1/*
2 * Copyright (C) 2015-2019 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "JITRightShiftGenerator.h"
28
29#if ENABLE(JIT)
30
31namespace JSC {
32
33void JITRightShiftGenerator::generateFastPath(CCallHelpers& jit)
34{
35 ASSERT(m_scratchGPR != InvalidGPRReg);
36 ASSERT(m_scratchGPR != m_left.payloadGPR());
37 ASSERT(m_scratchGPR != m_right.payloadGPR());
38#if USE(JSVALUE32_64)
39 ASSERT(m_scratchGPR != m_left.tagGPR());
40 ASSERT(m_scratchGPR != m_right.tagGPR());
41 ASSERT(m_scratchFPR != InvalidFPRReg);
42#endif
43
44 ASSERT(!m_leftOperand.isConstInt32() || !m_rightOperand.isConstInt32());
45
46 m_didEmitFastPath = true;
47
48 if (m_rightOperand.isConstInt32()) {
49 // Try to do (intVar >> intConstant).
50 CCallHelpers::Jump notInt = jit.branchIfNotInt32(m_left);
51
52 jit.moveValueRegs(m_left, m_result);
53 int32_t shiftAmount = m_rightOperand.asConstInt32() & 0x1f;
54 if (shiftAmount) {
55 if (m_shiftType == SignedShift)
56 jit.rshift32(CCallHelpers::Imm32(shiftAmount), m_result.payloadGPR());
57 else
58 jit.urshift32(CCallHelpers::Imm32(shiftAmount), m_result.payloadGPR());
59#if USE(JSVALUE64)
60 jit.or64(GPRInfo::numberTagRegister, m_result.payloadGPR());
61#endif
62 }
63
64 if (jit.supportsFloatingPointTruncate()) {
65 m_endJumpList.append(jit.jump()); // Terminate the above case before emitting more code.
66
67 // Try to do (doubleVar >> intConstant).
68 notInt.link(&jit);
69
70 m_slowPathJumpList.append(jit.branchIfNotNumber(m_left, m_scratchGPR));
71
72 jit.unboxDoubleNonDestructive(m_left, m_leftFPR, m_scratchGPR, m_scratchFPR);
73#if CPU(ARM64)
74 if (MacroAssemblerARM64::supportsDoubleToInt32ConversionUsingJavaScriptSemantics())
75 jit.convertDoubleToInt32UsingJavaScriptSemantics(m_leftFPR, m_scratchGPR);
76 else
77#endif
78 {
79 m_slowPathJumpList.append(jit.branchTruncateDoubleToInt32(m_leftFPR, m_scratchGPR));
80 }
81
82 if (shiftAmount) {
83 if (m_shiftType == SignedShift)
84 jit.rshift32(CCallHelpers::Imm32(shiftAmount), m_scratchGPR);
85 else
86 jit.urshift32(CCallHelpers::Imm32(shiftAmount), m_scratchGPR);
87 }
88 jit.boxInt32(m_scratchGPR, m_result);
89
90 } else
91 m_slowPathJumpList.append(notInt);
92
93 } else {
94 // Try to do (intConstant >> intVar) or (intVar >> intVar).
95 m_slowPathJumpList.append(jit.branchIfNotInt32(m_right));
96
97 GPRReg rightOperandGPR = m_right.payloadGPR();
98 if (rightOperandGPR == m_result.payloadGPR())
99 rightOperandGPR = m_scratchGPR;
100
101 CCallHelpers::Jump leftNotInt;
102 if (m_leftOperand.isConstInt32()) {
103 jit.move(m_right.payloadGPR(), rightOperandGPR);
104#if USE(JSVALUE32_64)
105 jit.move(m_right.tagGPR(), m_result.tagGPR());
106#endif
107 jit.move(CCallHelpers::Imm32(m_leftOperand.asConstInt32()), m_result.payloadGPR());
108 } else {
109 leftNotInt = jit.branchIfNotInt32(m_left);
110 jit.move(m_right.payloadGPR(), rightOperandGPR);
111 jit.moveValueRegs(m_left, m_result);
112 }
113
114 if (m_shiftType == SignedShift)
115 jit.rshift32(rightOperandGPR, m_result.payloadGPR());
116 else
117 jit.urshift32(rightOperandGPR, m_result.payloadGPR());
118#if USE(JSVALUE64)
119 jit.or64(GPRInfo::numberTagRegister, m_result.payloadGPR());
120#endif
121 if (m_leftOperand.isConstInt32())
122 return;
123
124 if (jit.supportsFloatingPointTruncate()) {
125 m_endJumpList.append(jit.jump()); // Terminate the above case before emitting more code.
126
127 // Try to do (doubleVar >> intVar).
128 leftNotInt.link(&jit);
129
130 m_slowPathJumpList.append(jit.branchIfNotNumber(m_left, m_scratchGPR));
131 jit.unboxDoubleNonDestructive(m_left, m_leftFPR, m_scratchGPR, m_scratchFPR);
132#if CPU(ARM64)
133 if (MacroAssemblerARM64::supportsDoubleToInt32ConversionUsingJavaScriptSemantics())
134 jit.convertDoubleToInt32UsingJavaScriptSemantics(m_leftFPR, m_scratchGPR);
135 else
136#endif
137 {
138 m_slowPathJumpList.append(jit.branchTruncateDoubleToInt32(m_leftFPR, m_scratchGPR));
139 }
140
141 if (m_shiftType == SignedShift)
142 jit.rshift32(m_right.payloadGPR(), m_scratchGPR);
143 else
144 jit.urshift32(m_right.payloadGPR(), m_scratchGPR);
145 jit.boxInt32(m_scratchGPR, m_result);
146
147 } else
148 m_slowPathJumpList.append(leftNotInt);
149 }
150}
151
152} // namespace JSC
153
154#endif // ENABLE(JIT)
155