- d = (u32)psx_gpu->viewport_end_x - (u32)viewport_start_x + 1;
- if((u32)psx_gpu->enhancement_x_threshold - d <= 16)
+ w = (u32)psx_gpu->viewport_end_x - (u32)viewport_start_x + 1;
+ d = psx_gpu->enhancement_x_threshold - w;
+ if(-16 <= d && d <= 16)