### Compilation failed:

error: 2: variables of type 'uint' may not be uniform
uniform uint b;
^^^^^^^^^^^^^^
error: 3: 'main' must return: 'vec4', 'float4', or 'half4'
void main() {
^^^^^^^^^^^
error: 4: unknown identifier 'sk_FragColor'
    sk_FragColor.x = half(findMSB(a));
    ^^^^^^^^^^^^
error: 4: unknown identifier 'findMSB'
    sk_FragColor.x = half(findMSB(a));
                          ^^^^^^^
error: 5: unknown identifier 'sk_FragColor'
    sk_FragColor.y = half(findMSB(b));
    ^^^^^^^^^^^^
error: 5: unknown identifier 'findMSB'
    sk_FragColor.y = half(findMSB(b));
                          ^^^^^^^
6 errors