update the assembely as per feedback

EIPS/eip-2935.md

@@ -69,54 +69,34 @@ def resolve_blockhash(block: Block, state: State, arg: uint64):
 Exact evm assembly that can be used for the blockhash contract:
 
 ```
-// check for <=32 (<33) byte size or else revert
+// check if inputsize>32 revert
+push1 0x20
 calldatasize
-push1 0x21
 gt
-push1 0x0a
-// jump and skip revert
+push1 0x32
 jumpi
 
-push0
-push0
-revert
-
-// check if  blocknumber > input or else return 0
-jumpdest
+// check if input > blocknumber-1 then return 0
+push1 0x1
+number
+sub
 push0
 calldataload
-number
 gt
-push1 0x1a
+push1 0x2a
 jumpi
 
-// return 0
-push0
-push0
-mstore
-push1 0x20
-push0
-return
 
-// check if input + 8193 > blocknumber (input >= blocknumber - 8192) or else return 0
-jumpdest
-number
-push2 0x2001
+// check if blocknumber > input + 8192 then return 0
 push0
 calldataload
+push2 0x2000
 add
+number
 gt
-push1 0x2e
+push1 0x2a
 jumpi
 
-// return 0
-push0
-push0
-mstore
-push1 0x2e
-push0
-return
-
 // mod 8192 and sload
 jumpdest
 push2 0x2000
@@ -132,6 +112,21 @@ push1 0x20
 push0
 return
 
+// return 0
+jumpdest
+push0
+push0
+mstore
+push1 0x20
+push0
+return
+
+// revert
+jumpdest
+push0
+push0
+revert
+
 stop
 ```