AN3350 datasheet(174/185 Pages) STMICROELECTRONICS

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Pragmas for optimization

AN3350

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Doc ID 018512 Rev 2

22.13

optimize_for_size

Controls optimization to reduce the size of object code.

#pragma optimize_for_size on | off | reset

Remarks

This setting lets you choose what the compiler does when it must decide between creating

small code or fast code. If you enable this pragma, the compiler creates smaller object code

at the expense of speed. It also ignores the inline directive and generates function calls to

call any function declared inline. If you disable this pragma, the compiler creates faster

object code at the expense of size.

The pragma corresponds to the optimize for size setting on the global optimizations panel.

22.14

optimizewithasm

Controls optimization of assembly language.

Syntax

#pragma optimizewithasm on | off | reset

Remarks

If you enable this pragma, the compiler also optimizes assembly language statements in

C/C++ source code.

This pragma does not correspond to any panel setting. By default, this pragma is disabled.

22.15

pack

Stores data to reduce data size instead of improving execution performance.

Syntax

#pragma pack()

#pragma pack(0 | n | push | pop)

One of these integer values: 1, 2, 4, 8, or 16.

Remarks

Use this pragma to align data to use less storage even if the alignment might affect program

performance or does not conform to the target platform’s application binary interface (ABI).

If this pragma’s argument is a power of 2 from 1 to 16, the compiler will store subsequent

data structures to this byte alignment.

The push argument saves this pragma’s setting on a stack at compile time. The pop

argument restores the previously saved setting and removes it from the stack. Using this

pragma with no argument or with 0 as an argument specifies that the compiler will use ABI-

conformant alignment.

AN3350 Datasheet(PDF) 174 Page - STMicroelectronics