Built-In Multiplier/Accumulator; Built-In Single-Precision Fpu; Built-In Flash Memory And Ram - Renesas M32R/ECU Series User Manual

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1.1.2 Built-in Multiplier/Accumulator

(1) Built-in high-speed multiplier
• The M32R-FPU contains a 32 bits × 16 bits high-speed multiplier which enables the M32R-FPU to
execute a 32 bits × 32 bits integral multiplication instruction in three CPUCLK periods.
(2) DSP-comparable sum-of-products instructions
• The M32R-FPU supports the following four types of sum-of-products calculation instructions (or multipli-
cation instructions) which each can be executed in one CPUCLK period using a 56-bit accumulator.
(1) 16 high-order bits of register × 16 high-order bits of register
(2) 16 low-order bits of register × 16 low-order bits of register
(3) All 32 bits of register × 16 high-order bits of register
(4) All 32 bits of register × 16 low-order bits of register
• The M32R-FPU has some special instructions to round the value stored in the accumulator to 16 or
32 bits or shift the accumulator value before storing in a register to have its digits adjusted. Because
these instructions too are executed in one CPUCLK period, when used in combination with high-
speed data transfer instructions such as Load & Address Update or Store & Address Update, they
enable the M32R-FPU to exhibit superior data processing capability comparable to that of a DSP.

1.1.3 Built-in Single-precision FPU

• The M32R-FPU supports single-precision floating-point arithmetic fully compliant with IEEE 754 stan-
dards. Specifically, five exceptions specified in IEEE 754 standards (Inexact, Underflow, Division by
Zero, Overflow and Invalid Operation) and four rounding modes (round to nearest, round toward 0,
round toward + Infinity and round toward – Infinity) are supported. What's more, because general-
purpose registers are used to perform floating-point arithmetic, the overhead associated with trans-
ferring the operand data can be reduced.

1.1.4 Built-in Flash Memory and RAM

• The 32180 contains a RAM that can be accessed with zero wait state, allowing to design a high-speed
embedded system.
• The internal flash memory can be written to while mounted on a printed circuit board (on-board writ-
ing). Use of flash memory facilitates development work, because the chip used at the development
stage can be used directly in mass-production, allowing for a smooth transition from prototype to
mass-production without the need to change the printed circuit board.
• The internal flash memory can be rewritten as many as 100 times.
• The internal flash memory has a virtual flash emulation function, allowing the internal RAM to be
superficially mapped into part of the internal flash memory. When combined with the internal Real-
Time Debugger (RTD) and the M32R family's common debug interface (Scalable Debug Interface or
SDI), this function makes the ROM table data tuning easy.
• The internal RAM can be accessed for reading or rewriting data from an external device indepen-
dently of the M32R-FPU by using the Real-Time Debugger. The external device is communicated
using the Real-Time Debugger's exclusive clock-synchronized serial I/O.
1.1 Outline of the 32180 Group
32180 Group User's Manual (Rev.1.0)
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OVERVIEW