This paper presents a software-testing concept used for MICRONAS Intermetall MAS DSP C compiler MAS/C-Compiler. The concept is based on a specially developed software testing tool, which asserts whether the application generated by MAS/C-Compiler is valid or not. If not, it helps compiler designers to localize the bug, and to eliminate it. Compiler testing is viewed as continual process. For each new compiler test case the following two steps are conducted. (i) Reference error-free source code is designed using commercially available high quality C++ reference compilers. (ii) A specially developed bit-exact testing tool is used to compare outputs of application produced by reference compiler and application produced by MAS/C-Compiler. Based on this comparison, bug localization and elimination is possible.