1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "context_mips64.h"
18 
19 #include "base/bit_utils.h"
20 #include "quick/quick_method_frame_info.h"
21 
22 namespace art {
23 namespace mips64 {
24 
25 static constexpr uintptr_t gZero = 0;
26 
Reset()27 void Mips64Context::Reset() {
28   std::fill_n(gprs_, arraysize(gprs_), nullptr);
29   std::fill_n(fprs_, arraysize(fprs_), nullptr);
30   gprs_[SP] = &sp_;
31   gprs_[T9] = &t9_;
32   gprs_[A0] = &arg0_;
33   // Initialize registers with easy to spot debug values.
34   sp_ = Mips64Context::kBadGprBase + SP;
35   t9_ = Mips64Context::kBadGprBase + T9;
36   arg0_ = 0;
37 }
38 
FillCalleeSaves(uint8_t * frame,const QuickMethodFrameInfo & frame_info)39 void Mips64Context::FillCalleeSaves(uint8_t* frame, const QuickMethodFrameInfo& frame_info) {
40   int spill_pos = 0;
41 
42   // Core registers come first, from the highest down to the lowest.
43   for (uint32_t core_reg : HighToLowBits(frame_info.CoreSpillMask())) {
44     gprs_[core_reg] = CalleeSaveAddress(frame, spill_pos, frame_info.FrameSizeInBytes());
45     ++spill_pos;
46   }
47   DCHECK_EQ(spill_pos, POPCOUNT(frame_info.CoreSpillMask()));
48 
49   // FP registers come second, from the highest down to the lowest.
50   for (uint32_t fp_reg : HighToLowBits(frame_info.FpSpillMask())) {
51     fprs_[fp_reg] = CalleeSaveAddress(frame, spill_pos, frame_info.FrameSizeInBytes());
52     ++spill_pos;
53   }
54   DCHECK_EQ(spill_pos, POPCOUNT(frame_info.CoreSpillMask()) + POPCOUNT(frame_info.FpSpillMask()));
55 }
56 
SetGPR(uint32_t reg,uintptr_t value)57 void Mips64Context::SetGPR(uint32_t reg, uintptr_t value) {
58   CHECK_LT(reg, static_cast<uint32_t>(kNumberOfGpuRegisters));
59   DCHECK(IsAccessibleGPR(reg));
60   CHECK_NE(gprs_[reg], &gZero);  // Can't overwrite this static value since they are never reset.
61   *gprs_[reg] = value;
62 }
63 
SetFPR(uint32_t reg,uintptr_t value)64 void Mips64Context::SetFPR(uint32_t reg, uintptr_t value) {
65   CHECK_LT(reg, static_cast<uint32_t>(kNumberOfFpuRegisters));
66   DCHECK(IsAccessibleFPR(reg));
67   CHECK_NE(fprs_[reg], &gZero);  // Can't overwrite this static value since they are never reset.
68   *fprs_[reg] = value;
69 }
70 
SmashCallerSaves()71 void Mips64Context::SmashCallerSaves() {
72   // This needs to be 0 because we want a null/zero return value.
73   gprs_[V0] = const_cast<uintptr_t*>(&gZero);
74   gprs_[V1] = const_cast<uintptr_t*>(&gZero);
75   gprs_[A1] = nullptr;
76   gprs_[A0] = nullptr;
77   gprs_[A2] = nullptr;
78   gprs_[A3] = nullptr;
79   gprs_[A4] = nullptr;
80   gprs_[A5] = nullptr;
81   gprs_[A6] = nullptr;
82   gprs_[A7] = nullptr;
83 
84   // f0-f23 are caller-saved; f24-f31 are callee-saved.
85   fprs_[F0] = nullptr;
86   fprs_[F1] = nullptr;
87   fprs_[F2] = nullptr;
88   fprs_[F3] = nullptr;
89   fprs_[F4] = nullptr;
90   fprs_[F5] = nullptr;
91   fprs_[F6] = nullptr;
92   fprs_[F7] = nullptr;
93   fprs_[F8] = nullptr;
94   fprs_[F9] = nullptr;
95   fprs_[F10] = nullptr;
96   fprs_[F11] = nullptr;
97   fprs_[F12] = nullptr;
98   fprs_[F13] = nullptr;
99   fprs_[F14] = nullptr;
100   fprs_[F15] = nullptr;
101   fprs_[F16] = nullptr;
102   fprs_[F17] = nullptr;
103   fprs_[F18] = nullptr;
104   fprs_[F19] = nullptr;
105   fprs_[F20] = nullptr;
106   fprs_[F21] = nullptr;
107   fprs_[F22] = nullptr;
108   fprs_[F23] = nullptr;
109 }
110 
111 extern "C" NO_RETURN void art_quick_do_long_jump(uintptr_t*, uintptr_t*);
112 
DoLongJump()113 void Mips64Context::DoLongJump() {
114   uintptr_t gprs[kNumberOfGpuRegisters];
115   uintptr_t fprs[kNumberOfFpuRegisters];
116   for (size_t i = 0; i < kNumberOfGpuRegisters; ++i) {
117     gprs[i] = gprs_[i] != nullptr ? *gprs_[i] : Mips64Context::kBadGprBase + i;
118   }
119   for (size_t i = 0; i < kNumberOfFpuRegisters; ++i) {
120     fprs[i] = fprs_[i] != nullptr ? *fprs_[i] : Mips64Context::kBadFprBase + i;
121   }
122   art_quick_do_long_jump(gprs, fprs);
123 }
124 
125 }  // namespace mips64
126 }  // namespace art
127