get_code_seg_params(9)
• insn_get_modrm_rm_off(9)
• insn_get_modrm_reg_off(9)
• insn_get_modrm_reg_ptr(9)
• get_seg_base_limit(9)
• get_eff_addr_reg(9)
• get_eff_addr_modrm(9)
• get_eff_addr_modrm_16(9)
• get_eff_addr_sib(9)
• get_addr_ref_16(9)
• get_addr_ref_32(9)
• get_addr_ref_64(9)
• insn_get_addr_ref(9)
• insn_fetch_from_user(9)
• insn_fetch_from_user_inatomic(9)
• insn_decode_from_regs(9)
• insn_decode_mmio(9)

like, that's an entire friend group right there and they all ate. go read them, iykyk 🫶

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and that's the page, bestie 🧚 — straight out of the Kernel API Manual, filed under ./arch/x86/lib, dated October 2026 ✨💜 go off and inspect those opcodes, you icon 👑