diff options
Diffstat (limited to 'core/vm/instructions.go')
-rw-r--r-- | core/vm/instructions.go | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/core/vm/instructions.go b/core/vm/instructions.go index 766172501..6daf4e10d 100644 --- a/core/vm/instructions.go +++ b/core/vm/instructions.go @@ -302,6 +302,66 @@ func opMulmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *S return nil, nil } +// opSHL implements Shift Left +// The SHL instruction (shift left) pops 2 values from the stack, first arg1 and then arg2, +// and pushes on the stack arg2 shifted to the left by arg1 number of bits. +func opSHL(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) { + // Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards + shift, value := math.U256(stack.pop()), math.U256(stack.peek()) + defer evm.interpreter.intPool.put(shift) // First operand back into the pool + + if shift.Cmp(common.Big256) >= 0 { + value.SetUint64(0) + return nil, nil + } + n := uint(shift.Uint64()) + math.U256(value.Lsh(value, n)) + + return nil, nil +} + +// opSHR implements Logical Shift Right +// The SHR instruction (logical shift right) pops 2 values from the stack, first arg1 and then arg2, +// and pushes on the stack arg2 shifted to the right by arg1 number of bits with zero fill. +func opSHR(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) { + // Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards + shift, value := math.U256(stack.pop()), math.U256(stack.peek()) + defer evm.interpreter.intPool.put(shift) // First operand back into the pool + + if shift.Cmp(common.Big256) >= 0 { + value.SetUint64(0) + return nil, nil + } + n := uint(shift.Uint64()) + math.U256(value.Rsh(value, n)) + + return nil, nil +} + +// opSAR implements Arithmetic Shift Right +// The SAR instruction (arithmetic shift right) pops 2 values from the stack, first arg1 and then arg2, +// and pushes on the stack arg2 shifted to the right by arg1 number of bits with sign extension. +func opSAR(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) { + // Note, S256 returns (potentially) a new bigint, so we're popping, not peeking this one + shift, value := math.U256(stack.pop()), math.S256(stack.pop()) + defer evm.interpreter.intPool.put(shift) // First operand back into the pool + + if shift.Cmp(common.Big256) >= 0 { + if value.Sign() > 0 { + value.SetUint64(0) + } else { + value.SetInt64(-1) + } + stack.push(math.U256(value)) + return nil, nil + } + n := uint(shift.Uint64()) + value.Rsh(value, n) + stack.push(math.U256(value)) + + return nil, nil +} + func opSha3(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) { offset, size := stack.pop(), stack.pop() data := memory.Get(offset.Int64(), size.Int64()) |