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Zilog Developer Studio II – Z8 Encore!

User Manual

top-level routines to parse a format string are not linked into the project, and only those

lower level routines that are actually used are linked in, rather than every routine that

could be used by a call to

printf. The code size of each routine that calls printf() or

sprintf() is slightly larger than if the Generate Printfs Inline checkbox is deselected,

but this is more than offset by the significant reduction in the size of library functions that

are linked to your application.

To reduce overall code size by selecting this checkbox, the following conditions are neces-

sary:

•

All calls to printf() and sprintf() must use string literals, rather than char*

variables, as parameters. For example, the following code allows the compiler to

reduce the code size:

sprintf ("Timer will be reset in %d seconds", reset_time);

But code such as the following results in larger code:

char * timerWarningMessage;

...

sprintf (timerWarningMessage, reset_time);

•

The vprintf() and vsprintf() functions cannot be used, even if the format string

is a string literal.

If the

Generate Printfs Inline checkbox is selected and these conditions are not met, the

compiler warns you that the code size cannot be reduced. In this case, the compiler gener-

ates correct code, and the execution is significantly faster than with normal

printf calls.

However, there is a net increase in code size because the generated inline calls to lower

level functions require more space with no compensating savings from removing the top-

level functions.

In addition, an application that makes over 100 separate calls of

printf or sprintf

might result in larger code size with the

Generate Printfs Inline checkbox selected

because of the cumulative effect of all of the inline calls. The compiler cannot warn about

this situation. If in doubt, simply compile the application both ways and compare the

resulting code sizes.

The

Generate Printfs Inline checkbox is selected by default.

Bit Field Packing

This drop-down list box can be set to

Backward Compatible, Most Compact, or Normal.

The

Most Compact setting, which is the default for new projects, packs the bit-fields as

tightly as possible. This packing saves data space in your application. The

Normal setting

preserves the declared type of all of the individual bit-fields. That is, in an example such

as:

typedef struct {

char bf1:6;

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