This is a typical game shader snippet for lighting/specular. It doesn't conserve energy, so I don't think it's proper PBR. It can probably use a few tweaks.

gameShaderLighting.hlsl

// shadertype=hlsl

float G1V(float NdotV, float k)
{
    return 1.0f / (NdotV * (1.0f - k) + k);
}

float SchlickFresnel(float u)
{
    float m = clamp(1 - u, 0, 1);
    float m2 = m*m;
    return m2*m2*m; // pow(m,5)
}


struct lightOut
{
    float   Specular;
    float3  Color;
};

lightOut smlBRDF(float3 L, float3 V, float3 N, float3 Albedo)
{
	lightOut OUT = (lightOut)0;
	OUT.Color = float3(0.0f, 0.0f, 0.0f);
	OUT.Specular = 0.0f;

	float alpha = roughness * roughness;

	float3 H = normalize( L + V );
	
	float NdotL = saturate( dot( N, L ) );
	float NdotV = saturate( dot( N, V ) );
	float NdotH = saturate( dot( N, H ) );
	float LdotH = saturate( dot( L, H ) );

	float F, D, vis;

	// V ... calc visability term
	float k = alpha / 2.0f;
	vis = G1V(NdotL, k) * G1V(NdotV, k);

	float3 Cdlin = Albedo.rgb; // pass in color already converted to linear
  	float Cdlum = 0.3f * Cdlin[0] + 0.6f * Cdlin[1] + 0.1f * Cdlin[2]; // luminance approx.

  	float3 Ctint = Cdlum > 0.0f ? Cdlin/Cdlum : 1.0f.xxx; // normalize lum. to isolate hue+sat
  	float3 Cspec0 = lerp(specular * 0.08f * lerp(1.0f.xxx, Ctint, specularTint), Cdlin, metalness);
  	float3 Csheen  = lerp(1.0f.xxx, Ctint, sheenTint);

	// D
	float alphaSqr = alpha*alpha;
	float denom = NdotH * NdotH * (alphaSqr-1.0f) + 1.0f;
	D = alphaSqr / (PI * denom * denom);

	// F
	float LdotH5 = pow(1.0f-LdotH, 5.0f);
	float F0 = SchlickFresnel(LdotH);
	F = F0 + (1.0f-F0) * (LdotH5);
	float3 Fs = lerp(Cspec0, 1.0f.xxx, F);
    
	float specularBRDF = D * Fs * vis * NdotL;
	
	OUT.Specular = specularBRDF * Cspec0;

  	OUT.Color = INV_PI * ( 1.0 - metalness ) * Cdlin;
  	OUT.Color *= NdotL;

  	return OUT;
}