//
// PTX kernel stub: relu-kernel-v1
// ReLU activation — rectified linear unit
// Equation relu: y_i = max(0, x_i)
//

.version 8.5
.target sm_90
.address_size 64

.visible .entry relu(
    .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: compare
    // Compare each x_i against zero
    // Invariant: mask_i = (x_i > 0)

    // Phase 2: select
    // Select x_i if positive, else zero
    // Invariant: y_i = mask_i ? x_i : 0

    // Proof obligations:
    //   [invariant] Non-negativity
    //   [bound] Output bounded below by zero
    //   [idempotency] Idempotent application
    //   [equivalence] SIMD matches scalar

    ret;
}
