Chapter 14 multiplier, 1 multiplier function, 2 multiplier configuration – NEC PD78F9488 User Manual
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User’s Manual U15331EJ4V1UD
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CHAPTER 14 MULTIPLIER
14.1 Multiplier Function
The multiplier has the following function.
• Calculation of 8 bits × 8 bits = 16 bits
14.2 Multiplier Configuration
(1) 16-bit multiplication result storage register 0 (MUL0)
This register stores the 16-bit result of multiplication.
This register holds the result of multiplication after 16 CPU clocks have elapsed.
MUL0 is set with a 16-bit memory manipulation instruction.
RESET input makes this register undefined.
Caution Although this register is manipulated with a 16-bit memory manipulation instruction, it can
also be manipulated with an 8-bit memory manipulation instruction. When using an 8-bit
memory manipulation instruction, however, access the register by means of direct
addressing.
(2) Multiplication data registers A and B (MRA0 and MRB0)
These are 8-bit multiplication data storage registers. The multiplier multiplies the values of MRA0 and MRB0.
MRA0 and MRB0 are set with an 8-bit memory manipulation instructions.
RESET input makes these registers undefined.
Figure 14-1 shows the block diagram of the multiplier.