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µVision3 User's Guide

µVision3 Overview User Interface Creating Applications Utilities Debugging Debug Commands Debug Functions Simulation Flash Programming Dialogs File Device Database License Management Single-User License Floating-User License Floating License Administrator Edit Find in Files Configuration Editor Colors & Fonts User Keywords Shortcut Keys Templates View Symbol Window Project Components, Enviornment, and Books Project Components Folders/Extensions Books Multi-Project Select Device Options Device Properties Target Target (Keil ARM) Target (Keil C51) Target (Keil C166) Target (Keil C251) Target (GNU ARM) Target (RealView ARM) Output Output (Keil) Output (GNU ARM) Output (RealView ARM) Listing Listing (Keil) Listing (GNU ARM) Listing (RealView ARM) User Keil EC++ Compiler Compiler Keil CA ARM Compiler Keil Cx51 Compiler Keil C166 Compiler Keil C251 Compiler GNU ARM C Compiler RealView ARM C Compiler Assembler Keil AA ARM Assembler Keil Ax51 Assembler Keil A166 Assembler Keil A251 Assembler GNU ARM Assembler RealView ARM Assembler Linker Keil LA Locate Keil LA Misc Keil BL51 Locate Keil BL51 Misc Keil Lx51 Locate Keil Lx51 Misc Keil L166 Locate Keil L166 Misc GNU ARM Linker RealView ARM Linker Debug Utilities Batch Build Debug Breakpoints Debug Settings Logic Analyzer Memory Map Performance Analyzer Function Editor Tools Setup PC-Lint Customize Tools Menu SVCS Configure Version Control Example Programs Command Line Appendix

Keil Cx51 Compiler

Preprocessor Symbols

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.

Code Optimization

Set the optimization level the Compiler uses when generating object code.
Specify whether the Compiler should optimize for code size or execution speed.
Global Register Coloring
Enable application wide register optimization. When set the c51 compiler knows the registers used by external functions and µVision performs automatically iterative re-translations of C source files to improve the register allocation.
Linker Code Packing (max. AJMP / ACALL)
Instructs the compiler to include information in the object file for the linker-level program optimizations. When enabled, the LX51 linker/locater performs this optimizations.
Don't use absolute register accesses
Disables absolute register addressing for registers R0 through R7 which allows function calls from different register banks. The code will be slightly longer, since C compiler cannot use ARx symbols, i.e. in PUSH or POP instructions and needs to insert replacement code. However the code will be independent of the selected register bank.

Other Controls

Lets you to suppress compiler warnings.
Bits to round for float compare
Determines the number of bits rounded before a floating-point compare is executed. The default value of 3 specifies that the three least significant bits of a float value are rounded before the floating-point compare is executed.
Interrupt vectors at address
Instructs the C Compiler to generate interrupt vectors for interrupt functions and specifies the base address for the interrupt vector table.
Keep Variables in Order
Order all variables in memory according to their order of definition in the C source file.
Enable ANSI integer promotion rules
Expressions are promoted from smaller types to integer expressions before the operation is performed. Integer promotion is normally enabled to provide the greatest compatibility between Cx51 and other ANSI compilers
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
Display the current directives at the Compiler command line.
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