Simulink代码生成（六）——ert.tlc下默认配置生成代码的解读

一、代码生成的结构：

模块是构成Simulink模型的最小单元，因此可明确将一个模块分为7个部分，出去接地的rtGround之外，其余6个部分都明确了生成代码时所使用的变量生成格式，都对构成模块的各个对象的生成变量进行了结构体的约束，并且对结构体的变量名前缀进行了规定。

Model表示当前模型名，生成的代码遵循以下规则。

二、model.rtw文件解读

模块是构成Simulink模型的最小单元，因此可明确将一个模块分为7个部分，出去接地的rtGround之外，其余6个部分都明确了生成代码时所使用的变量生成格式，都对构成模块的各个对象的生成变量进行了结构体的约束，并且对结构体的变量名前缀进行了规定。

生成代码如下，rtwtypes.h是ert.tlc生成代码所要用到的数据类型的定义，不需要修改和考虑。
从untitled.h中可以看到，输入和输出的定义分别放到了不同的结构体中，两个delay模块放到了DW的结构体（也就是工作向量中），模块用到的数据都放到了P相关的结构体中。
注意两个delay参数，delayonestep模块还生成了一个变量DelayOneStep_DelayLength，其数据类型为uint32_T，通过untitled.c可以看到这个值为1，表示的是Z^-1的1.

/*
 * File: untitled.h
 *
 * Code generated for Simulink model 'untitled'.
 *
 * Model version                  : 1.9
 * Simulink Coder version         : 9.0 (R2018b) 24-May-2018
 * C/C++ source code generated on : Tue Oct 18 22:11:38 2022
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Intel->x86-64 (Windows64)
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#ifndef RTW_HEADER_untitled_h_
#define RTW_HEADER_untitled_h_
#include "rtwtypes.h"
#include <stddef.h>
#include <string.h>
#ifndef untitled_COMMON_INCLUDES_
# define untitled_COMMON_INCLUDES_
#include "rtwtypes.h"
#endif                                 /* untitled_COMMON_INCLUDES_ */

/* Macros for accessing real-time model data structure */
#ifndef rtmGetErrorStatus
# define rtmGetErrorStatus(rtm)        ((rtm)->errorStatus)
#endif

#ifndef rtmSetErrorStatus
# define rtmSetErrorStatus(rtm, val)   ((rtm)->errorStatus = (val))
#endif

/* Forward declaration for rtModel */
typedef struct tag_RTM_untitled_T RT_MODEL_untitled_T;

/* Block states (default storage) for system '<Root>' */
typedef struct {
  real_T UnitDelay_DSTATE;             /* '<Root>/Unit Delay' */
  real_T DelayOneStep_DSTATE;          /* '<Root>/Delay One Step' */
} DW_untitled_T;

/* External inputs (root inport signals with default storage) */
typedef struct {
  real_T In1;                          /* '<Root>/In1' */
} ExtU_untitled_T;

/* External outputs (root outports fed by signals with default storage) */
typedef struct {
  real_T Out1;                         /* '<Root>/Out1' */
} ExtY_untitled_T;

/* Parameters (default storage) */
struct P_untitled_T_ {
  real_T Gain1_Gain;                   /* Expression: 2
                                        * Referenced by: '<Root>/Gain1'
                                        */
  real_T Gain_Gain;                    /* Expression: 1.5
                                        * Referenced by: '<Root>/Gain'
                                        */
  real_T UnitDelay_InitialCondition;   /* Expression: 0
                                        * Referenced by: '<Root>/Unit Delay'
                                        */
  real_T DelayOneStep_InitialCondition;/* Expression: 0.0
                                        * Referenced by: '<Root>/Delay One Step'
                                        */
  real_T Switch_Threshold;             /* Expression: 0
                                        * Referenced by: '<Root>/Switch'
                                        */
  uint32_T DelayOneStep_DelayLength;   /* Computed Parameter: DelayOneStep_DelayLength
                                        * Referenced by: '<Root>/Delay One Step'
                                        */
};

/* Parameters (default storage) */
typedef struct P_untitled_T_ P_untitled_T;

/* Real-time Model Data Structure */
struct tag_RTM_untitled_T {
  const char_T * volatile errorStatus;
};

/* Block parameters (default storage) */
extern P_untitled_T untitled_P;

/* Block states (default storage) */
extern DW_untitled_T untitled_DW;

/* External inputs (root inport signals with default storage) */
extern ExtU_untitled_T untitled_U;

/* External outputs (root outports fed by signals with default storage) */
extern ExtY_untitled_T untitled_Y;

/* Model entry point functions */
extern void untitled_initialize(void);
extern void untitled_step(void);
extern void untitled_terminate(void);

/* Real-time Model object */
extern RT_MODEL_untitled_T *const untitled_M;

/*-
 * The generated code includes comments that allow you to trace directly
 * back to the appropriate location in the model.  The basic format
 * is <system>/block_name, where system is the system number (uniquely
 * assigned by Simulink) and block_name is the name of the block.
 *
 * Use the MATLAB hilite_system command to trace the generated code back
 * to the model.  For example,
 *
 * hilite_system('<S3>')    - opens system 3
 * hilite_system('<S3>/Kp') - opens and selects block Kp which resides in S3
 *
 * Here is the system hierarchy for this model
 *
 * '<Root>' : 'untitled'
 */
#endif                                 /* RTW_HEADER_untitled_h_ */

/*
 * File trailer for generated code.
 *
 * [EOF]
 */

untitled.c先对untitled.h中声明的结构体进行定义，以及进行初始化。参数的初始化是在结构体定义的时候直接赋值进行初始化的，而其他的结构体类型都是在untitled_initialize函数中进行初始化的。初始化函数只执行一次。
untitled_step函数是模型转化成的算法代码，一般会放到while中执行。

/*
 * File: untitled.c
 *
 * Code generated for Simulink model 'untitled'.
 *
 * Model version                  : 1.9
 * Simulink Coder version         : 9.0 (R2018b) 24-May-2018
 * C/C++ source code generated on : Tue Oct 18 22:11:38 2022
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Intel->x86-64 (Windows64)
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#include "untitled.h"

/* Block parameters (default storage) */
P_untitled_T untitled_P = {
  /* Expression: 2
   * Referenced by: '<Root>/Gain1'
   */
  2.0,

  /* Expression: 1.5
   * Referenced by: '<Root>/Gain'
   */
  1.5,

  /* Expression: 0
   * Referenced by: '<Root>/Unit Delay'
   */
  0.0,

  /* Expression: 0.0
   * Referenced by: '<Root>/Delay One Step'
   */
  0.0,

  /* Expression: 0
   * Referenced by: '<Root>/Switch'
   */
  0.0,

  /* Computed Parameter: DelayOneStep_DelayLength
   * Referenced by: '<Root>/Delay One Step'
   */
  1U
};

/* Block states (default storage) */
DW_untitled_T untitled_DW;

/* External inputs (root inport signals with default storage) */
ExtU_untitled_T untitled_U;

/* External outputs (root outports fed by signals with default storage) */
ExtY_untitled_T untitled_Y;

/* Real-time model */
RT_MODEL_untitled_T untitled_M_;
RT_MODEL_untitled_T *const untitled_M = &untitled_M_;

/* Model step function */
void untitled_step(void)
{
  /* Outport: '<Root>/Out1' incorporates:
   *  UnitDelay: '<Root>/Unit Delay'
   */
  untitled_Y.Out1 = untitled_DW.UnitDelay_DSTATE;

  /* Delay: '<Root>/Delay One Step' incorporates:
   *  UnitDelay: '<Root>/Unit Delay'
   */
  untitled_DW.UnitDelay_DSTATE = untitled_DW.DelayOneStep_DSTATE;

  /* Switch: '<Root>/Switch' incorporates:
   *  Delay: '<Root>/Delay One Step'
   *  Gain: '<Root>/Gain'
   *  Gain: '<Root>/Gain1'
   *  Inport: '<Root>/In1'
   */
  if (untitled_U.In1 > untitled_P.Switch_Threshold) {
    untitled_DW.DelayOneStep_DSTATE = untitled_P.Gain_Gain * untitled_U.In1;
  } else {
    untitled_DW.DelayOneStep_DSTATE = untitled_P.Gain1_Gain * untitled_U.In1;
  }

  /* End of Switch: '<Root>/Switch' */
}

/* Model initialize function */
void untitled_initialize(void)
{
  /* Registration code */

  /* initialize error status */
  rtmSetErrorStatus(untitled_M, (NULL));

  /* states (dwork) */
  (void) memset((void *)&untitled_DW, 0,
                sizeof(DW_untitled_T));

  /* external inputs */
  untitled_U.In1 = 0.0;

  /* external outputs */
  untitled_Y.Out1 = 0.0;

  /* InitializeConditions for UnitDelay: '<Root>/Unit Delay' */
  untitled_DW.UnitDelay_DSTATE = untitled_P.UnitDelay_InitialCondition;

  /* InitializeConditions for Delay: '<Root>/Delay One Step' */
  untitled_DW.DelayOneStep_DSTATE = untitled_P.DelayOneStep_InitialCondition;
}

/* Model terminate function */
void untitled_terminate(void)
{
  /* (no terminate code required) */
}

/*
 * File trailer for generated code.
 *
 * [EOF]
 */