FUJITSU FR family 32-bit microcontroller instruction manuel CM71-00101-5E - Manual (Page 53)

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CHAPTER 3 REGISTER DESCRIPTIONS
3.3.6 Multiplication/Division Register (MD)
The multiplication/division register (MD) is a 64-bit register used to contain the result of
multiplication operations, as well as the dividend and result of division operations.
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Overview of the Multiplication/Division Register
The multiplication/division register (MD) is a register used to contain the result of multiplication
operations, as well as the dividend and result of division operations. The products of multiplication are
stored in the "MD" in 64-bit format. In division operations, the dividend must first be placed in the lower
32 bits of the "MD" beforehand. Then as the division process is executed, the remainder is placed in the
higher 32 bits of the "MD", and the quotient in the lower 32 bits.
Figure 3.3-15 shows an example of the use of the "MD" in multiplication, and Figure 3.3-16 shows an
example of division.
Figure 3.3-15 Sample Operation of "MD" in Multiplication
Figure 3.3-16 Sample Operation of "MD" in Division
Before execution of instruction MUL R00,R01
12345678 H
76543210 H
R00
R01
???????????????? H MD
After execution of instruction MUL R00,R01
12345678 H
76543210 H
R00
R01
086A1C970B88D780 H MD
Before execution of stepwise division
12345678 H
Using R00
R00
????????76543210 H MD
After execution of stepwise division
12345678 H R00
091A264000000006 H MD