u32 aarch64_insn_gen_load_store_pair()

in lib/insn.c [507:569]

• 57 lines of code
• 11 McCabe index (conditional complexity)

u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
				     enum aarch64_insn_register reg2,
				     enum aarch64_insn_register base,
				     int offset,
				     enum aarch64_insn_variant variant,
				     enum aarch64_insn_ldst_type type)
{
	u32 insn;
	int shift;

	switch (type) {
	case AARCH64_INSN_LDST_LOAD_PAIR_PRE_INDEX:
		insn = aarch64_insn_get_ldp_pre_value();
		break;
	case AARCH64_INSN_LDST_STORE_PAIR_PRE_INDEX:
		insn = aarch64_insn_get_stp_pre_value();
		break;
	case AARCH64_INSN_LDST_LOAD_PAIR_POST_INDEX:
		insn = aarch64_insn_get_ldp_post_value();
		break;
	case AARCH64_INSN_LDST_STORE_PAIR_POST_INDEX:
		insn = aarch64_insn_get_stp_post_value();
		break;
	default:
		pr_err("%s: unknown load/store encoding %d\n", __func__, type);
		return AARCH64_BREAK_FAULT;
	}

	switch (variant) {
	case AARCH64_INSN_VARIANT_32BIT:
		if ((offset & 0x3) || (offset < -256) || (offset > 252)) {
			pr_err("%s: offset must be multiples of 4 in the range of [-256, 252] %d\n",
			       __func__, offset);
			return AARCH64_BREAK_FAULT;
		}
		shift = 2;
		break;
	case AARCH64_INSN_VARIANT_64BIT:
		if ((offset & 0x7) || (offset < -512) || (offset > 504)) {
			pr_err("%s: offset must be multiples of 8 in the range of [-512, 504] %d\n",
			       __func__, offset);
			return AARCH64_BREAK_FAULT;
		}
		shift = 3;
		insn |= AARCH64_INSN_SF_BIT;
		break;
	default:
		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
		return AARCH64_BREAK_FAULT;
	}

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
					    reg1);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT2, insn,
					    reg2);

	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
					    base);

	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_7, insn,
					     offset >> shift);
}