refactor: simplify move_asset_to_note

miden-lib/asm/kernels/transaction/api.masm

@@ -504,8 +504,8 @@ end
 
 #! Creates a new note and returns the index of the note.
 #!
-#! Inputs: [tag, aux, note_type, RECIPIENT]
-#! Outputs: [note_idx, 0, 0, 0, 0, 0]
+#! Inputs: [tag, aux, note_type, RECIPIENT, PAD(9)]
+#! Outputs: [note_idx, PAD(15)]
 #!
 #! tag is the tag to be included in the note.
 #! aux is the auxiliary metadata to be included in the note.
@@ -515,18 +515,10 @@ end
 export.create_note
     # authenticate that the procedure invocation originates from the account context
     exec.authenticate_account_origin
-    # => [tag, aux, note_type, RECIPIENT]
+    # => [tag, aux, note_type, RECIPIENT, PAD(9)]
 
     exec.tx::create_note
-    # => [note_idx]
-
-    # prepare stack for return. Note: when create_note is called, the stack looks
-    # like [tag, aux, note_type, RECIPIENT, x, X, X], with 16 elements and X might be important data
-    # for the user. Without padding the kernel returns [note_idx, x, X, X, 0, 0, EMPTY_WORD] adding 0's.
-    # To keep the data in position we move 0's to the left between note_idx and the potentially
-    # important first element x.
-    movupw.3 movup.15 movup.15 movup.6
-    # => [note_idx, 0, 0, 0, 0, 0, 0]
+    # => [note_idx, PAD(15)]
 end
 
 #! Adds the ASSET to the note specified by the index.

miden-lib/asm/miden/contracts/wallets/basic.masm

@@ -24,8 +24,12 @@ end
 #! Creates a note which sends the specified asset out of the current account
 #! to the specified recipient.
 #!
-#! Inputs: [ASSET, tag, aux, note_type, RECIPIENT, ...]
-#! Outputs: [note_idx, EMPTY_WORD, EMPTY_WORD, 0, 0, ...]
+#! Note: since this procedure must be only called, the operand stack should be padded to the 16 
+#! elements before being called. See the corresponding issue: 
+#! https://github.com/0xPolygonMiden/miden-base/issues/685
+#!
+#! Inputs: [ASSET, tag, aux, note_type, RECIPIENT, PAD(5)]
+#! Outputs: [note_idx, PAD(15)]
 #!
 #! - ASSET is the non-fungible asset of interest.
 #! - tag is the tag to be included in the note.
@@ -42,211 +46,65 @@ end
 #! - The non-fungible asset is not found in the vault.
 export.send_asset.1
     exec.account::remove_asset
-    # => [ASSET, tag, aux, note_type, RECIPIENT, ...]
+    # => [ASSET, tag, aux, note_type, RECIPIENT, PAD(5)]
 
     # Store the ASSET for later
     loc_storew.0 dropw
-    # => [tag, aux, note_type, RECIPIENT, ...]
-
-    # This procedure is written to be executed with `exec` or `call`. When this
-    # procedure is `call`ed the stack has to be carefully manipulated to avoid
-    # inserting unwanted elements between the user data. The convention is to
-    # ensure the input&output data have the same length. This code pads the
-    # stack so the output stack will be the same length as the input.
-    #
-    # The padding must be added before calling `create_note`, not after. This
-    # is because the VM stack has a minimum size of 16 elements, trying to push
-    # elements after the call to `create_note` would increase the stack in
-    # addition to the minimum 16 elements.
-    push.0 movdn.7 padw movdnw.2 padw movdnw.2
-    # => [tag, aux, note_type, RECIPIENT, 0, EMPTY_WORD, EMPTY_WORD, ...]
+    # => [tag, aux, note_type, RECIPIENT, PAD(9)]
 
     exec.tx::create_note
-    # => [note_idx, 0, EMPTY_WORD, EMPTY_WORD, ...]
+    # => [note_idx, PAD(15) ...]
 
-    padw loc_loadw.0 movup.4
-    # => [note_idx, ASSET, 0, EMPTY_WORD, EMPTY_WORD, ...]
+    movdn.4 loc_loadw.0 movup.4
+    # => [note_idx, ASSET, PAD(11) ...]
 
     exec.tx::add_asset_to_note
-    # => [note_idx, 0, EMPTY_WORD, EMPTY_WORD, ...]
-
-    # prepare the stack for return - stack has 6 elements too many
-    movupw.3 dropw swap drop swap drop
+    # => [note_idx, PAD(15) ...]
 end
 
 #! Creates a note without assets.
 #!
-#! Inputs stack: [tag, aux, note_type, RECIPIENT, ...]
-#! Outputs: [note_idx, 0, 0, EMPTY_WORD, ...]
+#! Note: since this procedure must be only called, the operand stack should be padded to the 16 
+#! elements before being called. See the corresponding issue: 
+#! https://github.com/0xPolygonMiden/miden-base/issues/685
+#!
+#! Inputs stack: [tag, aux, note_type, RECIPIENT, PAD(9)]
+#! Outputs: [note_idx, PAD(15)]
 #!
 #! - tag is the tag to be included in the note.
 #! - aux is the auxiliary data to be included in the note.
 #! - note_type is the note's storage type
 #! - RECIPIENT is the recipient of the note, i.e.,
 #!   hash(hash(hash(serial_num, [0; 4]), script_hash), input_hash)
 export.cteate_note
-    # This procedure is written to be executed with `call`. It means that has to be padded to the 
-    # length of 16 to preserve the stack state after the call. 
-    push.0 movdn.7 padw movdnw.2 padw movdnw.3
-    # => [tag, aux, note_type, RECIPIENT, 0, EMPTY_WORD, EMPTY_WORD, ...]
-
     exec.tx::create_note
     swap drop # TODO: remove this line after bug in the api.masm `create_note` procedure will be 
               # fixed
-    # => [note_idx, 0, 0, 0, EMPTY_WORD, EMPTY_WORD, EMPTY_WORD, ...]
-
-    # prepare the stack for return - stack has 9 elements too many
-    movdn.9 dropw dropw drop
-    # => [note_idx, 0, 0, EMPTY_WORD, ...]
+    # => [note_idx, PAD(15) ...]
 end
 
 #! Add the specified amount of assets to the created note to move them out of the current account to
 #! the specified recipient.
 #!
-#! Inputs stack: [ASSETS_HASH, note_idx, ...]
-#! Advice map: {(ASSETS_HASH, [ASSETS])}
-#! Outputs: [note_idx, EMPTY_WORD, ...]
+#! Note: since this procedure must be only called, the operand stack should be padded to the 16 
+#! elements before being called. See the corresponding issue: 
+#! https://github.com/0xPolygonMiden/miden-base/issues/685
+#!
+#! Inputs stack: [ASSET, note_idx, PAD(11)]
+#! Outputs: [note_idx, PAD(15)]
 #!
-#! - ASSETS_HASH is the sequential hash of the assets which are going to be added to the note.
-#! - [ASSETS] is an array of the assets which are going to be added to the note.
+#! - note_idx is the index of the output note.
+#! - ASSET is the fungible or non-fungible asset of interest.
 #!
 #! Panics:
 #! - The fungible asset is not found in the vault.
 #! - The amount of the fungible asset in the vault is less than the amount to be removed.
 #! - The non-fungible asset is not found in the vault.
 export.move_asset_into_note
-    # check whether ASSETS_HASH is an EMPTY_WORD ([0, 0, 0, 0]). In that case there are no assets 
-    # need to be added to the note
-    padw eqw
-    # => [b, EMPTY_WORD, ASSETS_HASH, note_idx, ...]
-
-    # if there are no assets to add
-    if.true
-        drop swapw dropw movup.4
-        # => [note_idx, EMPTY_WORD, ...]
-    else 
-        # remove redundant word
-        dropw
-        # => [ASSETS_HASH, note_idx, ...]
-
-        # move the assets from the advice map to the advice stack
-        adv.push_mapvaln
-        # => [ASSETS_HASH, note_idx, ...]
-
-        # get the note index to the top of the stack
-        movup.4
-        # => [note_idx, ASSETS_HASH, ...]
-
-        # get the number of assets 
-        # we need to divide the number stored in the advice stack by 4 since this number shows the 
-        # number of felts, not words
-        adv_push.1 div.4
-        # => [num_assets, note_idx, ASSETS_HASH, ...]
-
-        # check if there is an odd number of assets
-        dup is_odd
-        # => [is_odd, num_assets, note_idx, ASSETS_HASH, ...]
-
-        # copy is_odd, it defines if last asset word requires padding
-        dup movdn.3
-        # => [is_odd, num_assets, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # get the even number of assets
-        sub
-        # => [num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # `num_assets_even` will be used as a loop vaiable, so negate it to use add instead of sub 
-        # because the former uses one fewer cycle.
-        neg
-        # [-num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # Prepare the capacity word. For rescue prime optimized the first element is
-        # set to `1` when padding is used and `0` otherwse, this is determined by the
-        # `needs_padding` flag.
-        dup.2 push.0.0.0
-        # => [CAPACITY, -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # set initial hasher state
-        padw padw
-        # => [B, A, CAPACITY, -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        ### Iterate over the assets #######################################################
-        #
-        # Add assets to the note, simultaneously computing their accumulative hash 
-
-        # check loop condition
-        dup.12 neq.0
-        # => [b, B, A, CAPACITY, -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # while num_assets_even != 0
-        while.true
-            # load the assets from advice stack and remove them from the account 
-            adv_loadw exec.account::remove_asset
-            swapw adv_loadw exec.account::remove_asset
-            # => [ASSET_B, ASSET_A, CAPACITY, -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-            # add ASSET_B to the note
-            movup.13 movdn.8
-            dupw movup.12
-            exec.tx::add_asset_to_note
-            # => [note_idx, ASSET_B, ASSET_A, CAPACITY, -num_assets_even, needs_padding, ASSETS_HASH, ...]
-
-            # add ASSET_A to the note
-            movdn.8
-            swapw dupw movup.12
-            exec.tx::add_asset_to_note
-            # => [note_idx, ASSET_A, ASSET_B, CAPACITY, -num_assets_even, needs_padding, ASSETS_HASH, ...]
-
-            movdn.13 swapw
-            # => [ASSET_B, ASSET_A, CAPACITY, -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-            # perform hash iteration
-            hperm
-            # => [HASH_B, HASH_A, CAPACITY', -num_assets_even, note_idx, needs_padding, ASSETS_HASH, ...]
-
-            # update counters
-            movup.12 add.2 movdn.12
-            # => [HASH_B, HASH_A, CAPACITY', -num_assets_even+2, note_idx, needs_padding, ASSETS_HASH, ...]
-
-            # check loop condition
-            dup.12 neq.0
-            # => [b, HASH_B, HASH_A, CAPACITY', -num_assets_even+2, note_idx, needs_padding, ASSETS_HASH, ...]
-        end
-        # => [HASH_B, HASH_A, CAPACITY', 0, note_idx, needs_padding, ASSETS_HASH, ...]
-
-        # if there is still one asset left and we need to perform last permutation iteration
-        movup.14
-        if.true
-            # Rescue Prime Optimized uses overwrite mode, drop `HASH_B`.
-            dropw
-            # => [HASH_A, CAPACITY', 0, note_idx, ASSETS_HASH, ...]
-
-            # load the last asset and remove it from the account
-            adv_loadw exec.account::remove_asset
-            # => [HASH_A', CAPACITY', 0, note_idx, ASSETS_HASH, ...]
-
-            # add last asset to the note
-            dupw movup.13 
-            exec.tx::add_asset_to_note movdn.9
-            # => [HASH_A', CAPACITY', 0, note_idx, ASSETS_HASH, ...]
-
-            # Push padding word (4 cycles)
-            push.1.0.0.0
-            # => [PADDING, HASH_A', CAPACITY', 0, note_idx, ASSETS_HASH, ...]
-
-            # Run RPO permutation (1 cycles)
-            hperm
-            # => [HASH_B, HASH_A'', CAPACITY'', 0, note_idx, ASSETS_HASH, ...]
-        end
-
-        # The RPO result is the middle word (HASH_A''), discard the unused portion of the rate and the 
-        # capacity.
-        dropw swapw dropw
-        # => [ACC_HASH, 0, note_idx, ASSETS_HASH, ...]
+    # remove the asset from the account 
+    exec.account::remove_asset
+    # => [ASSET, note_idx, PAD(11)]
 
-        # check the correctness of the resulting accumulative hash
-        repeat.4 movup.9 end
-        assert_eqw swap
-        # => [note_idx, 0, 0, EMPTY_WORD, ...]
-    end
+    movup.4 exec.tx::add_asset_to_note
+    # => [note_idx, GARBAGE(15) ...]
 end

miden-lib/asm/miden/tx.masm

@@ -55,8 +55,8 @@ end
 
 #! Creates a new note and returns the index of the note.
 #!
-#! Inputs: [tag, aux, note_type, RECIPIENT]
-#! Outputs: [note_idx]
+#! Inputs: [tag, aux, note_type, RECIPIENT, PAD(9)]
+#! Outputs: [note_idx, PAD(15)]
 #!
 #! tag is the tag to be included in the note.
 #! aux is the auxiliary metadata to be included in the note.
@@ -65,11 +65,7 @@ end
 #! note_idx is the index of the crated note.
 export.create_note
     syscall.create_note
-    # => [note_idx, EMPTY_WORD, 0]
-
-    # clear the padding from the kernel response
-    movdn.4 dropw swap drop
-    # => [note_idx]
+    # => [note_idx, PAD(15)]
 end
 
 #! Adds the ASSET to the note specified by the index.