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New API for access to extended memory

git-svn-id: svn://svn.cc65.org/cc65/trunk@1675 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2002-11-29 14:40:31 +00:00
parent 702c94db48
commit a1a3022b5c
2 changed files with 212 additions and 0 deletions

119
include/em.h Normal file
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/*****************************************************************************/
/* */
/* em.h */
/* */
/* API for extended memory access */
/* */
/* */
/* */
/* (C) 2002 Ullrich von Bassewitz */
/* Wacholderweg 14 */
/* D-70597 Stuttgart */
/* EMail: uz@musoftware.de */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#ifndef _EM_H
#define _EM_H
/*****************************************************************************/
/* Definitions */
/*****************************************************************************/
/* Size of an extended memory page */
#define EM_PAGE_SIZE 256
/* Driver constants */
#define EM_DRV_DETECT 0
/* Error codes */
#define EM_ERR_OK 0 /* No error */
#define EM_ERR_NO_DRIVER 1 /* No driver available */
#define EM_ERR_CANNOT_LOAD 2 /* Error loading driver */
#define EM_ERR_INV_DRIVER 3 /* Invalid driver */
#define EM_ERR_NO_DEVICE 4 /* Device (hardware) not found */
/* Parameters for the em_copy_... functions */
struct em_copy {
unsigned page; /* Starting page to copy from or to */
unsigned char offs; /* Offset into page */
void* buf; /* Memory buffer to copy from or to */
unsigned count; /* Number of bytes to copy */
unsigned char unused; /* Make the size 8 bytes */
};
/*****************************************************************************/
/* Functions */
/*****************************************************************************/
unsigned char __fastcall__ em_load (unsigned char driver);
/* Load the extended memory driver and return an error code. */
unsigned char __fastcall__ em_load_driver (const char* driver);
/* Load an extended memory driver and return an error code */
unsigned char em_unload (void);
/* Unload the currently loaded driver. */
unsigned em_pagecount (void);
/* Return the total number of 256 byte pages available in extended memory. */
void* __fastcall__ em_map (unsigned page);
/* Unmap the current page from memory and map a new one. The function returns
* a pointer to the location of the page in memory.
*/
void* __fastcall__ em_mapclean (unsigned page);
/* Unmap the current page from memory and map a new one. The function returns
* a pointer to the location of the page in memory. This function differs from
* em_map_page() in that it will discard the contents of the currently mapped
* page, assuming that the page has not been modified or that the modifications
* are no longer needed, if this leads to better performance. NOTE: This does
* NOT mean that the contents of currently mapped page are always discarded!
*/
void __fastcall__ em_copyfrom (const struct em_copy* copy_data);
/* Copy from extended into linear memory. Note: This may invalidate the
* currently mapped page.
*/
void __fastcall__ em_copyto (const struct em_copy* copy_data);
/* Copy from linear into extended memory. Note: This may invalidate the
* currently mapped page.
*/
/* End of em.h */
#endif

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/*****************************************************************************/
/* */
/* em-kernel.h */
/* */
/* Internally used EM functions */
/* */
/* */
/* */
/* (C) 2002 Ullrich von Bassewitz */
/* Wacholderweg 14 */
/* D-70597 Stuttgart */
/* EMail: uz@musoftware.de */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#ifndef _EM_KERNEL_H
#define _EM_KERNEL_H
/*****************************************************************************/
/* Data */
/*****************************************************************************/
/* A structure that describes the header of an extended memory driver loaded
* into memory.
*/
typedef struct {
/* Driver header */
char id[3]; /* Contains 0x65, 0x6d, 0x64 ("emd") */
unsigned char version; /* Interface version */
/* Jump vectors. Note that these are not C callable */
void* install; /* INSTALL routine */
void* deinstall; /* DEINSTALL routine */
void* pagecount; /* PAGECOUNT routine */
void* map; /* MAP routine */
void* mapclean; /* MAPCLEAN routine */
void* copyfrom; /* COPYFROM routine */
void* copyto; /* COPYTO routine */
} em_drv_header;
/* EM kernel variables */
extern em_drv_header* em_drv; /* Pointer to driver */
/*****************************************************************************/
/* Functions */
/*****************************************************************************/
unsigned char __fastcall__ em_install (void* driver);
/* Install the driver once it is loaded, return an error code. */
void __fastcall__ em_deinstall (void);
/* Deinstall the driver before unloading it */
/* End of em-kernel.h */
#endif