NEC 78K0 User Manual page 421

(2) Multiplication/division data register A0 (MDA0H, MDA0L)
MDA0 is a 32-bit register that sets a 16-bit multiplier A in the multiplication mode and a 32-bit dividend in the
division mode, and stores the 32-bit result of the operation (higher 16 bits: MDA0H, lower 16 bits: MDA0L).
Figure 18-3. Format of Multiplication/Division Data Register A0 (MDA0H, MDA0L)
Address: FF62H, FF63H, FF64H, FF65H
Symbol FF65H (MDA0HH)
MDA0H MDA MDA MDA
031 030 029
Symbol FF63H (MDA0LH)
MDA0L MDA MDA MDA
015 014 013
Cautions 1. MDA0H is cleared to 0 when an operation is started in the multiplication mode (when
multiplier/divider control register 0 (DMUC0) is set to 81H).
2. Do not change the value of MDA0 during operation processing (while bit 7 (DMUE) of
multiplier/divider control register 0 (DMUC0) is 1).
executed, but the result is undefined.
3. The value read from MDA0 during operation processing (while DMUE is 1) is not
guaranteed.
CHAPTER 18 MULTIPLIER/DIVIDER
After reset: 0000H, 0000H
MDA MDA MDA MDA MDA
028 027 026 025 024
MDA MDA MDA MDA MDA
012 011 010 009 008
*
User's Manual U15947EJ2V0UD
R/W
FF64H (MDA0HL)
MDA MDA MDA MDA MDA
023 022 021 020 019
FF62H (MDA0LL)
MDA MDA MDA MDA MDA
007 006 005 004 003
Even in this case, the operation is
MDA MDA MDA
018 017 016
MDA MDA MDA
002 001 000
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