From 3285a0fda37207ca1b79ac28e2c12c6f5efff89b Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Sun, 28 May 2017 23:39:33 +0200
Subject: core/vm, common/math: Add fast getByte for bigints, improve opByte
---
core/vm/instructions.go | 13 ++++++-------
core/vm/instructions_test.go | 43 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 49 insertions(+), 7 deletions(-)
create mode 100644 core/vm/instructions_test.go
(limited to 'core/vm')
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 42f1781d8..bcaf18e8a 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -256,15 +256,14 @@ func opXor(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stac
}
func opByte(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
- th, val := stack.pop(), stack.pop()
- if th.Cmp(big.NewInt(32)) < 0 {
- byte := evm.interpreter.intPool.get().SetInt64(int64(math.PaddedBigBytes(val, 32)[th.Int64()]))
- stack.push(byte)
+ th, val := stack.pop(), stack.peek()
+ if th.Cmp(common.Big32) < 0 {
+ b := math.BigEndian32ByteAt(val, int(th.Int64()))
+ val.SetInt64(int64(b))
} else {
- stack.push(new(big.Int))
+ val.SetUint64(0)
}
-
- evm.interpreter.intPool.put(th, val)
+ evm.interpreter.intPool.put(th)
return nil, nil
}
func opAddmod(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
diff --git a/core/vm/instructions_test.go b/core/vm/instructions_test.go
new file mode 100644
index 000000000..50264bc3e
--- /dev/null
+++ b/core/vm/instructions_test.go
@@ -0,0 +1,43 @@
+package vm
+
+import (
+ "math/big"
+ "testing"
+
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/params"
+)
+
+func TestByteOp(t *testing.T) {
+
+ var (
+ env = NewEVM(Context{}, nil, params.TestChainConfig, Config{EnableJit: false, ForceJit: false})
+ stack = newstack()
+ )
+ tests := []struct {
+ v string
+ th uint64
+ expected *big.Int
+ }{
+ {"ABCDEF0908070605040302010000000000000000000000000000000000000000", 0, big.NewInt(0xAB)},
+ {"ABCDEF0908070605040302010000000000000000000000000000000000000000", 1, big.NewInt(0xCD)},
+ {"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 0, big.NewInt(0x00)},
+ {"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 1, big.NewInt(0xCD)},
+ {"0000000000000000000000000000000000000000000000000000000000102030", 31, big.NewInt(0x30)},
+ {"0000000000000000000000000000000000000000000000000000000000102030", 30, big.NewInt(0x20)},
+ {"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 32, big.NewInt(0x0)},
+ {"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 0xFFFFFFFFFFFFFFFF, big.NewInt(0x0)},
+ }
+ pc := uint64(0)
+ for _, test := range tests {
+ val := new(big.Int).SetBytes(common.Hex2Bytes(test.v))
+ th := new(big.Int).SetUint64(test.th)
+ stack.push(val)
+ stack.push(th)
+ opByte(&pc, env, nil, nil, stack)
+ actual := stack.pop()
+ if actual.Cmp(test.expected) != 0 {
+ t.Fatalf("Expected [%v] %v:th byte to be %v, was %v.", test.v, test.th, test.expected, actual)
+ }
+ }
+}
--
cgit v1.2.3