Arithmetic logic unit (alu) block, 1 overview – NEC PD17062 User Manual
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48
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PD17062
7. ARITHMETIC LOGIC UNIT (ALU) BLOCK
7.1 OVERVIEW
Fig. 7-1 is an overview of the ALU block.
As shown in Fig. 7-1, the ALU block consists of the ALU, temporary storage registers A and B, program
status word, decimal conversion circuit, and data memory address controller.
The ALU performs arithmetic and logic operations on the 4-bit data in the data memory and performs
discrimination, comparison, rotation, and transfer.
Fig. 7-1 Overview of the ALU Block
Data memory
Data bus
Program status
word
Address
controller
Temporary
storage
register A
Temporary
storage
register B
Indexing memory
pointer
Detecting a carry,
borrow, or zero
Setting decimal
calculation or result
storage
ALU
• Arithmetic operation
• Logic operation
• Bit discrimination
• Comparative
discrimination
• Rotation
• Transfer
Decimal conversion