Chapter 12 Multiplier; Multiplier Function; Multiplier Configuration - NEC 78K0S/KB1+ User Manual

12.1 Multiplier Function

The multiplier has the following function.
• Calculation of 8 bits × 8 bits = 16 bits

12.2 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 can be read by a 16-bit memory manipulation instruction.
Reset signal generation makes MUL0 undefined.
Caution Although this register is manipulated with a 16-bit memory manipulation instruction, it can
be also 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 can be written by an 8-bit memory manipulation instruction.
Reset signal generation makes these registers undefined.
Figure 12-1 shows the block diagram of the multiplier.

CHAPTER 12 MULTIPLIER

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