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1/*
2 * Copyright (c) 2023-2024 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#include "runtime/fibers/arch/asm_macros.h"
17#include "runtime/fibers/arch/arm/context_layout.h"
18
19#define GPR_O(reg) FCTX_GPR_OFFSET_BYTES_ ## reg
20#define FP_O(reg) FCTX_FP_OFFSET_BYTES_ ## reg
21#include "runtime/fibers/arch/arm/helpers.S"
22
23/**
24 * arguments:
25 * r0: uint8_t* ctx_memory_from
26 * r1: uint8_t* ctx_memory_to
27 */
28FUNCTION_START(SwitchContext)
29    /*** save current context ***/
30    STORE_CONTEXT tmp_regid=3
31    /*** restore next context ***/
32    /* restore GPR */
33    // gpr (incl. fp): assuming that R4..R15 reside in a contiguous block
34    add r3, r1, # GPR_O(R4)
35    ldm r3, {r4-r12}
36    ldr sp, [r1, # GPR_O(SP)]
37    ldr lr, [r1, # GPR_O(LR)]
38    // arg register
39    ldr r0, [r1, # GPR_O(R0)]
40
41#ifndef PANDA_TARGET_ARM32_ABI_SOFT
42    /* restore FP */
43    // regs: assuming that D8..D15 reside in a contiguous block
44    add r3, r1, # FP_O(D8)
45    vldm r3, {d8-d15}
46    // control/status
47    ldr r3, [r1, # FP_O(FPSCR)]      // Get saved FPSCR value
48    fmxr fpscr, r3                   // and restore it
49#endif
50
51    /* branch to the restored PC */
52    ldr r3, [r1, # GPR_O(PC)]
53    bx r3
54FUNCTION_END(SwitchContext)
55
56#undef GPR_O
57#undef FP_O
58
59// we don't need executable stack.
60.section .note.GNU-stack,"",%progbits