1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
// Copyright 2022 Risc0, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "risc0/zkvm/circuit/mem_check.h"
#include "risc0/zkvm/circuit/step_state.h"
namespace risc0::circuit {
void MemCheck::set(StepState& state) {
// Extract the memory op
BYZ_NONDET {
auto [ndCycle, addr, isWrite, low, high] = memCheck();
cycle.set(ndCycle);
memIO.address.set(addr);
memIO.isWrite.set(isWrite);
memIO.value.setLow(low);
memIO.value.setHigh(high);
}
// Do actual verification (unless cycle == 0)
// TODO: Use init/fini/etc
BYZ_IF(state.code.cycle.get()) {
Buffer prevBuf = state.getPrev(1).memCheckBuf;
BufAlloc prevAlloc(prevBuf.slice(0, 0), prevBuf);
MemCheck prev(prevAlloc);
Value addr = memIO.address.get();
Value prevAddr = prev.memIO.address.get();
BYZ_NONDET { sameAddr.set(1 - nonzero(addr - prevAddr)); }
BYZ_IF(sameAddr.get()) {
equate(addr, prevAddr);
BYZ_IF(1 - memIO.isWrite.get()) {
equate(memIO.value.low(), prev.memIO.value.low());
equate(memIO.value.high(), prev.memIO.value.high());
}
memDiff.setPartExact(cycle.get() - prev.cycle.get() - 1, 0, 20);
}
BYZ_IF(1 - sameAddr.get()) { memDiff.setPartExact(addr - prevAddr - 1, 0, 20); }
}
}
} // namespace risc0::circuit