//
// PTX kernel stub: l2norm-kernel-v1
// L2 norm kernel — Euclidean vector length
// Equation l2norm: ||x|| = sqrt(Σ x_i²)
//

.version 8.5
.target sm_90
.address_size 64

.visible .entry l2norm(
    .param .u64 input,
    .param .u64 output,
    .param .u32 n
)
{
    .reg .u32 %tid, %n;
    .reg .u64 %in_ptr, %out_ptr;
    .reg .f32 %val, %acc;

    ld.param.u64 %in_ptr, [input];
    ld.param.u64 %out_ptr, [output];
    ld.param.u32 %n, [n];

    mov.u32 %tid, %ctaid.x;
    mad.lo.u32 %tid, %tid, %ntid.x, %tid.x;

    // Phase 1: square
    // Compute x_i²
    // Invariant: sq_i ≥ 0

    // Phase 2: sum
    // Accumulate Σ sq_i
    // Invariant: total ≥ 0

    // Phase 3: sqrt
    // Compute sqrt(total)
    // Invariant: result ≥ 0

    // Proof obligations:
    //   [bound] Non-negative
    //   [invariant] Homogeneity
    //   [invariant] Zero vector yields zero
    //   [equivalence] SIMD matches scalar

    ret;
}
