3 * Module: All Modules
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4 * Author(s): Chris Somers
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5 * Date: December 1, 1992
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8 minor mods by Alex Russell to simplify
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10 Must use memory model with FAR code
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16 #if !defined(__LARGE__) && !defined(__COMPACT__) && !defined(__HUGE__)
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17 #error Invalid memory model for compiling MEMORY.C
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26 // static globals --------------------------------
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28 static int ActiveEMList[MAXEMHANDLES];
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29 static unsigned int EMMSeg;
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31 // forward declarations ---------------------------------
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33 static int EMPresent(void);
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34 static int EMReady(void);
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35 static unsigned int GetEMMSeg(void);
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36 static int GetEMHandle(int NumPages);
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37 static int EMMap(int Handle, int LogPg, int PhyPg);
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38 static int FreeEMHandle(int Handle);
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39 static int GetNumPages(int Handle);
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40 static int EMStateSave(int Handle);
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41 static void EMStateRestore(int Handle);
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44 /********************************************************************/
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48 if (!EMPresent() || !EMReady()) return(NOTREADY);
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49 if (!(EMMSeg = GetEMMSeg())) return(NOTREADY); /*lint !e720 */
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51 } /* End of OpenEMM() */
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53 /********************************************************************/
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60 if (!EMMSeg) return;
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61 for (i = 0; i < MAXEMHANDLES; i++) {
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62 if (ActiveEMList[i]) {
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63 FreeEMHandle(ActiveEMList[i]);
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64 ActiveEMList[i] = 0;
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68 } /* End of CloseEMM() */
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70 /********************************************************************/
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75 return((EMMSeg) ? TRUE : FALSE); /* successfully opened? */
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76 } /* End of EMMInstalled() */
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78 /********************************************************************/
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84 unsigned long RtnVal = 0UL;
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87 mov ah,0x42 /* get EMM free page count */
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90 //js InternalError /* returns 80, 81, or 84 hex on error */
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91 mov Pages,bx /* number of unallocated 16K pages */
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93 RtnVal = ((unsigned long)Pages << 14); /* Pages * 16K rtns bytes*/
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98 } /* End of EMMCoreLeft() */
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100 /********************************************************************/
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103 EMMalloc(int *Handle, int Pages)
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106 char *RtnPtr = NULL;
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109 *Handle = NOTREADY;
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112 if ((Pages < 1) || (Pages > 1020)) {
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113 *Handle = VALUE_OUTF_RANGE;
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116 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i]); i++) ;
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117 if (i == MAXEMHANDLES) {
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118 *Handle = NOFREEITEMS;
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121 if ((ActiveEMList[i] = GetEMHandle(Pages)) > 0) {
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122 RtnPtr = MK_FP(EMMSeg, 0);
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124 *Handle = ActiveEMList[i];
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125 return((void far *)RtnPtr);
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126 } /* End of EMMalloc() */
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128 /********************************************************************/
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131 EMMRealloc(int Handle, int Pages)
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133 int RtnCode = FALSE;
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135 if (!EMMSeg || (Pages < 0) || (Pages > 1020)) {
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139 mov ah,0x51 /* change # of pages */
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144 //js NoGo /* returns 80 to 88 hex on error */
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151 } /* End of EMMRealloc() */
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153 /********************************************************************/
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156 EMMFree(int Handle)
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160 if (!EMMSeg) return;
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161 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
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162 if (i >= MAXEMHANDLES) return;
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165 if (FreeEMHandle(ActiveEMList[i])) break;
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167 ActiveEMList[i] = 0;
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168 } /* End of EMMFree() */
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170 /********************************************************************/
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172 int /* EMM map for application */
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173 MapEMM(int Handle, int Start, int Pages)
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177 if (!EMMSeg) return(NOTREADY);
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178 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
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179 if (i == MAXEMHANDLES) return (NO_DATA);
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180 if ((GetNumPages(Handle) < Pages) || (Pages < 1) || (Pages > 4)) {
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181 return (VALUE_OUTF_RANGE);
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183 for (i = Start; i < Start + Pages; i++) {
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184 if (!EMMap(Handle, i, i - Start)) return(NO_DATA);
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187 } /* End of MapEMM() */
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189 /********************************************************************/
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191 void /* EMM unmap for application */
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192 UnmapEMM(int Handle, int Start, int Pages)
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196 if (!EMMSeg) return;
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197 for (i = 0; (i < MAXEMHANDLES) && (ActiveEMList[i] != Handle); i++) ;
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198 if (i == MAXEMHANDLES) return;
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200 if ((Pages < 1) || (j > 4)) return;
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202 for (i = Start; i < j; i++) {
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203 EMMap(Handle, NONE, i);
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205 } /* End of UnmapEMM() */
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207 /********************************************************************/
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209 int /* EMM map for devices - saves EMM state */
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210 UseEMM(int Handle, int Start, int Pages)
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212 EMStateSave(Handle);
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213 return(MapEMM(Handle, Start, Pages));
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214 } /* End of UseEMM() */
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216 /********************************************************************/
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218 void /* EMM unmap for devices - restores EMM state */
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219 SaveEMM(int Handle, int Start, int Pages)
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221 UnmapEMM(Handle, Start, Pages);
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222 EMStateRestore(Handle);
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223 } /* End of SaveEMM() */
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225 /********************************************************************/
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231 char EMName[] = "EMMXXXX0";
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234 _asm { /* can be replaced with getvect() */
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236 mov ax,0x3567 /* get vector for int 67h */
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242 t = MK_FP(Segment, 0x0A); /* point to driver name */
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244 for (i = 0; (i < 8) && (*s++ == *t++); i++) ; /* strncmp equivalent */
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246 if (i == 8) return(TRUE);
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248 } /*End of EMPresent() */
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250 /********************************************************************/
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256 mov ah,0x40 /* get EM Manager Status */
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259 //jns Ready /* returns 80, 81, or 84 hex on error */
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265 } /* End of EMReady() */
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267 /********************************************************************/
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269 static unsigned int
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272 unsigned int EMSegment;
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275 mov ah,0x41 /* get EMM page frame segment */
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278 //js NotReady /* returns 80, 81, or 84 hex on error */
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281 return(EMSegment); /*lint !e530 */
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285 } /* End of GetEMMSeg() */
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287 /********************************************************************/
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290 GetEMHandle(int NumPages)
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295 mov ah,0x43 /* get handle and allocate EM */
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296 mov bx,NumPages /* number of 16K pages to allocate */
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298 or ah,ah /* returns 80 to 89 hex on error */
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300 mov NewHandle,dx /* retrieve handle */
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306 } /* End of GetEMHandle() */
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308 /********************************************************************/
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311 EMMap(int Handle, int LogPg, int PhyPg)
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313 int RtnCode = NO_DATA;
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316 mov ax,PhyPg /* physical page: 0 - 3 in AL only */
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317 mov ah,0x44 /* map logical to physical page */
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318 mov bx,LogPg /* logical page: 0 - 1020 */
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321 or ah,ah /* returns 80 to 8B hex on error */
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328 } /* End of EMMap() */
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330 /********************************************************************/
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333 FreeEMHandle(int Handle)
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336 mov ah,0x45 /* free handle and deallocate EM */
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339 or ah,ah /* returns 80 to 86 hex on error */
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344 //NotFreed: /* must retry if unsuccessful */
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346 } /* End of FreeEMHandle() */
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348 /********************************************************************/
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351 GetNumPages(int Handle)
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356 mov ah,0x4C /* get allocated pages for Handle */
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359 or ah,ah /* returns 80 to 84 hex on error */
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366 } /* End of GetNumPages() */
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368 /********************************************************************/
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371 EMStateSave(int Handle)
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373 int RtnCode = NO_MEMORY;
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375 mov ah,0x47 /* save page map under Handle */
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379 //js Unsaved /* out of save space error */
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385 } /* End of EMStateSave() */
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387 /********************************************************************/
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390 EMStateRestore(int Handle)
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393 mov ah,0x48 /* restore page map for Handle */
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395 int 0x67 /* ignore error */
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397 } /* End of EMStateRestore() */
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