anza-xyz · samkim-crypto · Aug 26, 2025 · Aug 22, 2025 · Aug 26, 2025
diff --git a/bn254/src/addition.rs b/bn254/src/addition.rs
@@ -0,0 +1,136 @@
+use crate::PodG1;
+pub use target_arch::*;
+
+pub(crate) mod consts {
+    use crate::LE_FLAG;
+
+    /// Input length for the add operation.
+    pub const ALT_BN128_ADDITION_INPUT_LEN: usize = 128;
+    /// Output length for the add operation.
+    pub const ALT_BN128_ADDITION_OUTPUT_LEN: usize = 64;
+
+    pub const ALT_BN128_ADD: u64 = 0;
+    pub const ALT_BN128_SUB: u64 = 1;
+    pub const ALT_BN128_ADD_LE: u64 = ALT_BN128_ADD | LE_FLAG;
+    pub const ALT_BN128_SUB_LE: u64 = ALT_BN128_SUB | LE_FLAG;
+}
+
+#[cfg(not(target_os = "solana"))]
+pub(crate) mod target_arch {
+    use {
+        super::{consts::*, PodG1},
+        crate::{
+            target_arch::{convert_endianness_64, Endianness, G1},
+            AltBn128Error,
+        },
+        ark_serialize::{CanonicalSerialize, Compress},
+    };
+
+    #[inline(always)]
+    pub fn alt_bn128_addition(input: &[u8]) -> Result<Vec<u8>, AltBn128Error> {
+        alt_bn128_apply_addition(input, Endianness::BE)
+    }
+
+    #[inline(always)]
+    pub fn alt_bn128_addition_le(input: &[u8]) -> Result<Vec<u8>, AltBn128Error> {
+        alt_bn128_apply_addition(input, Endianness::LE)
+    }
+
+    fn alt_bn128_apply_addition(
+        input: &[u8],
+        endianness: Endianness,
+    ) -> Result<Vec<u8>, AltBn128Error> {
+        match endianness {
+            Endianness::BE => {
+                if input.len() > ALT_BN128_ADDITION_INPUT_LEN {
+                    return Err(AltBn128Error::InvalidInputData);
+                }
+            }
+            Endianness::LE => {
+                if input.len() != ALT_BN128_ADDITION_INPUT_LEN {
+                    return Err(AltBn128Error::InvalidInputData);
+                }
+            }
+        }
+
+        let mut input = input.to_vec();
+        match endianness {
+            Endianness::BE => input.resize(ALT_BN128_ADDITION_INPUT_LEN, 0),
+            Endianness::LE => (),
+        }
+
+        let p: G1 = match endianness {
+            Endianness::BE => PodG1::from_be_bytes(&input[..64])?.try_into()?,
+            Endianness::LE => PodG1::from_le_bytes(&input[..64])?.try_into()?,
+        };
+
+        let q: G1 = match endianness {
+            Endianness::BE => PodG1::from_be_bytes(&input[64..])?.try_into()?,
+            Endianness::LE => PodG1::from_le_bytes(&input[64..])?.try_into()?,
+        };
+
+        #[allow(clippy::arithmetic_side_effects)]
+        let result_point = p + q;
+
+        let mut result_point_data = [0u8; ALT_BN128_ADDITION_OUTPUT_LEN];
+        let result_point_affine: G1 = result_point.into();
+        result_point_affine
+            .x
+            .serialize_with_mode(&mut result_point_data[..32], Compress::No)
+            .map_err(|_| AltBn128Error::InvalidInputData)?;
+        result_point_affine
+            .y
+            .serialize_with_mode(&mut result_point_data[32..], Compress::No)
+            .map_err(|_| AltBn128Error::InvalidInputData)?;
+
+        match endianness {
+            Endianness::BE => Ok(convert_endianness_64(&result_point_data[..])),
+            Endianness::LE => Ok(result_point_data.to_vec()),
+        }
+    }
+}
+
+#[cfg(target_os = "solana")]
+pub(crate) mod target_arch {
+    use {super::consts, crate::AltBn128Error, solana_define_syscall::definitions as syscalls};
+
+    pub fn alt_bn128_addition(input: &[u8]) -> Result<Vec<u8>, AltBn128Error> {
+        if input.len() > consts::ALT_BN128_ADDITION_INPUT_LEN {
+            return Err(AltBn128Error::InvalidInputData);
+        }
+        let mut result_buffer = [0; consts::ALT_BN128_ADDITION_OUTPUT_LEN];
+        let result = unsafe {
+            syscalls::sol_alt_bn128_group_op(
+                consts::ALT_BN128_ADD,
+                input as *const _ as *const u8,
+                input.len() as u64,
+                &mut result_buffer as *mut _ as *mut u8,
+            )
+        };
+
+        match result {
+            0 => Ok(result_buffer.to_vec()),
+            _ => Err(AltBn128Error::UnexpectedError),
+        }
+    }
+
+    pub fn alt_bn128_addition_le(input: &[u8]) -> Result<Vec<u8>, AltBn128Error> {
+        if input.len() != consts::ALT_BN128_ADDITION_INPUT_LEN {
+            return Err(AltBn128Error::InvalidInputData);
+        }
+        let mut result_buffer = [0; consts::ALT_BN128_ADDITION_OUTPUT_LEN];
+        let result = unsafe {
+            syscalls::sol_alt_bn128_group_op(
+                consts::ALT_BN128_ADD_LE,
+                input as *const _ as *const u8,
+                input.len() as u64,
+                &mut result_buffer as *mut _ as *mut u8,
+            )
+        };
+
+        match result {
+            0 => Ok(result_buffer.to_vec()),
+            _ => Err(AltBn128Error::UnexpectedError),
+        }
+    }
+}
diff --git a/bn254/src/compression.rs b/bn254/src/compression.rs
@@ -7,12 +7,13 @@ pub mod prelude {
 use thiserror::Error;
 
 mod consts {
+    use crate::LE_FLAG;
+
     pub const ALT_BN128_G1_COMPRESS: u64 = 0;
     pub const ALT_BN128_G1_DECOMPRESS: u64 = 1;
     pub const ALT_BN128_G2_COMPRESS: u64 = 2;
     pub const ALT_BN128_G2_DECOMPRESS: u64 = 3;
 
-    const LE_FLAG: u64 = 0x80;
     pub const ALT_BN128_G1_COMPRESS_LE: u64 = ALT_BN128_G1_COMPRESS | LE_FLAG;
     pub const ALT_BN128_G1_DECOMPRESS_LE: u64 = ALT_BN128_G1_DECOMPRESS | LE_FLAG;
     pub const ALT_BN128_G2_COMPRESS_LE: u64 = ALT_BN128_G2_COMPRESS | LE_FLAG;