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1 // Copyright 2012 the V8 project authors. All rights reserved.7 | 1 // Copyright 2012 the V8 project authors. All rights reserved.7 |
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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1324 } | 1324 } |
1325 | 1325 |
1326 // If the divisor is negative, we have to negate and handle edge cases. | 1326 // If the divisor is negative, we have to negate and handle edge cases. |
1327 if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) { | 1327 if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) { |
1328 __ Move(scratch, dividend); | 1328 __ Move(scratch, dividend); |
1329 } | 1329 } |
1330 __ Subu(result, zero_reg, dividend); | 1330 __ Subu(result, zero_reg, dividend); |
1331 if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) { | 1331 if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) { |
1332 DeoptimizeIf(eq, instr->environment(), result, Operand(zero_reg)); | 1332 DeoptimizeIf(eq, instr->environment(), result, Operand(zero_reg)); |
1333 } | 1333 } |
1334 if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) { | 1334 |
1335 // Note that we could emit branch-free code, but that would need one more | 1335 // If the negation could not overflow, simply shifting is OK. |
1336 // register. | 1336 if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) { |
1337 __ Xor(at, scratch, result); | |
1338 if (divisor == -1) { | |
1339 DeoptimizeIf(ge, instr->environment(), at, Operand(zero_reg)); | |
1340 __ sra(result, dividend, shift); | |
1341 } else { | |
1342 Label no_overflow, done; | |
1343 __ Branch(&no_overflow, lt, at, Operand(zero_reg)); | |
1344 __ li(result, Operand(kMinInt / divisor)); | |
1345 __ Branch(&done); | |
1346 __ bind(&no_overflow); | |
1347 __ sra(result, dividend, shift); | |
1348 __ bind(&done); | |
1349 } | |
1350 } else { | |
1351 __ sra(result, dividend, shift); | 1337 __ sra(result, dividend, shift); |
| 1338 return; |
1352 } | 1339 } |
| 1340 |
| 1341 // Dividing by -1 is basically negation, unless we overflow. |
| 1342 __ Xor(at, scratch, result); |
| 1343 if (divisor == -1) { |
| 1344 DeoptimizeIf(ge, instr->environment(), at, Operand(zero_reg)); |
| 1345 return; |
| 1346 } |
| 1347 |
| 1348 Label no_overflow, done; |
| 1349 __ Branch(&no_overflow, lt, at, Operand(zero_reg)); |
| 1350 __ li(result, Operand(kMinInt / divisor)); |
| 1351 __ Branch(&done); |
| 1352 __ bind(&no_overflow); |
| 1353 __ sra(result, dividend, shift); |
| 1354 __ bind(&done); |
1353 } | 1355 } |
1354 | 1356 |
1355 | 1357 |
1356 void LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) { | 1358 void LCodeGen::DoFlooringDivByConstI(LFlooringDivByConstI* instr) { |
1357 Register dividend = ToRegister(instr->dividend()); | 1359 Register dividend = ToRegister(instr->dividend()); |
1358 int32_t divisor = instr->divisor(); | 1360 int32_t divisor = instr->divisor(); |
1359 Register result = ToRegister(instr->result()); | 1361 Register result = ToRegister(instr->result()); |
1360 ASSERT(!dividend.is(result)); | 1362 ASSERT(!dividend.is(result)); |
1361 | 1363 |
1362 if (divisor == 0) { | 1364 if (divisor == 0) { |
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5815 __ Subu(scratch, result, scratch); | 5817 __ Subu(scratch, result, scratch); |
5816 __ lw(result, FieldMemOperand(scratch, | 5818 __ lw(result, FieldMemOperand(scratch, |
5817 FixedArray::kHeaderSize - kPointerSize)); | 5819 FixedArray::kHeaderSize - kPointerSize)); |
5818 __ bind(&done); | 5820 __ bind(&done); |
5819 } | 5821 } |
5820 | 5822 |
5821 | 5823 |
5822 #undef __ | 5824 #undef __ |
5823 | 5825 |
5824 } } // namespace v8::internal | 5826 } } // namespace v8::internal |
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