MASM Changes

Several core miden::protocol::note procedures were renamed; several kernel procedures dropped redundant outputs that duplicated their inputs; the asset vault key's metadata byte was redefined to encode AssetComposition; and the immediate form adv_push.N was removed. Custom note scripts and any MASM that consumed the removed outputs or inspected the asset-key metadata must be updated.

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Kernel/protocol proc renames: build_recipient*, extract_*_from_metadata

Summary

Several core MASM procedures in miden::protocol::note were renamed for consistency. These are used by every custom note script that computes a recipient or reads metadata.

0.14	0.15
note::build_recipient_hash	note::compute_recipient
note::build_recipient	note::compute_and_store_recipient
note::extract_sender_from_metadata	note::metadata_into_sender
note::extract_attachment_info_from_metadata	note::metadata_into_attachment_schemes

New convenience helpers were also added: note::metadata_into_note_type and note::metadata_into_tag (use the latter instead of slicing the header manually).

Migration Steps

1. Search/replace the four procedure names per the table.
2. Where you manually extracted the tag from the metadata header, switch to metadata_into_tag.

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Asset vault key & composition

Summary

The asset vault key's metadata byte was redefined to encode the new AssetComposition. The MASM word is still called ASSET_KEY (it was not renamed — AssetVaultKey is the Rust type name), and its word-level layout is unchanged:

ASSET_KEY = [asset_id_suffix, asset_id_prefix, faucet_id_suffix_and_metadata, faucet_id_prefix]

What changed is the asset-metadata packed into the low 8 bits of the third element (faucet_id_suffix_and_metadata):

Bits	Meaning
0–1	AssetComposition — COMPOSITION_NONE (0), COMPOSITION_FUNGIBLE (1), COMPOSITION_CUSTOM (2). Custom is reserved and currently rejected.
2	asset-callback flag (moved from bit 0 in v0.14).
3–7	reserved; must be zero.

The COMPOSITION_NONE / COMPOSITION_FUNGIBLE / COMPOSITION_CUSTOM constants are exported from miden::protocol::asset.

Affected Code

New and updated procedures in miden::protocol::asset (call as exec.asset::<proc>):

Procedure	Inputs → Outputs	Notes
asset::key_to_composition	[ASSET_KEY] → [asset_composition, ASSET_KEY]	New. Compare the result against the COMPOSITION_* constants.
asset::key_to_callbacks_enabled	[ASSET_KEY] → [callbacks_enabled, ASSET_KEY]	Returns 1 if callbacks are enabled, 0 otherwise (reads bit 2).
asset::key_to_faucet_id	[ASSET_KEY] → [faucet_id_suffix, faucet_id_prefix, ASSET_KEY]	Not renamed. Now masks off the metadata internally.
asset::key_into_faucet_id	[ASSET_KEY] → [faucet_id_suffix, faucet_id_prefix]	Not renamed. Consumes the key.
asset::key_to_asset_id / asset::key_into_asset_id	[ASSET_KEY] → [asset_id_suffix, asset_id_prefix(, ASSET_KEY)]	Not renamed.

The transaction kernel also adds is_fungible_asset_key ([ASSET_KEY] → [is_fungible_asset, ASSET_KEY]), equivalent to key_to_composition followed by eq.COMPOSITION_FUNGIBLE. The asset constructors (create_fungible_key, create_fungible_asset_unchecked, create_non_fungible_asset_unchecked) keep their v0.14 signatures — they encode the composition internally.

# Read the callback flag (bit moved 0 → 2; use the helper, don't mask manually)
exec.asset::key_to_callbacks_enabled
# => [callbacks_enabled, ASSET_KEY]

# Branch on the asset's composition
exec.asset::key_to_composition
# => [asset_composition, ASSET_KEY]
eq.COMPOSITION_FUNGIBLE

Migration Steps

1. If you read the callback flag by masking bit 0 of the metadata, switch to asset::key_to_callbacks_enabled — the flag now lives in bit 2.
2. To branch on the asset type, call asset::key_to_composition and compare against the COMPOSITION_* constants instead of inspecting raw bits.
3. No change is needed for asset::key_to_faucet_id, asset::key_into_faucet_id, asset::key_to_asset_id, or asset::key_into_asset_id — their names and stack effects are unchanged. Only code that hand-decodes the metadata byte is affected by the bit-layout shift; callers using these helper procs are not.

See Assets, Vault & Faucet for the matching Rust-side AssetComposition / AssetVaultKey changes.

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Redundant kernel outputs removed

Summary

Six kernel procedures stopped returning values that were identical to (or trivially recoverable from) their inputs. Custom MASM that consumed the now-removed outputs must drop the stale cleanup.

Procedure	0.14 output	0.15 output
active_note::get_assets (also input_note/output_note)	[num_assets, dest_ptr]	[num_assets]
active_note::get_storage	[NOTE_STORAGE_COMMITMENT, num_storage_items, dest_ptr]	[num_storage_items]
faucet::mint	[NEW_ASSET_VALUE]	[]
note::write_assets_to_memory	echoed inputs	trimmed

Migration Steps

1. Remove the drop / movup+drop that cleared the echoed dest_ptr after get_assets / get_storage.
2. After get_storage, the NOTE_STORAGE_COMMITMENT word is no longer on the stack — delete the dropw that consumed it.
3. After faucet::mint, do not expect NEW_ASSET_VALUE.

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adv_push.N immediate form removed; adv_pushw added

Summary

The immediate form of adv_push (adv_push.N) was removed. adv_push now always pops exactly one element from the advice stack. To push N elements, emit N consecutive adv_push instructions (or repeat.N adv_push end). A new adv_pushw instruction pushes a full word (4 elements). On the Rust AST side, Instruction::AdvPush(ImmU8) became Instruction::AdvPush plus a new Instruction::AdvPushW.

Affected Code

# Before (0.14)
adv_push.1
adv_push.4

# After (0.15)
adv_push
adv_pushw

Migration Steps

1. Replace every adv_push.N with N adv_push instructions (or repeat.N adv_push end).
2. Where you previously used adv_push.4 to fetch a word, consider adv_pushw.
3. If you build MASM AST programmatically, replace Instruction::AdvPush(n) with N Instruction::AdvPush (or Instruction::AdvPushW).

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Internal _impl precompile procedures removed

Summary

The internal _impl precompile helper procedures were removed from the core-lib public surface: ecdsa_k256_keccak::verify_prehash_impl, eddsa_ed25519::verify_prehash_impl, keccak256::hash_bytes_impl, and sha512::hash_bytes_impl. The public wrappers (verify, verify_prehash, hash_bytes, …) are unchanged and remain the supported entry points.

Migration Steps

1. If you called any *_impl precompile helper directly by fully-qualified path, switch to the corresponding public wrapper.