readme

README.md

@@ -6,6 +6,13 @@ The cannon (cannon cannon cannon) is an on chain interactive fraud prover
 
 It's half geth, half of what I think truebit was supposed to be. When it's done, we'll be able to prove L1 blocks aren't fraud
 
+* It's code in Go
+* ...running an EVM
+* ...emulating a MIPS machine
+* ...running an EVM
+
+## Steps
+
 1. Get minigeth to verify a block locally paying attention to oracle (done)
 2. Compile embedded minigeth to MIPS (done)
 3. Get embedded minigeth to verify a block using the oracle (done)

contracts/MIPS.sol

@@ -39,6 +39,7 @@ contract MIPS {
       return m.WriteMemory(stateHash, addr, value);
     } else {
       assembly {
+        // TODO: this is actually doing an SLOAD first
         sstore(addr, value)
       }
     }
@@ -204,8 +205,8 @@ contract MIPS {
 
     if (opcode == 0) {
       if (func == 8 || func == 9) {
-        // jr/jalr (val is already right)
-        return stepNextPC(stateHash, uint32(nextPC), val | (func == 9 ? STORE_LINK : 0));
+        // jr/jalr
+        return stepNextPC(stateHash, uint32(nextPC), rs | (func == 9 ? STORE_LINK : 0));
       }
 
       // syscall (can read and write)

mipsevm/main.go

@@ -269,7 +269,7 @@ func main() {
 			debug = 1
 			/*steps := 1000000
 			runTest(os.Args[1], steps, interpreter, bytecode, uint64(steps)*10000)*/
-			RunMinigeth(os.Args[1], interpreter, bytecode, 100000000)
+			RunMinigeth(os.Args[1], interpreter, bytecode, 1000000000)
 		} else {
 			debug = 2
 			runTest(os.Args[1], 20, interpreter, bytecode, 1000000)