# `EEVM.Interpreter.Instructions.System.Calls`
[🔗](https://github.com/mw2000/eevm/blob/main/lib/eevm/interpreter/instructions/system/calls.ex#L1)

Cross-contract call opcodes.

This module handles the most complex EVM operations — those that spawn nested
execution frames and interact with the world state.

## Cross-Contract Calls

- **CALL** (0xF1) — calls another contract with optional value transfer.
- **CALLCODE** (0xF2) — like CALL but executes the target's code in the
  caller's storage context (legacy, superseded by DELEGATECALL).
- **DELEGATECALL** (0xF4) — executes the target's code in the caller's
  context, preserving `msg.sender` and `msg.value` (EIP-7).
- **STATICCALL** (0xFA) — read-only call that reverts on state changes (EIP-214).

All call opcodes use EIP-150 gas forwarding: `min(requested, available - available/64)`.

## Target access and EIP-7702 delegation

Each call charges EIP-2929 cold access for its target on top of the warm
cost in the static table. From Prague, a target whose code is a delegation
designator (`0xef0100 || delegate`) runs the delegate's code, charges the
delegate's cold or warm access as well, and never dispatches to a
precompile, even when the delegate is one.

# `execute`

```elixir
@spec execute(non_neg_integer(), EEVM.Interpreter.MachineState.t()) ::
  {:ok, EEVM.Interpreter.MachineState.t()}
  | {:error, atom(), EEVM.Interpreter.MachineState.t()}
```

Execute CALL (0xF1), CALLCODE (0xF2), DELEGATECALL (0xF4), or STATICCALL (0xFA).

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*Consult [api-reference.md](api-reference.md) for complete listing*