71 lines
2.5 KiB
Go
71 lines
2.5 KiB
Go
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// Copyright 2024 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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// immediate denotes how many immediate bytes an operation uses. This information
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// is not required during runtime, only during EOF-validation, so is not
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// places into the op-struct in the instruction table.
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// Note: the immediates is fork-agnostic, and assumes that validity of opcodes at
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// the given time is performed elsewhere.
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var immediates [256]uint8
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// terminals denotes whether instructions can be the final opcode in a code section.
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// Note: the terminals is fork-agnostic, and assumes that validity of opcodes at
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// the given time is performed elsewhere.
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var terminals [256]bool
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func init() {
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// The legacy pushes
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for i := uint8(1); i < 33; i++ {
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immediates[int(PUSH0)+int(i)] = i
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}
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// And new eof opcodes.
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immediates[DATALOADN] = 2
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immediates[RJUMP] = 2
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immediates[RJUMPI] = 2
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immediates[RJUMPV] = 3
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immediates[CALLF] = 2
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immediates[JUMPF] = 2
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immediates[DUPN] = 1
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immediates[SWAPN] = 1
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immediates[EXCHANGE] = 1
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immediates[EOFCREATE] = 1
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immediates[RETURNCONTRACT] = 1
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// Define the terminals.
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terminals[STOP] = true
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terminals[RETF] = true
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terminals[JUMPF] = true
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terminals[RETURNCONTRACT] = true
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terminals[RETURN] = true
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terminals[REVERT] = true
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terminals[INVALID] = true
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}
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// Immediates returns the number bytes of immediates (argument not from
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// stack but from code) a given opcode has.
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// OBS:
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// - This function assumes EOF instruction-set. It cannot be upon in
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// a. pre-EOF code
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// b. post-EOF but legacy code
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// - RJUMPV is unique as it has a variable sized operand. The total size is
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// determined by the count byte which immediately follows RJUMPV. This method
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// will return '3' for RJUMPV, which is the minimum.
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func Immediates(op OpCode) int {
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return int(immediates[op])
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}
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