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Description of commands used by hdd.h

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    s32 dd_create(void);

    

	Generates the Disk processing thread and performs the 

	necessary initialization. It returns -1 with normal 

	termination; if it has already been called, it does 

	nothing and returns 0.  By specifying the following 

	options when compiling dd.c, the operation of this 

	function can be changed as described. 



	Option: 

        START_FROM_CASSETTE      

                                

	Effect: 

	Calls LeoCJCreateLeoManager rather than 

	LeoCreateLeoManager. Checks the Disk Drive connection.  

	Cancels reset status. 

        

	START_FROM_CASSETTE suboptions: 

            NO_USE_RTC:  The RTC is not checked. 

            NEED_DISK:   Prompts for Disk insertion if no Disk 

			 inserted at initialization. 





    s32 dd_exec( TMessage4dd * msg );

       

	Posts commands to the Disk thread.  Serves as an 

	asynchronous function if msg->retQ is set.  In this case, 

	msg must be received by dd_checkGate(). Note that retQ 

	cannot be a temporary local variable. For information on 

	commands that can be posted, see command.txt.





    s32 dd_checkGate( TMessage4dd * msg );  



	Returns -1 if processing for a Disk thread started by 

	dd_exec( ) has been completed and 0 if processing is still

	being performed.  This function does not block the thread.

	It merely indicates whether the next call to dd_exec() can

	be issued.  Only when the return value of this function is

	true does the Disk thread store a meaningful value in msg. 





    s32 dd_thaw(s32 target_err);



	Resumes error handling in a suspended Disk thread.

	target_err is used for an integrity check and must match 

	dd_getStatus( )->errno.  It also must correspond one for 

	one with dd_freeze(), a static function in this module. 





    void dd_flush(void);



	An auxiliary function necessary to enable functioning of 

	dd_wait( ), the wait function for the Disk thread.  When 

	using the hdd.h module, this function should be called 

	from the main scheduler for each frame. 





    TDDStatus  *dd_getStatus(void);



        Returns Disk thread information. 





    s32 dd_saveID(LEODiskID * det);



        Sets det as the current Disk ID.  Used mainly when a Disk

	is to be changed. 





    s32 dd_driveExist(void);



        Returns 1 if a drive is connected. 

 



    u32 dd_getVersion(void);



        Returns version information obtained by LeoInquiry as

	32-byte data. 

        



    s32 dd_getBlockSize(s32 lba,s32 size);



	A LeoLBAToByte() parameter.  Returns the number of bytes

	in size blocks, beginning from lba. 



    void dd_change_mode_USA(void);

    

	When creating cassette-startup Disk games for use in the

	U.S., call this function before executing dd_create().





    void dd_errHook(s32 func_no , s32 err_no , s32 count );



	A function for debugging the module itself.  Please ensure

	that func_no references leofunc_t in hdd_internal.h.

	Subsequently, when the Leo function specified by func_no

	is executed, the error err_no is forcibly returned count

	number of times.  With each forced error, count is passed

	1.

       

	Only one Leo function can be hooked at a time. 

    

    



The following are static functions, but they should be used only

after being modified by the application.



 

    s32 dd_checkSum(void);

    

	Describes a method of data checking when a RAM area read

	is performed. This method must correspond with the write

	method of dd_makeSum().





    s32 dd_makeSum(void);

        

	Prescribes the data format for the RAM area.  The format

	corresponds with the data check of dd_checkSum().





    s32 dd_restoreData(void);



	Prescribes the restoration method used when RAM area data

	are destroyed.