ziskos 1.1.0-alpha

Guest runtime and entrypoint for programs targeting the ZisK zkVM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

//! syscall_bn254_complex_sub system call interception

#[cfg(zisk_guest)]
use crate::ziskos_syscall;

#[cfg(zisk_guest)]
use core::arch::asm;

use super::complex::SyscallComplex256;

#[derive(Debug)]
#[repr(C)]
pub struct SyscallBn254ComplexSubParams<'a> {
    pub f1: &'a mut SyscallComplex256,
    pub f2: &'a SyscallComplex256,
}

/// Performs the subtraction of two complex field elements on a complex extension of the BN254 base field curve,
/// storing the result in the first field element.
///
/// `Bn254ComplexSub` operates on two field elements, each with two coordinates of 256 bits.
/// Each coordinate is represented as an array of four `u64` elements.
/// The syscall takes as a parameter the address of a structure containing field elements `f1` and `f2`.
/// The result of the subtraction is stored in `f1`.
///
/// ### Safety
///
/// The caller must ensure that the data is aligned to a 64-bit boundary.
///
/// The `f1` and `f2` coordinates are not required to be canonical representatives of elements
/// in the BN254 base field.
///
/// The resulting field element will have both coordinates reduced to canonical representatives
/// in the range of the BN254 base field.
#[allow(unused_variables)]
#[cfg_attr(not(feature = "hints"), no_mangle)]
#[cfg_attr(feature = "hints", export_name = "hints_syscall_bn254_complex_sub")]
pub extern "C" fn syscall_bn254_complex_sub(
    params: &mut SyscallBn254ComplexSubParams,
    #[cfg(feature = "hints")] hints: &mut Vec<u64>,
) {
    #[cfg(zisk_guest)]
    ziskos_syscall!(zisk_definitions::SYSCALL_BN254_COMPLEX_SUB_ID, params);
    #[cfg(not(zisk_guest))]
    {
        let f1 = [params.f1.x, params.f1.y].concat().try_into().unwrap();
        let f2 = [params.f2.x, params.f2.y].concat().try_into().unwrap();
        let mut f3: [u64; 8] = [0; 8];
        zisk_precomp_helpers::bn254_complex_sub(&f1, &f2, &mut f3);
        params.f1.x.copy_from_slice(&f3[0..4]);
        params.f1.y.copy_from_slice(&f3[4..8]);
        #[cfg(feature = "hints")]
        {
            hints.extend_from_slice(&f3);
        }
    }
}