//
// x86-64 AVX2 stub: l2norm-kernel-v1
// L2 norm kernel — Euclidean vector length
// Equation l2norm: ||x|| = sqrt(Σ x_i²)
//

.intel_syntax noprefix
.text
.globl l2norm_avx2
.p2align 4

l2norm_avx2:
    push rbp
    mov rbp, rsp
    // rdi = input ptr, rsi = output ptr, edx = n

    // AVX2 registers: ymm x 16
    vxorps ymm0, ymm0, ymm0
    vxorps ymm1, ymm1, ymm1
    vxorps ymm2, ymm2, ymm2
    vxorps ymm3, ymm3, ymm3

    // 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

    pop rbp
    ret
