core/vm: use uint256 in EVM implementation (#20787)

* core/vm: use fixed uint256 library instead of big

* core/vm: remove intpools

* core/vm: upgrade uint256, fixes uint256.NewFromBig

* core/vm: use uint256.Int by value in Stack

* core/vm: upgrade uint256 to v1.0.0

* core/vm: don't preallocate space for 1024 stack items (only 16)

Co-authored-by: Martin Holst Swende <martin@swende.se>

core/vm/memory.go

@@ -18,9 +18,8 @@ package vm
 
 import (
 	"fmt"
-	"math/big"
 
-	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/holiman/uint256"
 )
 
 // Memory implements a simple memory model for the ethereum virtual machine.
@@ -50,7 +49,7 @@ func (m *Memory) Set(offset, size uint64, value []byte) {
 
 // Set32 sets the 32 bytes starting at offset to the value of val, left-padded with zeroes to
 // 32 bytes.
-func (m *Memory) Set32(offset uint64, val *big.Int) {
+func (m *Memory) Set32(offset uint64, val *uint256.Int) {
 	// length of store may never be less than offset + size.
 	// The store should be resized PRIOR to setting the memory
 	if offset+32 > uint64(len(m.store)) {
@@ -59,7 +58,7 @@ func (m *Memory) Set32(offset uint64, val *big.Int) {
 	// Zero the memory area
 	copy(m.store[offset:offset+32], []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
 	// Fill in relevant bits
-	math.ReadBits(val, m.store[offset:offset+32])
+	val.WriteToSlice(m.store[offset:])
 }
 
 // Resize resizes the memory to size