fix: have mips step check register offset instead of overwrite (#238)

Existing step logic wrote the register offset into memory but the
compiler should already be doing this when the struct is defined.
Instead of writing directly into memory, this change verifies that
the memory at that location has the expected value which will
catch any cases where the compiler's memory allocation mechanism
changes in the future.

packages/contracts-bedrock/semver-lock.json

@@ -140,8 +140,8 @@
     "sourceCodeHash": "0x3ff4a3f21202478935412d47fd5ef7f94a170402ddc50e5c062013ce5544c83f"
   },
   "src/cannon/MIPS.sol": {
-    "initCodeHash": "0xb001e9a981943f3711836b8b7ce8f40122e9e124249eee64737cf2b4e5d009d6",
-    "sourceCodeHash": "0x185a37ed58c94527410cd35e35cae0f9372e364a4f28140c3e443349676a0a28"
+    "initCodeHash": "0x8c59913b880e1529a543657e24ac30b17c2ce901b4309211b5c2bc703219271d",
+    "sourceCodeHash": "0xfa6e6eacba6be2c9489f828f8a50dda40565eef5c73a2cf8e274e1fd4410d38a"
   },
   "src/cannon/MIPS2.sol": {
     "initCodeHash": "0xf3ff16b352e256534761844d49e159c267dd09e79bc9ddec78d0c90f8746ea20",

packages/contracts-bedrock/src/cannon/MIPS.sol

@@ -262,8 +262,13 @@ contract MIPS is ISemver {
                     revert(ptr, 0x04)
                 }
 
+                // Compiler should have done this already
+                if iszero(eq(mload(m), add(m, 32))) {
+                    // expected registers offset check
+                    revert(0, 0)
+                }
+
                 // Unpack register calldata into memory
-                mstore(m, add(m, 32)) // offset to registers
                 m := add(m, 32)
                 for { let i := 0 } lt(i, 32) { i := add(i, 1) } { c, m := putField(c, m, 4) }
             }

packages/contracts-bedrock/test/kontrol/proofs/utils/DeploymentSummary.sol

@@ -27,7 +27,7 @@ contract DeploymentSummary is DeploymentSummaryCode {
     address internal constant l1StandardBridgeProxyAddress = 0x20A42a5a785622c6Ba2576B2D6e924aA82BFA11D;
     address internal constant l2OutputOracleAddress = 0x19652082F846171168Daf378C4fD3ee85a0D4A60;
     address internal constant l2OutputOracleProxyAddress = 0x39Af23E00F1e662025aA01b0cEdA19542B78DF99;
-    address internal constant mipsAddress = 0xc8b67F21b0773A778e1Ca113CbFa9327fef75750;
+    address internal constant mipsAddress = 0x4e6F9442A0B4810fD9Ce770740e1d33e9B848555;
     address internal constant optimismMintableERC20FactoryAddress = 0x39Aea2Dd53f2d01c15877aCc2791af6BDD7aD567;
     address internal constant optimismMintableERC20FactoryProxyAddress = 0xc7B87b2b892EA5C3CfF47168881FE168C00377FB;
     address internal constant optimismPortalAddress = 0xbdD90485FCbcac869D5b5752179815a3103d8131;

packages/contracts-bedrock/test/kontrol/proofs/utils/DeploymentSummaryFaultProofs.sol

@@ -27,7 +27,7 @@ contract DeploymentSummaryFaultProofs is DeploymentSummaryFaultProofsCode {
     address internal constant l1StandardBridgeProxyAddress = 0x20A42a5a785622c6Ba2576B2D6e924aA82BFA11D;
     address internal constant l2OutputOracleAddress = 0x19652082F846171168Daf378C4fD3ee85a0D4A60;
     address internal constant l2OutputOracleProxyAddress = 0x39Af23E00F1e662025aA01b0cEdA19542B78DF99;
-    address internal constant mipsAddress = 0xc8b67F21b0773A778e1Ca113CbFa9327fef75750;
+    address internal constant mipsAddress = 0x4e6F9442A0B4810fD9Ce770740e1d33e9B848555;
     address internal constant optimismMintableERC20FactoryAddress = 0x39Aea2Dd53f2d01c15877aCc2791af6BDD7aD567;
     address internal constant optimismMintableERC20FactoryProxyAddress = 0xc7B87b2b892EA5C3CfF47168881FE168C00377FB;
     address internal constant optimismPortalAddress = 0xbdD90485FCbcac869D5b5752179815a3103d8131;