Chapter 7 DSP的C语言编程ppt课件.ppt

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1、第七章DSP的C语言编程SoftwaredevelopmentflowusingC/C++TheshadedportionofthefigurehighlightsthemostcommonpathofsoftwaredevelopmentforC/C++languageprograms.8/21/20212C/C++ComplierOverviewANSIStandardTheC54xC/C++compilerisafull-featuredoptimizingcompilerthattranslatesstandardANSIC/C++pro

2、gramsintoC54xassemblylanguagesource.Thefollowingsubsectionsdescribethekeyfeaturesofthecompiler.ANSI-standardCThecompilerfullyconformstoANSICStandard.C++ThecompileralsosupportsC++.ANSI-standardruntimesupportAllruntimelibraryfunctionsconformtoANSI-standard.8/21/20213OutputFiles

3、AssemblysourceoutputGeneratesassemblylanguagesourcefilesthatyoucaninspecteasily,enablingyoutoseethecodegeneratedfromtheC/C++sourcefiles.COFFobjectfilesCommonObjectFileFormat,allowstheusertodefinethesystem’smemorymapatlinktime.CodetoinitializedataintoROMEnablestheusertolinkall

4、codeandinitializationdataintoROM,allowingC/C++codetorunfromreset.8/21/20214CompileroperationIntegratedPreprocessorTheC/C++preprocessorisintegratedwiththeparser,allowingfastercompilation.Standalonepreprocessororpreprocessorlistingisalsoavailable.OptimizationUsesasophisticatedo

5、ptimizationpassthatemploysseveraladvancedtechniquesforgeneratingefficient,compactcodefromC/C++source.GeneralOptimizationforanyC/C++codeandC54xspecificoptimizationsforC54xarchitecture.8/21/20215CCS的C语言简介由DSP厂商及第三方为DSP提供C编译器；使得采用高级语言开发DSP软件成为可能；TI公司的CCS又提供了优化的C编译器；优化后的C编译器得到的代码

6、效率只比汇编语言低10%~20%；DSP的C编译器还在不断优化；DSP的C编译器符合ANSIC标准；ANSIC标准会受处理器、运行环境或主机环境的影响。8/21/20216DSP的C语言特性标识符和常数(IdentifierandConstant)标识符大小写敏感，且前100个字符有效；主机和目标字符集为ASCII吗，不存在多字节字符多字符常数按最后一个字符编码。数据类型(DataTypes)与普通C语言类似，不同的是C54x的一个字节为16bits，而并非8bits；表数范围也相应有所变化；size_t的类型为unsignedint，也就是si

7、zeof运算符的结果；prtdiff_t的类型为int—指针相减的结果。8/21/202178/21/20218DataConversion()Float-to-intconversionstruncatetoward0.Pointersandintegerscanbefreelyconverted,aslongastheresulttypeislargeenoughtoholdtheoriginalvalue.ExpressionsWhentwosignedintegersaredividedandeitherisnegative,thequo

8、tientisnegative,andthesignoftheremainderisthesameasthesignofthenumer