蓝星のXSK'S BLOG

from: xbox-scene
这篇文章是XBOX上最新的SFC模拟器 Zsnexbox 的移植作者 nes6502 写的，简单的介绍了如何移植一些程序到XBOX
The reason I wrote this guide was to explain the process of porting a game or an emulator to the Xbox. You don’t have to be a coding master. All you need is the tools to build an Xbox application, basic knowledge of C (and or C++), and some determination. I am not the authority on the subject, but I have ported an emulator to the Xbox, and I am writing from this experience. This is a VERY high level view. But the framework is here.

Why am I writing this and posting it in the emulators forum? I realize that many emulator users read this forum and might want their favorite application/game/emulator ported to the Xbox. In reality, the only way it may ever get ported is if they do it themselves. I have wanted ZSNES on the Xbox (native port) since I started using the Xbox, and I realised that the only way it was going to happen was if I did it myself. So I did. I had never ported anything to the Xbox (or any console) before and I am not an expert coder. With determination I was able to do it, and i think it turned out well. So if you want your favorite app/emulator/game on the Xbox, instead of waiting for a day that may never come, people might want to try and do it themselves. This is a basic guide for those people that don't know where to begin.

Tools:

1) XDK
2) Visual Studio 2003. NET
3) You do not need a debug XBOX (even though it is helpful). Without one, you will be burning CD’s every time you want to test a change.

Step 1) Decide what you want to port. For this example I will talk about ZSNES. ZSNES is written in C and Assembly. I’m pretty familiar with C and not very familiar with Assembly.

Step 2) Download the source code. It’s easiest if you can compile it on Windows first. After following the instructions, I was able to compile the windows version of ZSNES.

Step 3) Create a new Xbox application workspace in VS 2003. Add all the C/C++ files to the project. If there are assembly files (like in ZSNES), just add the “obj” files for the ASM ones generated from Step 2 to the project.

Step 4) Compile the Xbox project. This is where the fun starts. There will be lots of compile errors because the PC version is likely using code, functions, libraries that are not supported on the Xbox. For example, ZSNES uses DirectDraw code to draw the screen. There is no DirectDraw support on the Xbox, so I had to learn how to do the same thing with Direct3D. Basically: how to set the color of each pixel on the screen. Once I replaced all the DirectDraw code, that entire group of errors went away.

Another example is the input. ZSNES assumes there is a mouse used. I commented out all the code that used a mouse because there isn’t one on the Xbox. Another example is the keyboard. Since there is no Xbox keyboard, I replaced all the keyboard code with Xbox controller code. ZSNES still thinks there is a keyboard attached and checks to see if any buttons are pressed. I just monitor buttons on the Xbox controller, and when one is pressed, I tell ZSNES that one of the keyboard keys was pressed.

Step 5) Compile again. Now continue replacing code that gives errors with code that doesn’t.

Step 6) Repeat Step 5 until all errors are gone. Once all the errors are fixed, VS will generate an “xbe” file that can be run on the Xbox.

A great starting point is the Genadrive source code. It is easy to read and easy to compile. Try compiling it and running it on the Xbox. Then study what it is doing to draw pixels on the screen, read the controller, read files in a directory for the ROM browser, etc.. In fact I used this as my base for ZsnexBox and basically built around it, added to it, etc...This is the only thing I’ve ported to the Xbox and I am not a coding expert. You don’t have to be. If you have a basic understanding of C, the tools needed to compile the application, and the willingness to learn things you need (like basic Direct3D), then there is nothing stopping you from porting anything you want.

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这里还有一篇讲如何移植sdl程序的（使用lantus大大移植的SDLx)
Wondering if someone would be willing to write a "how I ported this game to the xbox" tutorial. I see some very simple demos and apps that look like they should be simple to port over, such as:

http://www.libsdl.org/projects/fire

I think this would help spark some more interest in porting already available SDL based games and apps to the XBOX.

-hurtz






qucik tutorial for converting the 'fire' app you suggested:

(this was far easier than i expected )

For fire, create a xbox application, set it to be an empty project (no pch headers). Add the fire.c file to it. Add the path of your SDLx includes to the path for library header in the project properties. This should compile now, but not link. To make it link add the libsdlx.lib (or whatever your copy is called) to the list of libs the linker will use (properties again). Build your project and you should have a sucessfully ported 'fire' sample app.

More Info:

First you need to get SDLx installed and compiled (or use the precompiled libs).

Then you need to determine what libraries the app you are porting uses. In the case of fire, this is none. For scummvm, this would be libmad, libmpeg2, and a few others.

For the libraries, create a visual studio project, xbox application, and set type to library without pch headers. Then add the source files to the project from the libraries, set the preprocessor defines from the original library in the new project, and compile. Hopefully this will create you lib for you.

For the main application, create a new project for an xbox game. make it an empty project. Add to this project all your files for the thing youre porting. Make sure you set and defines the project needs up. Scummvm needed several such as USE_MPEG2, USE_VORBIS, and USE_MAD. Put these defines in the properties of the project, c/c++, preprocessor, preprocessor definitions.

Your next step is getting the code to fully compile. I found on of the easiest ways to do this is comment out code chunk and functions that wont compile, marking them or writing them down so you can find em later.

Once compliled, you can try and run your app. Depending on how much you commented out, is how well it runs.

One thing that very usefull is the XKUtils package. Not sure where to get this, i blagged a copy within the source of guybrush port of scummvm.

If it need file or disk access, you need to mount your hard drives somewhere within your code. Generally this is done using the following code

XKUtils::MountAllDisks();

after includeing the xkutils.h header file.

File access has to be done using full paths. An Xbox cant use relative paths (WHY!!!!! its a pain).

If you want to pass command line arguments to your project:

char *x_argv[100];
int x_argc = 1;
DWORD dwLaunchType;
LAUNCH_DATA LaunchData;
XGetLaunchInfo(&dwLaunchType, &LaunchData);

if (dwLaunchType == LDT_FROM_DEBUGGER_CMDLINE)
{
x_argv[x_argc] = strtok(((PLD_FROM_DEBUGGER_CMDLINE)&LaunchData)->szCmdLine, " ");
while (x_argv[x_argc] != NULL) {
x_argc++;
x_argv[x_argc] = strtok(NULL, " ");
}
}

sould put command line args in x_argv[].

Theres no need to worry about full screen mode or anything similar, once sdlx is intialised, its always fullscreen and you screen res chosen is scaled.

Also use the following functions to control how much overscan is used etc.

SDL_XBOX_SetScreenPosition(x,y);
SDL_XBOX_SetScreenStretch(xs,ys);


Hope some of this helps.

Clarky

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地址是 http://gezhi.org/user/hui
如站上描述所讲的
格志从一个群组 blog 开始，现在希望成为一个面向科研人员，学生，和科学作家与记者的社区网站。我们在这里 blog on 科学 blog 圈；分享科技知识，新闻，努力做点高级科普；作为学术交流平台，网络上的 common room。我们欢迎任何对科学感兴趣，从事科学研究或者科技新闻报道的人参与我们，让这个地方变得更有用有趣。

这是一个团体BLOG,很有意思~XD

而HUI写的这篇关于PSP HAKING的文章非常的全...也很有水准
你可以参见这里
http://gezhi.org/node/211

circular doubly-linked lists/queues的实现list结构的definition

typedef struct list_s *list;
struct list_s {
  list prev;
  list next;
  void *item;
};

创建一个空链表，返回一个指向list的指针，initialize list，分配一个header结点

/* Create an empty list, returning a pointer to the list */
list list_new(void)
{
  list l = zmalloc(sizeof(struct list_s)); //分配空间

  l->next = l->prev = l; 
  l->item = NULL;

  return l;
}

迭代删除这个链表..用2个指针P和Q

/* Delete a list, freeing its nodes */
void list_delete(list l)
{
  list p = l, q;

  do {
    q = p;
    p = p->next;
    free(q);
  } while (p != l);
}

用length遍历list记录表长
/* Return the length of a list */

size_t list_length(list l)
{
  list p;
  size_t length = 0;

  for (p = l->next; p != l; p = p->next)
    ++length;

  return length;
}

从表头插入一个数值为i的node

/* Add an item to the head of a list, returning the new list head */
list list_prepend(list l, void *i)
{
  list n = zmalloc(sizeof(struct list_s));

  n->next = l->next;
  n->prev = l;
  n->item = i;
  l->next = l->next->prev = n;

  return n;
}

从表尾插入i，把i的next指到header结点

/* Add an item to the tail of a list, returning the new list tail */
list list_append(list l, void *i)
{
  list n = zmalloc(sizeof(struct list_s));

  n->next = l;
  n->prev = l->prev;
  n->item = i;
  l->prev = l->prev->next = n;

  return n;
}

返回第一个item的值，list为空则返回NULL

/* Return the first item of a list, or NULL if the list is empty */
void *list_head(list l)
{
  list p = l->next;

  if (p == l)
    return NULL;

  return p->item;
}

移除第一个item，list为空则返回NULL

/* Remove the first item of a list, returning the item, or NULL if the
   list is empty */
void *list_behead(list l)
{
  void *i;
  list p = l->next;

  if (p == l)
    return NULL;
  i = p->item;
  l->next = l->next->next;
  l->next->prev = l;
  free(p);

  return i;
}

移除最后一个item

/* Remove the last item of a list, returning the item, or NULL if the
   list is empty */
void *list_betail(list l)
{
  void *i;
  list p = l->prev;

  if (p == l)
    return NULL;
  i = p->item;
  l->prev = l->prev->prev;
  l->prev->next = l;
  free(p);

  return i;
}

范围对应第N个元素的数值，越界操作则返回空

/* Return the nth item of l, or l->item (usually NULL) if that is out
   of range */
void *list_at(list l, size_t n)
{
  size_t i;
  list p;
        
  assert(l != NULL);

  for (p = list_first(l), i = 0; p != l && i < n; p = list_next(p), i++)
    ;
  
  return p->item;
}

通过cmp function对list进行排序，因为不能在list中直接进行排序，所以把每个元素迭代放入数组vec中进行
qsort(stdlib.c 快速排序)后再放回list

/* Sort list l with qsort using comparison function cmp */
void list_sort(list l, int (*cmp)(const void *p1, const void *p2))
{
  list p;
  void **vec;
  size_t i, len = list_length(l);

  assert(l != NULL && cmp != NULL); //assert传入数值不为空

  vec = (void **)zmalloc(sizeof(void *) * len);

  for (p = list_first(l), i = 0; i < len; p = list_next(p), ++i)
    vec[i] = (void *)p->item;

  qsort(vec, len, sizeof(void *), cmp);

  for (p = list_first(l), i = 0; i < len; p = list_next(p), ++i)
    p->item = vec[i];

  free(vec);
}

About qsort

七种qsort排序方法 

<本文中排序都是采用的从小到大排序> 

一、对int类型数组排序 

int num[100]; 

Sample: 

int cmp ( const void *a , const void *b ) 
{ 
return *(int *)a - *(int *)b; 
} 

qsort(num,100,sizeof(num[0]),cmp); 

二、对char类型数组排序（同int类型） 

char word[100]; 

Sample: 

int cmp( const void *a , const void *b ) 
{ 
return *(char *)a - *(int *)b; 
} 

qsort(word,100,sizeof(word[0]),cmp); 

三、对double类型数组排序（特别要注意） 

double in[100]; 

int cmp( const void *a , const void *b ) 
{ 
return *(double *)a > *(double *)b ? 1 : -1; 
} 

qsort(in,100,sizeof(in[0]),cmp)； 

四、对结构体一级排序 

struct In 
{ 
double data; 
int other; 
}s[100] 

//按照data的值从小到大将结构体排序,关于结构体内的排序关键数据data的类型可以很多种，参考上面的例子写 

int cmp( const void *a ,const void *b) 
{ 
return (*(In *)a)->data > (*(In *)b)->data ? 1 : -1; 
} 

qsort(s,100,sizeof(s[0]),cmp); 

五、对结构体二级排序 

struct In 
{ 
int x; 
int y; 
}s[100]; 

//按照x从小到大排序，当x相等时按照y从大到小排序 

int cmp( const void *a , const void *b ) 
{ 
struct In *c = (In *)a; 
struct In *d = (In *)b; 
if(c->x != d->x) return c->x - d->x; 
else return d->y - c->y; 
} 

qsort(s,100,sizeof(s[0]),cmp); 

六、对字符串进行排序 

struct In 
{ 
int data; 
char str[100]; 
}s[100]; 

//按照结构体中字符串str的字典顺序排序 

int cmp ( const void *a , const void *b ) 
{ 
return strcmp( (*(In *)a)->str , (*(In *)b)->str ); 
} 

qsort(s,100,sizeof(s[0]),cmp); 

七、计算几何中求凸包的cmp 

int cmp(const void *a,const void *b) //重点cmp函数，把除了1点外的所有点，旋转角度排序 
{ 
struct point *c=(point *)a; 
struct point *d=(point *)b; 
if( calc(*c,*d,p[1]) < 0) return 1; 
else if( !calc(*c,*d,p[1]) && dis(c->x,c->y,p[1].x,p[1].y) < dis(d->x,d->y,p[1].x,p[1].y)) //如果在一条直线上，则把远的放在前面 
return 1; 
else return -1; 
} 

其中的qsort函数包含在<stdlib.h>的头文件里，strcmp包含在<string.h>的头文件里

关于qsort的实现
你可以参见opensolaris的qsort.c的实现
访问这里



Main types and definitions
这里声明了编辑器使用的结构类型

typedef struct Point Point;
typedef struct Marker Marker;
typedef struct list_s Line;   /* This is evil! */
typedef struct Undo Undo;
typedef struct Region Region;
typedef struct Buffer Buffer;
typedef struct Window Window;
typedef struct Completion Completion;
typedef struct History History;
typedef struct Terminal Terminal;

行列标记

/* Point and Marker. */
struct Point {
  Line *p;                      /* Line pointer.(list) */ 
  size_t n;                     /* Line number. */
  size_t o;                     /* Offset. */
};