Renesas V850 Series Technical Information PDF herunterladen (Seite 9)

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COMPILERS

The following compilers are supported in the V850 Series.

CA850: C compiler package for V850 Series

Features

◆ Complies with ANSI-C standard for C language programming

◆ Includes powerful optimization functions

◆ Provides functions optimized for embedded systems

◆ Provides multiple utilities

Powerful Optimization Functions

The CA850 comes with "powerful optimization functions" that make the most of the device's performance fea-

tures. Users can select among six optimization levels, and can even set optimization levels for individual sources.

Functions Optimized for Embedded Systems

The CA850 provides functions optimized for development of the embedded systems.

O Functions related to size reduction of ROM/RAM used and acceleration of execution speed

◆ Selection of register mode (software register bank function)

➝ Setting a limit on the number of registers that can be used by the compiler (either 22 or 26 registers) reduces the

interrupt overhead (saving to and restoring from registers).

◆ Run-time library is used for processing of function prologues and epilogues

➝ Code size is reduced by library functions that can be called both when saving to registers and when restoring from

registers (slightly accelerates execution speed).

◆ Structure/union packing function

➝ This packing function fills holes between members of structures or unions due to alignment, which reduces code

size (slightly accelerates execution speed).

◆ Register allocation function for external variables

➝ When in 22 or 26 register mode, the user can freely allocate external variables to any usable register and can

change the memory access to the register access. This can shrink the code size while accelerating execution

speed.

More advanced optimization

(size priority)

More advanced optimization

(execution speed priority)

More powerful

optimization

Less powerful

optimization

Advanced optimization

Standard optimization

Default optimization

Optimization for ease of debugging

Trade-off among ease of

debugging, code size,

and execution speed

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Renesas V850 Series Technical Information Seite 9