Keil CA ARM Compiler

Preprocessor Symbols

Define: Sets preprocessor symbols which may be checked with #if, #ifdef and #ifndef. The defined names are copied exactly as they are entered (case-sensitive). Each name may get optionally a value. Define: Check, NoExtRam, X1=1+5 is identical to the following C preprocessor #define statements:
#define Check
#define NoExtRam
#define X1 1+5
Undefine: Clears previous Define assignments that are entered in the options dialog of a higher Target or Group level.

Level: Set the optimization level the Compiler uses when generating object code.
Emphasis: Specify whether the Compiler should optimize for code size or execution speed.
Alias Checking on Pointer Accesses: Select this check box to force the compiler to reload registers holding variables that have aliases (usually through pointers). When this check box is clear, the compiler reuses register contents even though a pointer or a other alias may have changed the variable.

Use Thumb Mode: Generate Thumb instructions for the C code in this module.
Warnings: Lets you suppress compiler warnings.
Treat plain 'char' as 'unsigned char': Instructs the Compiler to treat all variables declared with plain char as unsigned char variables.
Include Paths: Allows you to supply one or more (separated by semi-colon) paths to search for header files. For #include "filename.h" the Compiler searches first the current folder and then folder of the source file. When this fails or when #include <filename.h> is used, the paths specified in the include paths box are searched. When this still fails, the paths specified in for the INC folder under Project — Components, Environment, Books ... are used.
Misc Controls: Specify any directive for which there is no individual dialog control.
Compiler Control String: Displays the current directives at the Compiler command line.