CHAPTER 16 MULTIPLIER/DIVIDER
User’s Manual U16899EJ2V0UD
349
The functions of MDA0 when an operation is executed are shown in the table below.
Table 16-2. Functions of MDA0 During Operation Execution
DMUSEL0 Operation
Mode
Setting Operation
Result
0 Division
mode
Dividend
Division result (quotient)
1
Multiplication mode
Higher 16 bits: 0, Lower 16
bits: Multiplier A
Multiplication result
(product)
The register configuration differs between when multiplication is executed and when division is executed, as
follows.
•
Register configuration during multiplication
<Multiplier A>
<Multiplier B>
<Product>
MDA0 (bits 15 to 0)
×
MDB0 (bits 15 to 0) = MDA0 (bits 31 to 0)
•
Register configuration during division
<Dividend>
<Divisor>
<Quotient>
<Remainder>
MDA0 (bits 31 to 0)
÷
MDB0 (bits 15 to 0) = MDA0 (bits 31 to 0) … SDR0 (bits 15 to 0)
MDA0 fetches the calculation result as soon as the clock is input, when bit 7 (DMUE) of multiplier/divider
control register 0 (DMUC0) is set to 1.
MDA0H and MDA0L can be set by an 8-bit or 16-bit memory manipulation instruction.
RESET input clears this register to 0000H.
(3) Multiplication/division data register B0 (MDB0)
MDB0 is a register that stores a 16-bit multiplier B in the multiplication mode and a 16-bit divisor in the
division mode.
This register can be set by an 8-bit or 16-bit memory manipulation instruction.
RESET input clears this register to 0000H.
Figure 16-4. Format of Multiplication/Division Data Register B0 (MDB0)
Address: FF66H, FF67H After reset: 0000H R/W
Symbol
FF67H (MDB0H)
FF66H (MDB0L)
MDB0
MDB
015
MDB
014
MDB
013
MDB
012
MDB
011
MDB
010
MDB
009
MDB
008
MDB
007
MDB
006
MDB
005
MDB
004
MDB
003
MDB
002
MDB
001
MDB
000
Cautions 1. Do not change the value of MDB0 during operation processing (while bit 7 (DMUE) of
multiplier/divider control register 0 (DMUC0) is 1). Even in this case, the operation is
executed, but the result is undefined.
2. Do not clear MDB0 to 0000H in the division mode. If set, undefined operation results are
stored in MDA0 and SDR0.
Содержание MuPD78F0132H
Страница 2: ...User s Manual U16899EJ2V0UD 2 MEMO ...