3 * Module: All Modules
\r
4 * Author(s): Chris Somers
\r
5 * Date: December 1, 1992
\r
8 minor mods by Alex Russell to simplify
\r
10 Must use memory model with FAR code
\r
16 #if !defined(__LARGE__) && !defined(__COMPACT__) && !defined(__HUGE__)
\r
17 #error Invalid memory model for compiling MEMORY.C
\r
26 //static globals --------------------------------
\r
28 static int ActiveEMList[MAXEMHANDLES];
\r
29 static unsigned int EMMSeg;
\r
31 //forward declarations ---------------------------------
\r
33 static int EMPresent(void);
\r
34 static int EMReady(void);
\r
35 static unsigned int GetEMMSeg(void);
\r
36 static int GetEMHandle(int NumPages);
\r
37 static int EMMap(int Handle, int LogPg, int PhyPg);
\r
38 static int FreeEMHandle(int Handle);
\r
39 static int GetNumPages(int Handle);
\r
40 static int EMStateSave(int Handle);
\r
41 static void EMStateRestore(int Handle);
\r
44 /********************************************************************/
\r
48 if (!EMPresent() || !EMReady()) return(NOTREADY);
\r
49 if (!(EMMSeg = GetEMMSeg())) return(NOTREADY); /*lint !e720 */
\r
51 } /* End of OpenEMM() */
\r
53 /********************************************************************/
\r
60 if (!EMMSeg) return;
\r
61 for (i = 0; i < MAXEMHANDLES; i++) {
\r
62 if (ActiveEMList[i]) {
\r
63 FreeEMHandle(ActiveEMList[i]);
\r
64 ActiveEMList[i] = 0;
\r
68 } /* End of CloseEMM() */
\r
70 /********************************************************************/
\r
75 return((EMMSeg) ? TRUE : FALSE); /* successfully opened? */
\r
76 } /* End of EMMInstalled() */
\r
78 /********************************************************************/
\r
84 unsigned long RtnVal = 0UL;
\r
87 mov ah,0x42 /* get EMM free page count */
\r
90 js InternalError /* returns 80, 81, or 84 hex on error */
\r
91 mov Pages,bx /* number of unallocated 16K pages */
95 RtnVal = ((unsigned long)Pages << 14); /* Pages * 16K rtns bytes*/
\r
99 } /* End of EMMCoreLeft() */
\r
101 /********************************************************************/
\r
104 EMMalloc(int *Handle, int Pages)
\r
107 char *RtnPtr = NULL;
\r
110 *Handle = NOTREADY;
\r
113 if ((Pages < 1) || (Pages > 1020)) {
\r
114 *Handle = VALUE_OUTF_RANGE;
\r
117 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i]); i++) ;
\r
118 if (i == MAXEMHANDLES) {
\r
119 *Handle = NOFREEITEMS;
\r
122 if ((ActiveEMList[i] = GetEMHandle(Pages)) > 0) {
\r
123 RtnPtr = MK_FP(EMMSeg, 0);
\r
125 *Handle = ActiveEMList[i];
\r
126 return((void far *)RtnPtr);
\r
127 } /* End of EMMalloc() */
\r
129 /********************************************************************/
\r
132 EMMRealloc(int Handle, int Pages)
\r
134 int RtnCode = FALSE;
\r
136 if (!EMMSeg || (Pages < 0) || (Pages > 1020)) {
\r
140 mov ah,0x51 /* change # of pages */
\r
145 js NoGo /* returns 80 to 88 hex on error */
153 } /* End of EMMRealloc() */
\r
155 /********************************************************************/
\r
158 EMMFree(int Handle)
\r
162 if (!EMMSeg) return;
\r
163 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
\r
164 if (i >= MAXEMHANDLES) return;
\r
167 if (FreeEMHandle(ActiveEMList[i])) break;
\r
169 ActiveEMList[i] = 0;
\r
170 } /* End of EMMFree() */
\r
172 /********************************************************************/
\r
174 int /* EMM map for application */
\r
175 MapEMM(int Handle, int Start, int Pages)
\r
179 if (!EMMSeg) return(NOTREADY);
\r
180 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
\r
181 if (i == MAXEMHANDLES) return (NO_DATA);
\r
182 if ((GetNumPages(Handle) < Pages) || (Pages < 1) || (Pages > 4)) {
\r
183 return (VALUE_OUTF_RANGE);
\r
185 for (i = Start; i < Start + Pages; i++) {
\r
186 if (!EMMap(Handle, i, i - Start)) return(NO_DATA);
\r
189 } /* End of MapEMM() */
\r
191 /********************************************************************/
\r
193 void /* EMM unmap for application */
\r
194 UnmapEMM(int Handle, int Start, int Pages)
\r
198 if (!EMMSeg) return;
\r
199 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
\r
200 if (i == MAXEMHANDLES) return;
\r
202 if ((Pages < 1) || (j > 4)) return;
\r
204 for (i = Start; i < j; i++) {
\r
205 EMMap(Handle, NONE, i);
\r
207 } /* End of UnmapEMM() */
\r
209 /********************************************************************/
\r
211 int /* EMM map for devices - saves EMM state */
\r
212 UseEMM(int Handle, int Start, int Pages)
\r
214 EMStateSave(Handle);
\r
215 return(MapEMM(Handle, Start, Pages));
\r
216 } /* End of UseEMM() */
\r
218 /********************************************************************/
\r
220 void /* EMM unmap for devices - restores EMM state */
\r
221 SaveEMM(int Handle, int Start, int Pages)
\r
223 UnmapEMM(Handle, Start, Pages);
\r
224 EMStateRestore(Handle);
\r
225 } /* End of SaveEMM() */
\r
227 /********************************************************************/
\r
233 char EMName[] = "EMMXXXX0";
\r
236 _asm { /* can be replaced with getvect() */
\r
238 mov ax,0x3567 /* get vector for int 67h */
\r
244 t = MK_FP(Segment, 0x0A); /* point to driver name */
\r
246 for (i = 0; (i < 8) && (*s++ == *t++); i++) ; /* strncmp equivalent */
\r
248 if (i == 8) return(TRUE);
\r
250 } /*End of EMPresent() */
\r
252 /********************************************************************/
\r
258 mov ah,0x40 /* get EM Manager Status */
\r
261 jns Ready /* returns 80, 81, or 84 hex on error */
269 } /* End of EMReady() */
\r
271 /********************************************************************/
\r
273 static unsigned int
\r
276 unsigned int EMSegment;
\r
279 mov ah,0x41 /* get EMM page frame segment */
\r
282 js NotReady /* returns 80, 81, or 84 hex on error */
\r
287 return(EMSegment); /*lint !e530 */
\r
290 // return(NOTREADY);
\r
291 } /* End of GetEMMSeg() */
\r
293 /********************************************************************/
\r
296 GetEMHandle(int NumPages)
\r
301 mov ah,0x43 /* get handle and allocate EM */
\r
302 mov bx,NumPages /* number of 16K pages to allocate */
\r
304 or ah,ah /* returns 80 to 89 hex on error */
\r
306 mov NewHandle,dx /* retrieve handle */
313 // return(NO_DATA);
\r
314 } /* End of GetEMHandle() */
\r
316 /********************************************************************/
\r
319 EMMap(int Handle, int LogPg, int PhyPg)
\r
321 int RtnCode = NO_DATA;
\r
324 mov ax,PhyPg /* physical page: 0 - 3 in AL only */
\r
325 mov ah,0x44 /* map logical to physical page */
\r
326 mov bx,LogPg /* logical page: 0 - 1020 */
\r
329 or ah,ah /* returns 80 to 8B hex on error */
\r
338 } /* End of EMMap() */
\r
340 /********************************************************************/
\r
343 FreeEMHandle(int Handle)
\r
346 mov ah,0x45 /* free handle and deallocate EM */
\r
349 or ah,ah /* returns 80 to 86 hex on error */
\r
351 NotFreed: /* must retry if unsuccessful */
356 //NotFreed: /* must retry if unsuccessful */
\r
357 // return(NO_DATA);
\r
358 } /* End of FreeEMHandle() */
\r
360 /********************************************************************/
\r
363 GetNumPages(int Handle)
\r
368 mov ah,0x4C /* get allocated pages for Handle */
\r
371 or ah,ah /* returns 80 to 84 hex on error */
\r
380 } /* End of GetNumPages() */
\r
382 /********************************************************************/
\r
385 EMStateSave(int Handle)
\r
387 int RtnCode = NO_MEMORY;
\r
389 mov ah,0x47 /* save page map under Handle */
\r
393 js Unsaved /* out of save space error */
401 } /* End of EMStateSave() */
\r
403 /********************************************************************/
\r
406 EMStateRestore(int Handle)
\r
409 mov ah,0x48 /* restore page map for Handle */
\r
411 int 0x67 /* ignore error */
\r
413 } /* End of EMStateRestore() */
\r