Arithmetic and logic unit

An arithmetic and logic unit ("ALU") of a microprocessor is subdivided into two blocks corresponding respectively to bits 0-15 and 16-31, the first block being of the type with simple carry propagation ("manchester carry ripple") and the second being of the type with carry selection ("carry select"), each of the blocks itself being subdivided into sub-blocks each of four bits, sub blocks each equipped with a carry skip device ("carry skip") relating to the sub block. With each four bit sub-block is associated a circuit (LOOBIT, LOOBIS) for carrying out the carry skip and regenerating the levels. UNE UNITE ARITHMETIQUE ET LOGIQUE ("ALU") DE MICROPROCESSEUR EST SUBDIVISEE EN DEUX BLOCS CORRESPONDANT AUX BITS RESPECTIVEMENT 0-15 ET 16-31, LE PREMIER BLOC ETANT DU TYPE A SIMPLE PROPAGATION DE RETENUE ("MANCHESTER CARRY RIPPLE") ET LE DEUXIEME ETANT DU TYPE A SELECTION DE RETENUE ("CARRY SELECT"), CHACUN DES BLOCS ETANT LUI-MEME SUBDIVISE EN SOUS-BLOCS DE QUATRE BITS CHACUN, SOUS-BLOCS MUNIS CHACUN D'UN DISPOSITIF DE SAUT DE RETENUE ("CARRY SKIP") PORTANT SUR LE SOUS-BLOC. A CHAQUE SOUS-BLOC DE QUATRE BITS EST ASSOCIE UN CIRCUIT (LOOBIT, LOOBIS) POUR REALISER LE SAUT DE RETENUE ET REGENERER LES NIVEAUX.