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uphl     inc  h                 
         ld   a,h               
         and  7                 
         ret  nz                
         ld   a,l               
         add  a,32              
         ld   l,a               
         ld   a,h               
         ret  c                 
         sub  8                 
         ld   h,a               
         ret

Slower alternative:

uphl      ld   a,h               
          dec  h                 
          and  7                 
          ret  nz                
          ld   a,l               
          sub  32                
          ld   l,a               
          ld   a,h               
          jr   c,uphl2           
          add  a,8               
          ld   h,a               
uphl2     cp   64                
          ret  nc                
          ld   h,87               
          ret

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