【研发日记】Matlab/Simulink自动生成代码(二)——五种选择结构实现方法

文章目录

前言

Simulink实现选择结构

自动生成C代码

变式一

变式二

变式三

变式四

总结

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前言

        见《深入拆解Simulink自动生成代码（一）——数据流处理》

Simulink实现选择结构

         用Simulink实现选择结构的一个最简单编程举例如下：

自动生成C代码

         上述选择结构的Simulink自动生成的对应C代码如下：

  /* Switch: '/Switch' incorporates:   *  UnitDelay: '/Output'   */  if (CodeGenerate_DW.Output_DSTATE > 0) {    /* Outport: '/y1' incorporates:     *  Constant: '/Constant'     */    CodeGenerate_Y.y1 = 5.0;  } else {    /* Outport: '/y1' incorporates:     *  Constant: '/Constant2'     */    CodeGenerate_Y.y1 = 10.0;  }  /* End of Switch: '/Switch' */  /* Switch: '/FixPt Switch' incorporates:   *  Constant: '/FixPt Constant'   *  Constant: '/Constant'   *  Sum: '/FixPt Sum1'   *  UnitDelay: '/Output'   */  if ((uint8_T)(CodeGenerate_DW.Output_DSTATE + 1U) > 7) {    CodeGenerate_DW.Output_DSTATE = 0U;  } else {    CodeGenerate_DW.Output_DSTATE++;  }  /* End of Switch: '/FixPt Switch' */

变式一

         基于上述举例，增加选择结构的选项，生成的对应代码如下所示：

  /* SwitchCase: '/Switch Case' incorporates:   *  UnitDelay: '/Output'   */  switch (CodeGenerate_DW.Output_DSTATE) {   case 1:    /* Outputs for IfAction SubSystem: '/Switch Case Action Subsystem' incorporates:     *  ActionPort: '/Action Port'     */    /* Outport: '/y1' incorporates:     *  Constant: '/Constant1'     *  Inport: '/In1'     */    CodeGenerate_Y.y1 = 5.0;    /* End of Outputs for SubSystem: '/Switch Case Action Subsystem' */    break;   case 2:    /* Outputs for IfAction SubSystem: '/Switch Case Action Subsystem1' incorporates:     *  ActionPort: '/Action Port'     */    /* Outport: '/y1' incorporates:     *  Constant: '/Constant3'     *  Inport: '/In1'     */    CodeGenerate_Y.y1 = 10.0;    /* End of Outputs for SubSystem: '/Switch Case Action Subsystem1' */    break;   case 3:    /* Outputs for IfAction SubSystem: '/Switch Case Action Subsystem2' incorporates:     *  ActionPort: '/Action Port'     */    /* Outport: '/y1' incorporates:     *  Constant: '/Constant4'     *  Inport: '/In1'     */    CodeGenerate_Y.y1 = 15.0;    /* End of Outputs for SubSystem: '/Switch Case Action Subsystem2' */    break;   default:    /* Outputs for IfAction SubSystem: '/Switch Case Action Subsystem3' incorporates:     *  ActionPort: '/Action Port'     */    /* Outport: '/y1' incorporates:     *  Constant: '/Constant5'     *  Inport: '/In1'     */    CodeGenerate_Y.y1 = 0.0;    /* End of Outputs for SubSystem: '/Switch Case Action Subsystem3' */    break;  }  /* End of SwitchCase: '/Switch Case' */  /* Switch: '/FixPt Switch' incorporates:   *  Constant: '/FixPt Constant'   *  Constant: '/Constant'   *  Sum: '/FixPt Sum1'   *  UnitDelay: '/Output'   */  if ((uint8_T)(CodeGenerate_DW.Output_DSTATE + 1U) > 7) {    CodeGenerate_DW.Output_DSTATE = 0U;  } else {    CodeGenerate_DW.Output_DSTATE++;  }  /* End of Switch: '/FixPt Switch' */

变式二

         基于上述举例，升级选择结构的判断条件，生成的对应代码如下所示：

  real_T tmp;  /* Math: '/Mod' incorporates:   *  Constant: '/Constant6'   *  DataTypeConversion: '/Data Type Conversion'   *  Math: '/Mod1'   *  Math: '/Mod2'   *  UnitDelay: '/Output'   */  tmp = rt_modd_snf((real_T)CodeGenerate_DW.Output_DSTATE, 3.0);  /* Outputs for Enabled SubSystem: '/Subsystem' incorporates:   *  EnablePort: '/Enable'   */  /* RelationalOperator: '/Compare' incorporates:   *  Constant: '/Constant'   *  Math: '/Mod'   */  if (tmp == 0.0) {    /* Merge: '/Merge1' incorporates:     *  Constant: '/Constant7'     *  Inport: '/In1'     */    CodeGenerate_B.Merge1 = 5.0;  }  /* End of RelationalOperator: '/Compare' */  /* End of Outputs for SubSystem: '/Subsystem' */  /* Outputs for Enabled SubSystem: '/Subsystem1' incorporates:   *  EnablePort: '/Enable'   */  /* RelationalOperator: '/Compare' incorporates:   *  Constant: '/Constant'   */  if (tmp == 1.0) {    /* Merge: '/Merge1' incorporates:     *  Constant: '/Constant9'     *  Inport: '/In1'     */    CodeGenerate_B.Merge1 = 10.0;  }  /* End of RelationalOperator: '/Compare' */  /* End of Outputs for SubSystem: '/Subsystem1' */  /* Outputs for Enabled SubSystem: '/Subsystem2' incorporates:   *  EnablePort: '/Enable'   */  /* RelationalOperator: '/Compare' incorporates:   *  Constant: '/Constant'   */  if (tmp == 2.0) {    /* Merge: '/Merge1' incorporates:     *  Constant: '/Constant11'     *  Inport: '/In1'     */    CodeGenerate_B.Merge1 = 15.0;  }  /* End of RelationalOperator: '/Compare' */  /* End of Outputs for SubSystem: '/Subsystem2' */  /* Switch: '/FixPt Switch' incorporates:   *  Constant: '/FixPt Constant'   *  Constant: '/Constant'   *  Sum: '/FixPt Sum1'   *  UnitDelay: '/Output'   */  if ((uint8_T)(CodeGenerate_DW.Output_DSTATE + 1U) > 7) {    CodeGenerate_DW.Output_DSTATE = 0U;  } else {    CodeGenerate_DW.Output_DSTATE++;  }  /* End of Switch: '/FixPt Switch' */  /* Outport: '/y1' incorporates:   *  MATLAB Function: '/MATLAB Function2'   */  CodeGenerate_Y.y1 = CodeGenerate_B.Merge1;

变式三

         基于上述举例，用MATLAB Function来实现，生成的对应代码如下所示：

#include "untitled.h"#include "untitled_private.h"/* Block states (default storage) */DW_untitled_T untitled_DW;/* External outputs (root outports fed by signals with default storage) */ExtY_untitled_T untitled_Y;/* Real-time model */static RT_MODEL_untitled_T untitled_M_;RT_MODEL_untitled_T *const untitled_M = &untitled_M_;/* Model step function */void untitled_step(void){  uint8_T rtb_Output;  /* UnitDelay: '/Output' */  rtb_Output = untitled_DW.Output_DSTATE;  /* Switch: '/FixPt Switch' incorporates:   *  Constant: '/FixPt Constant'   *  Constant: '/Constant'   *  Sum: '/FixPt Sum1'   *  UnitDelay: '/Output'   */  if ((uint8_T)(untitled_DW.Output_DSTATE + 1U) > 7) {    untitled_DW.Output_DSTATE = 0U;  } else {    untitled_DW.Output_DSTATE++;  }  /* End of Switch: '/FixPt Switch' */  /* MATLAB Function: '/MATLAB Function' */  switch (rtb_Output) {   case 1:    /* Outport: '/y' */    untitled_Y.y = 5.0;    break;   case 2:    /* Outport: '/y' */    untitled_Y.y = 10.0;    break;   case 3:    /* Outport: '/y' */    untitled_Y.y = 15.0;    break;   default:    /* Outport: '/y' */    untitled_Y.y = 0.0;    break;  }  /* End of MATLAB Function: '/MATLAB Function' */}

变式四

        基于上述举例，用Stateflow配合Simulink Function来实现选择结构，参见《【研发日记】嵌入式处理器技能解锁(一)——多任务异步执行调度的三种方法》，示例如下：

总结

         以上就是本人拆解Simulink模块自动生成代码时，讲解的第二部分。主要针对Simulink的选择结构，展示了这类模块的使用方法，并对比了相应的C代码。

         后续还会更新Simulink其他的几种模块，欢迎评论区留言、点赞、收藏和关注，这些鼓励和支持都将成为笔者持续分享的动力。

         另外，上述例程使用的Demo工程可以到笔者的主页查找和下载。

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