"""BF16 text activation math shared by pointwise and GEMM epilogues."""

import cutlass
import cutlass.cute as cute

from clef_vision_norm import mul_rn


@cute.jit
def silu_bf16(value):
    """Input is BF16-rounded; validate the complete finite BF16 domain on SM90."""
    denominator = 1.0 + cute.math.exp(-value, fastmath=True)
    activated = cutlass.Float32(0)
    if value > -87.0:
        inverse = cute.math.rcp(denominator, fastmath=True)
        activated = mul_rn(value, inverse)
    else:
        # Preserve tiny negative activations when the reciprocal would flush to zero.
        activated = value / denominator
    return activated.to(cutlass.BFloat16)