/*****************************************************************************/ /* */ /* em.h */ /* */ /* API for extended memory access */ /* */ /* */ /* */ /* (C) 2002-2012, Ullrich von Bassewitz */ /* Roemerstrasse 52 */ /* D-70794 Filderstadt */ /* EMail: uz@cc65.org */ /* */ /* */ /* 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 /* 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 */ #define EM_ERR_INSTALLED 5 /* A driver is already installed */ /* Parameters for the em_copy_... functions. NOTE: The first seven bytes ** have the same order and alignment as needed for the Commodore REU, so ** don't change the order without changing the assembler file that defines ** the struct offsets and the code in the REU driver. */ struct em_copy { void* buf; /* Memory buffer to copy from or to */ unsigned char offs; /* Offset into page */ unsigned page; /* Starting page 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_driver (const char* driver); /* Load and install an extended memory driver. Return an error code. */ unsigned char em_unload (void); /* Uninstall, then unload the currently loaded driver. */ unsigned char __fastcall__ em_install (const void* driver); /* Install an already loaded driver. Return an error code. */ unsigned char em_uninstall (void); /* Uninstall the currently loaded driver and return an error code. ** Note: This call does not free allocated memory. */ 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. Note: Without calling ** em_commit, the old contents of the memory window may be lost! */ void* __fastcall__ em_use (unsigned page); /* Tell the driver that the memory window is associated with a given page. ** This call is very similar to em_map. The difference is that the driver ** does not necessarily transfer the current contents of the extended ** memory into the returned window. If you're going to just write to the ** window and the current contents of the window are invalid or no longer ** use, this call may perform better than em_map. */ void em_commit (void); /* Commit changes in the memory window to extended storage. If the contents ** of the memory window have been changed, these changes may be lost if ** em_map, em_copyfrom or em_copyto are called without calling em_commit ** first. Note: Not calling em_commit does not mean that the changes are ** discarded, it does just mean that some drivers will discard the changes. */ 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