fix typo in block read
fix typo in block read

lunixbochs/glshim,lunixbochs/glshim,seandepagnier/glshim,lunixbochs/glshim,seandepagnier/glshim,RobertoMalatesta/glshim,seandepagnier/glshim,RobertoMalatesta/glshim,RobertoMalatesta/glshim,seandepagnier/glshim,RobertoMalatesta/glshim,lunixbochs/glshim