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1/*
2 * Copyright (c) 2021 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16.type ExecuteImplStub, @function
17.global ExecuteImplStub
18.balign 16
19ExecuteImplStub:
20    .cfi_startproc
21    .cfi_def_cfa rsp, __SIZEOF_POINTER__
22    // arg0: %rdi: thread
23    // arg1: %rsi: PC
24    // arg2: %rdx: I-frame
25    // arg3: %rcx: impl
26    pushq %rbx
27    .cfi_adjust_cfa_offset 8
28    .cfi_rel_offset %rbx, 0
29
30     /*
31     * using CFI opcode to get the interpreter pc from
32     * saved register with offset.
33     *
34     * 0x16 dw_cfa_val_expression
35     * 0    tempreg
36     * 0x09 size of expression
37     * 0x0c dw_op_const4u
38     * 0x41, 0x45, 0x58, 0x31 magic = "aex1"
39     * 0x13 dw_op_drop
40     * 0x92 dw_op_bregx
41     * 0x03   the register which store interpreter pc
42     * 0    offset
43     */
44    .cfi_escape 0x16, 0, 0x09, 0x0C, 0x41, 0x45, 0x58, 0x31, 0x13, 0x92, 0x03, 0
45
46    movq %rsi, %rbx
47    call *%rcx
48
49    popq %rbx
50    .cfi_adjust_cfa_offset -8
51    .cfi_restore %rbx
52    ret
53    .cfi_endproc
54
55