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feat!: instruction hash only puts digest on stack
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Notably, the top of the stack in not polluted with spurious 0s.

BREAKING CHANGE: executing instruction `hash` shrinks the stack by 5
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@jan-ferdinand
jan-ferdinand committed Oct 30, 2023
1 parent 6215c10 commit 2e37fb2
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Showing 7 changed files with 221 additions and 158 deletions.
2 changes: 1 addition & 1 deletion opcodes.py
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ def in_bucket(instruction_bucket, instruction):
return instruction in [Instruction.Push, Instruction.Dup, Instruction.Swap, Instruction.Call]
if instruction_bucket == InstructionBucket.ShrinkStack:
return instruction in [Instruction.Pop, Instruction.Skiz, Instruction.Assert, Instruction.WriteMem, Instruction.WriteIo,
Instruction.Add, Instruction.Mul, Instruction.Eq, Instruction.XbMul,
Instruction.Add, Instruction.Mul, Instruction.Eq, Instruction.XbMul, Instruction.Hash,
Instruction.Lt, Instruction.And, Instruction.Xor, Instruction.Pow]
if instruction_bucket == InstructionBucket.U32:
return instruction in [Instruction.Lt, Instruction.And, Instruction.Xor, Instruction.Log2Floor,
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24 changes: 11 additions & 13 deletions triton-vm/src/example_programs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -138,39 +138,38 @@ fn merkle_tree_authentication_path_verify() -> Program {
push -1 add write_mem pop // decrease number of authentication paths left to check
// stack: [* r4 r3 r2 r1 r0]
call get_idx_and_leaf
// stack: [* r4 r3 r2 r1 r0 idx d4 d3 d2 d1 d0 0 0 0 0 0]
// stack: [* r4 r3 r2 r1 r0 idx l4 l3 l2 l1 l0]
call traverse_tree
// stack: [* r4 r3 r2 r1 r0 idx>>1 - - - - - - - - - -]
// stack: [* r4 r3 r2 r1 r0 1 d4 d3 d2 d1 d0]
call assert_tree_top
// stack: [* r4 r3 r2 r1 r0]
recurse // check next AP

// subroutine: read index & hash leaf
// stack before: [*]
// stack after: [* idx d4 d3 d2 d1 d0 0 0 0 0 0]
// stack after: [* idx l4 l3 l2 l1 l0]
get_idx_and_leaf:
read_io // read node index
read_io read_io read_io read_io read_io // read leaf's value
push 0 push 0 push 0 push 0 push 0 // pad for instruction divine_sibling
return

// subroutine: go up tree
// stack before: [* idx - - - - - - - - - -]
// stack after: [* idx>>1 - - - - - - - - - -]
// stack before: [* r4 r3 r2 r1 r0 idx l4 l3 l2 l1 l0]
// stack after: [* r4 r3 r2 r1 r0 1 d4 d3 d2 d1 d0]
traverse_tree:
dup 10 push 1 eq skiz return // break loop if node index is 1
dup 5 push 1 eq skiz return // break loop if node index is 1
push 0 push 0 push 0 push 0 push 0 // prepare for instruction `divine_sibling`
divine_sibling hash recurse // move up one level in the Merkle tree

// subroutine: compare digests
// stack before: [* r4 r3 r2 r1 r0 idx a b c d e - - - - -]
// stack before: [* r4 r3 r2 r1 r0 1 d4 d3 d2 d1 d0]
// stack after: [* r4 r3 r2 r1 r0]
assert_tree_top:
pop pop pop pop pop // remove unnecessary “0”s from hashing
// stack: [* r4 r3 r2 r1 r0 idx a b c d e]
// stack: [* r4 r3 r2 r1 r0 1 d4 d3 d2 d1 d0]
swap 1 swap 2 swap 3 swap 4 swap 5
// stack: [* r4 r3 r2 r1 r0 a b c d e idx]
// stack: [* r4 r3 r2 r1 r0 d4 d3 d2 d1 d0 1]
assert // ensure the entire path was traversed
// stack: [* r4 r3 r2 r1 r0 a b c d e]
// stack: [* r4 r3 r2 r1 r0 d4 d3 d2 d1 d0]
assert_vector // actually compare to root of tree
pop pop pop pop pop // clean up stack, leave only one root
return
Expand Down Expand Up @@ -545,7 +544,6 @@ pub(crate) fn calculate_new_mmr_peaks_from_append_with_safe_lists() -> Program {
// Stack: _ old_leaf_count_hi old_leaf_count_lo rll *auth_path *peaks *peaks [digest (new_hash)] [digests (previous_peak)]

hash
pop pop pop pop pop
// Stack: _ old_leaf_count_hi old_leaf_count_lo rll *auth_path *peaks *peaks [digests (new_peak)]

call tasm_list_safe_u32_push_digest
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37 changes: 17 additions & 20 deletions triton-vm/src/instruction.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -170,16 +170,16 @@ impl<Dest: PartialEq + Default> AnInstruction<Dest> {
Halt => 0,
ReadMem => 40,
WriteMem => 26,
Hash => 48,
DivineSibling => 56,
AssertVector => 64,
SpongeInit => 72,
SpongeAbsorb => 80,
SpongeSqueeze => 88,
Add => 34,
Mul => 42,
Invert => 96,
Eq => 50,
Hash => 34,
DivineSibling => 48,
AssertVector => 56,
SpongeInit => 64,
SpongeAbsorb => 72,
SpongeSqueeze => 80,
Add => 42,
Mul => 50,
Invert => 88,
Eq => 58,
Split => 4,
Lt => 6,
And => 14,
Expand All @@ -188,12 +188,12 @@ impl<Dest: PartialEq + Default> AnInstruction<Dest> {
Pow => 30,
DivMod => 20,
PopCount => 28,
XxAdd => 104,
XxMul => 112,
XInvert => 120,
XbMul => 58,
ReadIo => 128,
WriteIo => 66,
XxAdd => 96,
XxMul => 104,
XInvert => 112,
XbMul => 66,
ReadIo => 120,
WriteIo => 74,
}
}

Expand Down Expand Up @@ -334,7 +334,7 @@ impl<Dest: PartialEq + Default> AnInstruction<Dest> {
Halt => 0,
ReadMem => 1,
WriteMem => -1,
Hash => 0,
Hash => -5,
DivineSibling => 0,
AssertVector => 0,
SpongeInit => 0,
Expand Down Expand Up @@ -522,7 +522,6 @@ pub enum InstructionBit {
IB4,
IB5,
IB6,
IB7,
}

impl Display for InstructionBit {
Expand All @@ -542,7 +541,6 @@ impl From<InstructionBit> for usize {
IB4 => 4,
IB5 => 5,
IB6 => 6,
IB7 => 7,
}
}
}
Expand All @@ -559,7 +557,6 @@ impl TryFrom<usize> for InstructionBit {
4 => Ok(IB4),
5 => Ok(IB5),
6 => Ok(IB6),
7 => Ok(IB7),
_ => Err(format!(
"Index {bit_index} is out of range for `InstructionBit`."
)),
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2 changes: 1 addition & 1 deletion triton-vm/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -525,7 +525,7 @@ mod tests {
// Program proves the knowledge of a hash preimage
let program = triton_program!(
divine divine divine divine divine
hash pop pop pop pop pop
hash
push 09456474867485907852
push 12765666850723567758
push 08551752384389703074
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