# MOVEVM
[← Target Reference](../../reference/targets.md)
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## VM Parameters
| Architecture | Register/hybrid (Move bytecode) |
| Word size | 64-bit (u64, u128, u256 native) |
| Hash function | SHA3-256 |
| Digest width | 32 bytes |
| Stack depth | Register-addressed (locals + operand stack) |
| Output format | `.mv` (Move bytecode modules) |
| Cost model | Gas (per-bytecode-instruction + storage) |
Resource-oriented bytecode VM. Move's type system enforces linear resource
semantics — assets cannot be copied or implicitly dropped, only moved. The
compiler produces `.mv` modules via dedicated `MoveLowering`.
Move bytecode uses a hybrid architecture: local variables are register-addressed,
but execution uses an operand stack for intermediate values. The bytecode
verifier enforces type safety, resource linearity, and reference safety
before execution.
Native precompiles: SHA3-256, ed25519 verification, BLS12-381 operations.
See [os/sui.md](../../os/sui/README.md) and [os/aptos.md](../../os/aptos/README.md) for
OS-specific runtime bindings. Same `.mv` bytecode output, different
`ext.*` bindings.
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## Cost Model (Gas)
Per-bytecode-instruction gas plus storage operations.
| Arithmetic / logic | 1 | Most bytecode instructions |
| Move / copy | 1 | Resource move, copy (if allowed) |
| Borrow | 1 | Reference creation |
| Call | 10 | Function invocation |
| Storage read | 300-1,000 | Global borrow (OS-dependent) |
| Storage write | 300-1,000 | Global move_to (OS-dependent) |
Storage costs vary by OS (Sui vs Aptos). Detailed cost model planned.