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1 // Copyright 2012 the V8 project authors. All rights reserved. | 1 // Copyright 2012 the V8 project authors. All rights reserved. |
2 // Redistribution and use in source and binary forms, with or without | 2 // Redistribution and use in source and binary forms, with or without |
3 // modification, are permitted provided that the following conditions are | 3 // modification, are permitted provided that the following conditions are |
4 // met: | 4 // met: |
5 // | 5 // |
6 // * Redistributions of source code must retain the above copyright | 6 // * Redistributions of source code must retain the above copyright |
7 // notice, this list of conditions and the following disclaimer. | 7 // notice, this list of conditions and the following disclaimer. |
8 // * Redistributions in binary form must reproduce the above | 8 // * Redistributions in binary form must reproduce the above |
9 // copyright notice, this list of conditions and the following | 9 // copyright notice, this list of conditions and the following |
10 // disclaimer in the documentation and/or other materials provided | 10 // disclaimer in the documentation and/or other materials provided |
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1027 DeoptimizeIf(mi, instr->environment()); | 1027 DeoptimizeIf(mi, instr->environment()); |
1028 __ bind(&ok); | 1028 __ bind(&ok); |
1029 // Load the result and we are done. | 1029 // Load the result and we are done. |
1030 __ mov(result, scratch2); | 1030 __ mov(result, scratch2); |
1031 } | 1031 } |
1032 | 1032 |
1033 __ bind(&done); | 1033 __ bind(&done); |
1034 } | 1034 } |
1035 | 1035 |
1036 | 1036 |
1037 void LCodeGen::EmitSignedIntegerDivisionByConstant( | |
1038 Register result, | |
1039 Register dividend, | |
1040 int32_t divisor, | |
1041 Register remainder, | |
1042 Register scratch, | |
1043 LEnvironment* environment) { | |
1044 ASSERT(!AreAliased(dividend, scratch, ip)); | |
1045 ASSERT(LChunkBuilder::HasMagicNumberForDivisor(divisor)); | |
1046 | |
1047 uint32_t divisor_abs = abs(divisor); | |
1048 | |
1049 int32_t power_of_2_factor = | |
1050 CompilerIntrinsics::CountTrailingZeros(divisor_abs); | |
1051 | |
1052 switch (divisor_abs) { | |
1053 case 0: | |
1054 DeoptimizeIf(al, environment); | |
1055 return; | |
1056 | |
1057 case 1: | |
1058 if (divisor > 0) { | |
1059 __ Move(result, dividend); | |
1060 } else { | |
1061 __ rsb(result, dividend, Operand(0), SetCC); | |
1062 DeoptimizeIf(vs, environment); | |
1063 } | |
1064 // Compute the remainder. | |
1065 __ mov(remainder, Operand(0)); | |
1066 return; | |
1067 | |
1068 default: | |
1069 if (IsPowerOf2(divisor_abs)) { | |
1070 // Branch and condition free code for integer division by a power | |
1071 // of two. | |
1072 int32_t power = WhichPowerOf2(divisor_abs); | |
1073 if (power > 1) { | |
1074 __ mov(scratch, Operand(dividend, ASR, power - 1)); | |
1075 } | |
1076 __ add(scratch, dividend, Operand(scratch, LSR, 32 - power)); | |
1077 __ mov(result, Operand(scratch, ASR, power)); | |
1078 // Negate if necessary. | |
1079 // We don't need to check for overflow because the case '-1' is | |
1080 // handled separately. | |
1081 if (divisor < 0) { | |
1082 ASSERT(divisor != -1); | |
1083 __ rsb(result, result, Operand(0)); | |
1084 } | |
1085 // Compute the remainder. | |
1086 if (divisor > 0) { | |
1087 __ sub(remainder, dividend, Operand(result, LSL, power)); | |
1088 } else { | |
1089 __ add(remainder, dividend, Operand(result, LSL, power)); | |
1090 } | |
1091 return; | |
1092 } else { | |
1093 // Use magic numbers for a few specific divisors. | |
1094 // Details and proofs can be found in: | |
1095 // - Hacker's Delight, Henry S. Warren, Jr. | |
1096 // - The PowerPC Compiler Writer’s Guide | |
1097 // and probably many others. | |
1098 // | |
1099 // We handle | |
1100 // <divisor with magic numbers> * <power of 2> | |
1101 // but not | |
1102 // <divisor with magic numbers> * <other divisor with magic numbers> | |
1103 DivMagicNumbers magic_numbers = | |
1104 DivMagicNumberFor(divisor_abs >> power_of_2_factor); | |
1105 // Branch and condition free code for integer division by a power | |
1106 // of two. | |
1107 const int32_t M = magic_numbers.M; | |
1108 const int32_t s = magic_numbers.s + power_of_2_factor; | |
1109 | |
1110 __ mov(ip, Operand(M)); | |
1111 __ smull(ip, scratch, dividend, ip); | |
1112 if (M < 0) { | |
1113 __ add(scratch, scratch, Operand(dividend)); | |
1114 } | |
1115 if (s > 0) { | |
1116 __ mov(scratch, Operand(scratch, ASR, s)); | |
1117 } | |
1118 __ add(result, scratch, Operand(dividend, LSR, 31)); | |
1119 if (divisor < 0) __ rsb(result, result, Operand(0)); | |
1120 // Compute the remainder. | |
1121 __ mov(ip, Operand(divisor)); | |
1122 // This sequence could be replaced with 'mls' when | |
1123 // it gets implemented. | |
1124 __ mul(scratch, result, ip); | |
1125 __ sub(remainder, dividend, scratch); | |
1126 } | |
1127 } | |
1128 } | |
1129 | |
1130 | |
1131 void LCodeGen::DoDivI(LDivI* instr) { | 1037 void LCodeGen::DoDivI(LDivI* instr) { |
1132 class DeferredDivI: public LDeferredCode { | 1038 class DeferredDivI: public LDeferredCode { |
1133 public: | 1039 public: |
1134 DeferredDivI(LCodeGen* codegen, LDivI* instr) | 1040 DeferredDivI(LCodeGen* codegen, LDivI* instr) |
1135 : LDeferredCode(codegen), instr_(instr) { } | 1041 : LDeferredCode(codegen), instr_(instr) { } |
1136 virtual void Generate() { | 1042 virtual void Generate() { |
1137 codegen()->DoDeferredBinaryOpStub(instr_, Token::DIV); | 1043 codegen()->DoDeferredBinaryOpStub(instr_, Token::DIV); |
1138 } | 1044 } |
1139 virtual LInstruction* instr() { return instr_; } | 1045 virtual LInstruction* instr() { return instr_; } |
1140 private: | 1046 private: |
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1202 __ JumpIfNotSmi(result, &deoptimize); | 1108 __ JumpIfNotSmi(result, &deoptimize); |
1203 __ SmiUntag(result); | 1109 __ SmiUntag(result); |
1204 __ b(&done); | 1110 __ b(&done); |
1205 | 1111 |
1206 __ bind(&deoptimize); | 1112 __ bind(&deoptimize); |
1207 DeoptimizeIf(al, instr->environment()); | 1113 DeoptimizeIf(al, instr->environment()); |
1208 __ bind(&done); | 1114 __ bind(&done); |
1209 } | 1115 } |
1210 | 1116 |
1211 | 1117 |
1212 void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv* instr) { | |
1213 const Register result = ToRegister(instr->result()); | |
1214 const Register left = ToRegister(instr->InputAt(0)); | |
1215 const Register remainder = ToRegister(instr->TempAt(0)); | |
1216 const Register scratch = scratch0(); | |
1217 | |
1218 // We only optimize this for division by constants, because the standard | |
1219 // integer division routine is usually slower than transitionning to VFP. | |
1220 // This could be optimized on processors with SDIV available. | |
1221 ASSERT(instr->InputAt(1)->IsConstantOperand()); | |
1222 int32_t divisor = ToInteger32(LConstantOperand::cast(instr->InputAt(1))); | |
1223 if (divisor < 0) { | |
1224 __ cmp(left, Operand(0)); | |
1225 DeoptimizeIf(eq, instr->environment()); | |
1226 } | |
1227 EmitSignedIntegerDivisionByConstant(result, | |
1228 left, | |
1229 divisor, | |
1230 remainder, | |
1231 scratch, | |
1232 instr->environment()); | |
1233 // We operated a truncating division. Correct the result if necessary. | |
1234 __ cmp(remainder, Operand(0)); | |
1235 __ teq(remainder, Operand(divisor), ne); | |
1236 __ sub(result, result, Operand(1), LeaveCC, mi); | |
1237 } | |
1238 | |
1239 | |
1240 template<int T> | 1118 template<int T> |
1241 void LCodeGen::DoDeferredBinaryOpStub(LTemplateInstruction<1, 2, T>* instr, | 1119 void LCodeGen::DoDeferredBinaryOpStub(LTemplateInstruction<1, 2, T>* instr, |
1242 Token::Value op) { | 1120 Token::Value op) { |
1243 Register left = ToRegister(instr->InputAt(0)); | 1121 Register left = ToRegister(instr->InputAt(0)); |
1244 Register right = ToRegister(instr->InputAt(1)); | 1122 Register right = ToRegister(instr->InputAt(1)); |
1245 | 1123 |
1246 PushSafepointRegistersScope scope(this, Safepoint::kWithRegistersAndDoubles); | 1124 PushSafepointRegistersScope scope(this, Safepoint::kWithRegistersAndDoubles); |
1247 // Move left to r1 and right to r0 for the stub call. | 1125 // Move left to r1 and right to r0 for the stub call. |
1248 if (left.is(r1)) { | 1126 if (left.is(r1)) { |
1249 __ Move(r0, right); | 1127 __ Move(r0, right); |
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5296 __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize)); | 5174 __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize)); |
5297 __ ldr(result, FieldMemOperand(scratch, | 5175 __ ldr(result, FieldMemOperand(scratch, |
5298 FixedArray::kHeaderSize - kPointerSize)); | 5176 FixedArray::kHeaderSize - kPointerSize)); |
5299 __ bind(&done); | 5177 __ bind(&done); |
5300 } | 5178 } |
5301 | 5179 |
5302 | 5180 |
5303 #undef __ | 5181 #undef __ |
5304 | 5182 |
5305 } } // namespace v8::internal | 5183 } } // namespace v8::internal |
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