Update EIP-4200: New opcodes for RJUMP*

Merged by EIP-Bot.

EIPS/eip-4200.md

@@ -37,9 +37,9 @@ The main benefit of these instruction is reduced gas cost (both at deploy and ex
 
 We introduce three new instructions on the same block number [EIP-3540](./eip-3540.md) is activated on:
 
-1. `RJUMP` (0x5c) - relative jump
-2. `RJUMPI` (0x5d) - conditional relative jump
-3. `RJUMPV` (0x5e) - relative jump via jump table
+1. `RJUMP` (0xe0) - relative jump
+2. `RJUMPI` (0xe1) - conditional relative jump
+3. `RJUMPV` (0xe2) - relative jump via jump table
 
 If the code is legacy bytecode, all of these instructions result in an *exceptional halt*. (*Note: This means no change to behaviour.*)
 
@@ -154,100 +154,6 @@ This change poses no risk to backwards compatibility, as it is introduced at the
     - `case` outside of table bounds (`case > max_index`, fallback case)
     - `case` > 255
 
-## Reference Implementation
-
-```python
-# The ranges below are as specified in the Yellow Paper.
-# Note: range(s, e) excludes e, hence the +1
-valid_opcodes = [
-    *range(0x00, 0x0b + 1),
-    *range(0x10, 0x1d + 1),
-    0x20,
-    *range(0x30, 0x3f + 1),
-    *range(0x40, 0x48 + 1),
-    *range(0x50, 0x5e + 1),
-    *range(0x60, 0x6f + 1),
-    *range(0x70, 0x7f + 1),
-    *range(0x80, 0x8f + 1),
-    *range(0x90, 0x9f + 1),
-    *range(0xa0, 0xa4 + 1),
-    # Note: 0xfe is considered assigned.
-    *range(0xf0, 0xf5 + 1), 0xfa, 0xfd, 0xfe, 0xff
-]
-
-# STOP, RETURN, REVERT, INVALID, SELFDESTRUCT
-terminating_opcodes = [ 0x00, 0xf3, 0xfd, 0xfe, 0xff ]
-
-immediate_sizes = 256 * [0]
-immediate_sizes[0x5c] = 2  # RJUMP
-immediate_sizes[0x5d] = 2  # RJUMPI
-for opcode in range(0x60, 0x7f + 1):  # PUSH1..PUSH32
-    immediate_sizes[opcode] = opcode - 0x60 + 1
-
-# Raises ValidationException on invalid code
-def validate_code(code: bytes):
-    # Note that EOF1 already asserts this with the code section requirements
-    assert len(code) > 0
-
-    opcode = 0
-    pos = 0
-    rjumpdests = set()
-    immediates = set()
-    while pos < len(code):
-        # Ensure the opcode is valid
-        opcode = code[pos]
-        pos += 1
-        if not opcode in valid_opcodes:
-            raise ValidationException("undefined instruction")
-
-        pc_post_instruction = pos + immediate_sizes[opcode]
-
-        if opcode == 0x5c or opcode == 0x5d:
-            if pos + 2 > len(code):
-                raise ValidationException("truncated relative jump offset")
-            offset = int.from_bytes(code[pos:pos+2], byteorder = "big", signed = True)
-
-            rjumpdest = pc_post_instruction + offset
-            if rjumpdest < 0 or rjumpdest >= len(code):
-                raise ValidationException("relative jump destination out of bounds")
-
-            rjumpdests.add(rjumpdest)
-        elif opcode == 0x5e:
-            if pos + 1 > len(code):
-                raise ValidationException("truncated jump table")
-            jump_table_size = code[pos] + 1
-
-            pc_post_instruction = pos + 1 + 2 * jump_table_size
-            if pc_post_instruction > len(code):
-                raise ValidationException("truncated jump table")
-
-            for offset_pos in range(pos + 1, pc_post_instruction, 2):
-                offset = int.from_bytes(code[offset_pos:offset_pos+2], byteorder = "big", signed = True)
-
-                rjumpdest = pc_post_instruction + offset
-                if rjumpdest < 0 or rjumpdest >= len(code):
-                    raise ValidationException("relative jump destination out of bounds")
-                rjumpdests.add(rjumpdest)
-
-
-        # Save immediate value positions
-        immediates.update(range(pos, pc_post_instruction))
-        # Skip immediates
-        pos = pc_post_instruction
-
-    # Ensure last opcode's immediate doesn't go over code end
-    if pos != len(code):        
-        raise ValidationException("truncated immediate")
-
-    # opcode is the *last opcode*
-    if not opcode in terminating_opcodes:
-        raise ValidationException("no terminating instruction")
-
-    # Ensure relative jump destinations don't target immediates
-    if not rjumpdests.isdisjoint(immediates):
-        raise ValidationException("relative jump destination targets immediate")
-```
-
 ## Security Considerations
 
 TBA