From: Andreas Schwab <schwab@linux-m68k.org>
To: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: geert@linux-m68k.org, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com,
martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev,
jolsa@kernel.org, jserv@ccns.ncku.edu.tw, eleanor15x@gmail.com,
marscheng@google.com, linux-kernel@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, bpf@vger.kernel.org,
Daniel Palmer <daniel@thingy.jp>
Subject: Re: [PATCH bpf-next v4 RESEND] m68k, bpf: Add initial BPF JIT compiler support
Date: Wed, 29 Jul 2026 17:33:41 +0200 [thread overview]
Message-ID: <871pclresq.fsf@igel.home> (raw)
In-Reply-To: <20260729002737.1008358-1-visitorckw@gmail.com>
On Jul 29 2026, Kuan-Wei Chiu wrote:
> +static void emit_alu32_k(const struct bpf_insn *insn, struct jit_ctx *ctx)
> +{
> + const s8 *dst = bpf2m68k[insn->dst_reg];
> + const s8 *tmp1 = bpf2m68k[TMP_REG_1];
> + const s8 *tmp2 = bpf2m68k[TMP_REG_2];
> + s8 d_reg;
> +
> + d_reg = bpf_get_reg32(dst[1], tmp1[1], ctx);
> +
> + switch (BPF_OP(insn->code)) {
> + case BPF_MOV:
> + emit_16(ctx, 0x203c | (d_reg << 9)); /* move.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_ADD:
> + emit_16(ctx, 0x0680 | d_reg); /* addi.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_SUB:
> + emit_16(ctx, 0x0480 | d_reg); /* subi.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_AND:
> + emit_16(ctx, 0x0280 | d_reg); /* andi.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_OR:
> + emit_16(ctx, 0x0080 | d_reg); /* ori.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_XOR:
> + emit_16(ctx, 0x0a80 | d_reg); /* eori.l #imm, dst */
> + emit_32(ctx, insn->imm);
> + break;
> + case BPF_LSH:
> + case BPF_RSH:
> + case BPF_ARSH:
> + emit_16(ctx, 0x203c | (tmp2[1] << 9)); /* move.l #imm, count */
> + emit_32(ctx, insn->imm & 0x1f);
That can be moveq. Also, for the other cases, if imm is in the range of
moveq it is worthwhile to load it into a temporary register.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
prev parent reply other threads:[~2026-07-29 15:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-29 0:27 [PATCH bpf-next v4 RESEND] m68k, bpf: Add initial BPF JIT compiler support Kuan-Wei Chiu
2026-07-29 15:33 ` Andreas Schwab [this message]
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