Support for switches=/e[[:]nnnn] and for moving the EBDA (with Lucho)

git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@675 6ac86273-5f31-0410-b378-82cca8765d1b

kernel/config.c

@@ -70,6 +70,7 @@ struct config Config = {
       , 0                       /* amount required memory */
       , 0                       /* pointer to loaded data */
       , 0                       /* strategy for command.com is low by default */
+      , 0xFFFF                  /* default value for switches=/E:nnnn */
 };
                         /* MSC places uninitialized data into COMDEF records,
                            that end up in DATA segment. this can't be tolerated
@@ -285,6 +286,7 @@ void PreConfig(void)
 void PreConfig2(void)
 {
   struct sfttbl FAR *sp;
+  unsigned ebda_size;
 
   /* initialize NEAR allocated things */
 
@@ -305,15 +307,24 @@ void PreConfig2(void)
 
   base_seg = LoL->first_mcb = FP_SEG(AlignParagraph((BYTE FAR *) DynLast() + 0x0f));
 
+  ebda_size = ebdasize();
+  if (ebda_size > Config.ebda2move)
+    ebda_size = Config.ebda2move;
+  ram_top += ebda_size / 1024;
+
   /* We expect ram_top as Kbytes, so convert to paragraphs */
   mcb_init(base_seg, ram_top * 64 - LoL->first_mcb - 1, MCB_LAST);
-  if (UmbState == 2)
-    umb_init();    
 
   sp = LoL->sfthead;
   sp = sp->sftt_next = KernelAlloc(sizeof(sftheader) + 3 * sizeof(sft), 'F', 0);
   sp->sftt_next = (sfttbl FAR *) - 1;
   sp->sftt_count = 3;
+
+  if (ebda_size)  /* move the Extended BIOS Data Area from top of RAM here */
+    movebda(ebda_size, FP_SEG(KernelAlloc(ebda_size, 'I', 0)));
+
+  if (UmbState == 2)
+    umb_init();
 }
 
 /* Do third pass initialization.                                        */
@@ -991,6 +1002,28 @@ STATIC VOID CfgSwitches(BYTE * pLine)
       case 'F':
         InitKernelConfig.SkipConfigSeconds = 0;
         break;
+      case 'E': /* /E[[:]nnnn]  Set the desired EBDA amount to move in bytes */
+        {       /* Note that if there is no EBDA, this will have no effect */
+          char *p;
+          int n = 0;
+          if (*++pLine == ':')
+            pLine++;                    /* skip optional separator */
+          if ((p = GetNumArg(pLine, &n)) == 0) {
+            Config.ebda2move = 0;
+            break;
+          }
+          pLine = p - 1;              /* p points past number */
+          /* allowed values: [0..1024] bytes, multiples of 16
+           * e.g. AwardBIOS: 48, AMIBIOS: 1024
+           * (Phoenix, MRBIOS, Unicore = ????)
+           */
+          if (n >= 48 && n <= 1024)
+          {
+            Config.ebda2move = (n + 15) & 0xfff0;
+            break;
+          }
+          /* else fall through (failure) */
+        }
       default:
         CfgFailure(pLine);
       }
@@ -1349,7 +1382,6 @@ void FAR * KernelAlloc(size_t nBytes, char type, int mode)
     /* prealloc */
     lpTop = MK_FP(FP_SEG(lpTop) - nPara, FP_OFF(lpTop));
     return AlignParagraph(lpTop);
-    
   }
   else
   {

kernel/init-mod.h

@@ -109,6 +109,8 @@ struct config {
   /* where the loaded data is for PostConfig() */
   UBYTE cfgP_0_startmode;
   /* load command.com high or not */
+  unsigned ebda2move;
+  /* value for switches=/E:nnnn */
 };
 
 extern struct config Config;
@@ -139,7 +141,9 @@ int MoveKernelToHMA(void);
 VOID FAR * HMAalloc(COUNT bytesToAllocate);
 
 /* initoem.c */
-UWORD init_oem(void);
+unsigned init_oem(void);
+void movebda(int bytes, unsigned new_seg);
+unsigned ebdasize(void);
 
 /* intr.asm */
 

kernel/initoem.c

@@ -35,20 +35,38 @@ static BYTE *RcsId =
     "$Id$";
 #endif
 
-UWORD init_oem(void)
+#define EBDASEG 0x40e
-{
+#define RAMSIZE 0x413
-  UWORD top_k = 0;
 
-#ifdef __TURBOC__
+unsigned init_oem(void)
-  __int__(0x12);
+{
-  top_k = _AX;
+  iregs r;
-#elif defined(I86)
+  init_call_intr(0x12, &r);
-  asm
+  return r.a.x;
-  {
-    int 0x12;
-    mov top_k, ax;
-  }
-#endif
-  return top_k;
 }
 
+void movebda(size_t bytes, unsigned new_seg)
+{
+  unsigned old_seg = peek(0, EBDASEG);
+  fmemcpy(MK_FP(new_seg, 0), MK_FP(old_seg, 0), bytes);
+  poke(0, EBDASEG, new_seg);
+  poke(0, RAMSIZE, ram_top);
+}
+
+unsigned ebdasize(void)
+{
+  unsigned ebdaseg = peek(0, EBDASEG);
+  unsigned ramsize = ram_top;
+
+  if (ramsize * 64 == ebdaseg && ramsize < 640 && peek(0, RAMSIZE) == ramsize)
+  {
+    unsigned ebdasz = peekb(ebdaseg, 0);
+
+    /* sanity check: is there really no more than 63 KB?
+     * must be at 640k (all other values never seen and are untested)
+     */
+    if (ebdasz <= 63 && ramsize + ebdasz == 640)
+      return ebdasz * 1024U;
+  }
+  return 0;
+}