User guide

SmartBook for Renesas R8C/Tiny Microcontrollers

www.MightyMicons.com

DADD instructions do an arithmetic addition on BCD

coded data and keeps the results in the destination.

DADC instructions do the similar operation on the two

data along with the carry flag.

Then, the devices support decimal subtraction on two BCD

coded data using DSUB instructions. DSUBB instructions

do the same operations along with the carry. Instructions

are available for both 8-bit and 16-bit operands.

Other microcontrollers manage these decimal operations using many

instructions. Here, availability of these instructions makes the designers

happy during their application development.

Apart from the above mentioned instructions, the R8C/Tiny devices sport many

useful special instructions which enable the designers embed math intensive

operations within their applications without much pain.

3.11 Repeat Multiple and Addition (RMPA):

This instruction performs sum of products calculations with the multiplicand

address indicated by A0 register, the multiplier address indicated by A1 and the

R3 register keeping the count of operation. The calculations continue till R3

becomes zero and the result is available in R2R0.

This sum of product operation gets executed in every nine clocks. This instruction

gives the micon the MAC power that is available only in the regular and high

priced DSP devices. In the high speed DSP devices, the MAC instruction requires

only a single clock cycle to finish operation. However, the R8C/Tiny devices take

more time to do the same operation. In the digital signal processing, you need to

finish all the required operations before you get the next sample in a loop to get

the required results. Even though the R8C/Tiny devices take more clock cycles to

finish the signal processing operations, the devices can be used on many low

speed signals without any problems.



 DADD instructions do

an arithmetic addition

on BCD coded data and

keeps the results in the

destination.



 The

Sum of Product

(RMPA) operation gives the micon the

MAC power that is available only

in the regular and high priced

DSP devices. This operation

gets executed in every

nine clocks.