Fix get_stake in staking precompile

Author: gztensor

runtime/src/precompiles/solidity/staking.abi

@@ -38,9 +38,9 @@
         "name": "getStake",
         "outputs": [
             {
-                "internalType": "uint64",
+                "internalType": "uint256",
                 "name": "",
-                "type": "uint64"
+                "type": "uint256"
             }
         ],
         "stateMutability": "view",

runtime/src/precompiles/solidity/staking.sol

@@ -51,7 +51,7 @@ interface IStaking {
   * @param hotkey The hotkey public key (32 bytes).
   * @param coldkey The coldkey public key (32 bytes).
   * @param netuid The subnet the stake is on (uint256).
-  * @return The current stake amount in uint64 format.
+  * @return The current stake amount in uint256 format.
   */
-  function getStake(bytes32 hotkey, bytes32 coldkey, uint256 netuid) external view returns (uint64);
+  function getStake(bytes32 hotkey, bytes32 coldkey, uint256 netuid) external view returns (uint256);
 }

runtime/src/precompiles/staking.rs

@@ -59,7 +59,7 @@ impl StakingPrecompile {
             id if id == get_method_id("removeStake(bytes32,uint256,uint256)") => {
                 Self::remove_stake(handle, &method_input)
             }
-            id if id == get_method_id("getStake(bytes32,bytes32,uint16)") => {
+            id if id == get_method_id("getStake(bytes32,bytes32,uint256)") => {
                 Self::get_stake(&method_input)
             }
             _ => Err(PrecompileFailure::Error {
@@ -112,17 +112,23 @@ impl StakingPrecompile {
 
     fn get_stake(data: &[u8]) -> PrecompileResult {
         let (hotkey, coldkey) = Self::parse_hotkey_coldkey(data)?;
-        let netuid = Self::parse_netuid(data, 0x3E)?;
+        let netuid = Self::parse_netuid(data, 0x5E)?;
 
         let stake = pallet_subtensor::Pallet::<Runtime>::get_stake_for_hotkey_and_coldkey_on_subnet(
             &hotkey.into(),
             &coldkey.into(),
             netuid,
         );
 
+        // Convert to EVM decimals
         let stake_u256 = U256::from(stake);
+        let stake_eth =
+            <Runtime as pallet_evm::Config>::BalanceConverter::into_evm_balance(stake_u256)
+                .ok_or(ExitError::InvalidRange)?;
+
+        // Format output
         let mut result = [0_u8; 32];
-        U256::to_big_endian(&stake_u256, &mut result);
+        U256::to_big_endian(&stake_eth, &mut result);
 
         Ok(PrecompileOutput {
             exit_status: ExitSucceed::Returned,