improve some memory functions.

ChangeLog

@@ -1,3 +1,28 @@
+2000-05-21  OKUJI Yoshinori  <okuji@gnu.org>
+
+	* stage2/asm.S (set_int13_handler): Don't use MBI to get the
+	lower memory size. Instead, decrease it in the BIOS memory
+	directly and set %eax to it, since MBI.MEM_LOWER may not be the
+	same as [0x413] any longer due to the previous change.
+
+	* grub/asmstub.c (CONVENTIONAL_MEMSIZE): Changed to 640 * 1024
+	from 640. You didn't like the inconsistency between
+	EXTENDED_MEMSIZE and CONVENTIONAL_MEMSIZE, did you?
+	(get_memsize): Return CONVENTIONAL_MEMSIZE >> 10 instead of
+	CONVENTIONAL_MEMSIZE, if TYPE is zero.
+	(get_eisamemsize): Return EXTENDED_MEMSIZE >> 10 instead of
+	EXTENDED_MEMSIZE / 1024. Just a cosmetic change.
+	(MMAR_DESC_LENGTH): New macro. Defined as 20.
+	(get_mmap_entry): Define a new variable DESC_TABLE statically, 
+	and copy the CONTth entry to *DESC if CONT is a correct index.
+	
+2000-05-21  Chip Salzenberg  <chip@valinux.com>
+
+	* stage2/common.c (mmap_avail_at): New function, abstracted out
+	of init_bios_info, to scan E820 memory map.
+	(init_bios_info): Use mmap_avail_at for _both_ MBI.MEM_UPPER and
+	MBI.MEM_LOWER.
+
 2000-05-17  OKUJI Yoshinori  <okuji@gnu.org>
 
 	Update the network support to Etherboot-4.6.1.

THANKS

@@ -11,6 +11,7 @@ Andrew Clausen <clausen@gnu.org>
 Bradford Hovinen <hovinen@redrose.net>
 Brian Brunswick <brian@skarpsey.demon.co.uk>
 Bryan Ford <baford@cs.utah.edu>
+Chip Salzenberg <chip@valinux.com>
 Dan J. Walters <djw@cs.utexas.edu>
 Edmund GRIMLEY EVANS <edmundo@rano.demon.co.uk>
 Edward Killips <ekillips@triton.net>

grub/asmstub.c

@@ -73,7 +73,7 @@ int grub_stage2 (void);
 
 /* Simulated memory sizes. */
 #define EXTENDED_MEMSIZE (3 * 1024 * 1024)	/* 3MB */
-#define CONVENTIONAL_MEMSIZE (640) /* 640kB */
+#define CONVENTIONAL_MEMSIZE (640 * 1024)	/* 640kB */
 
 /* Simulated disk sizes. */
 #define DEFAULT_FD_CYLINDERS	80
@@ -685,9 +685,9 @@ int
 get_memsize (int type)
 {
   if (! type)
-    return CONVENTIONAL_MEMSIZE;
+    return CONVENTIONAL_MEMSIZE >> 10;
   else
-    return EXTENDED_MEMSIZE;
+    return EXTENDED_MEMSIZE >> 10;
 }
 
 
@@ -698,7 +698,7 @@ get_memsize (int type)
 int
 get_eisamemsize (void)
 {
-  return (EXTENDED_MEMSIZE / 1024);
+  return (EXTENDED_MEMSIZE >> 10);
 }
 
 
@@ -707,6 +707,8 @@ get_eisamemsize (void)
 #define MMAR_DESC_TYPE_ACPI_RECLAIM 3 /* usable by OS after reading ACPI */
 #define MMAR_DESC_TYPE_ACPI_NVS 4 /* required to save between NVS sessions */
 
+#define MMAR_DESC_LENGTH	20
+
 /* Fetch the next entry in the memory map and return the continuation
    value.  DESC is a pointer to the descriptor buffer, and CONT is the
    previous continuation value (0 to get the first entry in the
@@ -714,19 +716,49 @@ get_eisamemsize (void)
 int
 get_mmap_entry (struct mmar_desc *desc, int cont)
 {
-  if (! cont)
+  /* Record the memory map statically.  */
+  static struct mmar_desc desc_table[] =
   {
-      /* First entry, located at 1MB. */
+    /* The conventional memory.  */
-      desc->desc_len = sizeof (*desc) - sizeof (desc->desc_len);
+    {
-      desc->addr = 1024 * 1024;
+      MMAR_DESC_LENGTH,
-      desc->length = EXTENDED_MEMSIZE;
+      0,
-      desc->type = MMAR_DESC_TYPE_AVAILABLE;
+      CONVENTIONAL_MEMSIZE,
+      MMAR_DESC_TYPE_AVAILABLE
+    },
+    /* BIOS RAM and ROM (such as video memory).  */
+    {
+      MMAR_DESC_LENGTH,
+      CONVENTIONAL_MEMSIZE,
+      0x100000 - CONVENTIONAL_MEMSIZE,
+      MMAR_DESC_TYPE_RESERVED
+    },
+    /* The extended memory.  */
+    {
+      MMAR_DESC_LENGTH,
+      0x100000,
+      EXTENDED_MEMSIZE,
+      MMAR_DESC_TYPE_AVAILABLE
+    }
+  };
+  
+  int num = sizeof (desc_table) / sizeof (*desc_table);
+
+  if (cont < 0 || cont >= num)
+    {
+      /* Should not happen.  */
+      desc->desc_len = 0;
     }
   else
     {
-      /* No more entries, so give an error. */
+      /* Copy the entry.  */
-      desc->desc_len = 0;
+      *desc = desc_table[cont++];
+
+      /* If the next entry exists, return the index.  */
+      if (cont < num)
+	return cont;
     }
+  
   return 0;
 }
 

stage2/asm.S

@@ -564,13 +564,12 @@ ENTRY(set_int13_handler)
 	movw	2(%edi), %ax
 	movw	%ax, ABS(int13_segment)
 	
-	/* get the lower memory size */
-	movl	$EXT_C(mbi), %edi
-	movl	4(%edi), %eax
 	/* decrease the lower memory size and set it to the BIOS memory */
-	decl	%eax
 	movl	$0x413, %edi
-	movw	%ax, (%edi)
+	decw	(%edi)
+	xorl	%eax, %eax
+	movw	(%edi), %ax
+	
 	/* compute the segment */
 	shll	$6, %eax
 

stage2/common.c

@@ -90,13 +90,42 @@ static struct AddrRangeDesc fakemap[3] =
   {20, 0x100000, 0, 0, 0, MB_ARD_MEMORY},
   {20, 0x1000000, 0, 0, 0, MB_ARD_MEMORY}
 };
-#endif /* STAGE1_5 */
 
+/* A big problem is that the memory areas aren't guaranteed to be:
+   (1) contiguous, (2) sorted in ascending order, or (3) non-overlapping.
+   Thus this kludge.  */
+static unsigned long
+mmap_avail_at (unsigned long bottom)
+{
+  unsigned long top, addr;
+  int cont;
   
-/*
+  top = bottom;
- *  This queries for BIOS information.
+  do
- */
+    {
+      for (cont = 0, addr = mbi.mmap_addr;
+	   addr < mbi.mmap_addr + mbi.mmap_length;
+	   addr += *((unsigned long *) addr) + 4)
+	{
+	  struct AddrRangeDesc *desc = (struct AddrRangeDesc *) addr;
 	  
+	  if (desc->BaseAddrHigh == 0
+	      && desc->Type == MB_ARD_MEMORY
+	      && desc->BaseAddrLow <= top
+	      && desc->BaseAddrLow + desc->LengthLow > top)
+	    {
+	      top = desc->BaseAddrLow + desc->LengthLow;
+	      cont++;
+	    }
+	}
+    }
+  while (cont);
+  
+  return top - bottom;
+}
+#endif /* ! STAGE1_5 */
+
+/* This queries for BIOS information.  */
 void
 init_bios_info (void)
 {
@@ -140,7 +169,7 @@ init_bios_info (void)
     {
       cont = get_mmap_entry ((void *) addr, cont);
 
-      /* If the returned buffer's base is zero, quit. */
+      /* If the returned buffer's length is zero, quit. */
       if (! *((unsigned long *) addr))
 	break;
 
@@ -152,41 +181,16 @@ init_bios_info (void)
   if (mbi.mmap_length)
     {
       /*
-       *  This is to get the upper memory up to the first memory
+       *  This is to get the lower memory, and upper memory (up to the
-       *  hole into the "mbi.mem_upper" element, for OS's that
+       *  first memory hole), into the "mbi.mem_{lower,upper}"
-       *  don't care about the memory map, but might care about
+       *  elements.  This is for OS's that don't care about the memory
-       *  RAM above 64MB.
+       *  map, but might care about total RAM available.
-       *
-       *  A big problem is that the memory areas aren't guaranteed
-       *  to be:  (1) contiguous, (2) sorted in ascending order, or
-       *  (3) non-overlapping.
        */
-      memtmp = 0x100000;
+      mbi.mem_lower = mmap_avail_at (0) >> 10;
-
+      mbi.mem_upper = mmap_avail_at (0x100000) >> 10;
-      do
-	{
-	  for (cont = 0, addr = mbi.mmap_addr;
-	       addr < mbi.mmap_addr + mbi.mmap_length;
-	       addr += *((unsigned long *) addr) + 4)
-	    {
-	      if (((struct AddrRangeDesc *) addr)->BaseAddrHigh == 0
-		  && ((struct AddrRangeDesc *) addr)->Type == MB_ARD_MEMORY
-		  && ((struct AddrRangeDesc *) addr)->BaseAddrLow <= memtmp
-		  && (((struct AddrRangeDesc *) addr)->BaseAddrLow
-		      + ((struct AddrRangeDesc *) addr)->LengthLow) > memtmp)
-		{
-		  memtmp = (((struct AddrRangeDesc *) addr)->BaseAddrLow
-			    + ((struct AddrRangeDesc *) addr)->LengthLow);
-		  cont++;
-		}
-	    }
-	}
-      while (cont);
-
-      mbi.mem_upper = (memtmp - 0x100000) >> 10;
 
       /* Find the maximum available address. Ignore any memory holes.  */
-      for (addr = mbi.mmap_addr;
+      for (memtmp = 0, addr = mbi.mmap_addr;
 	   addr < mbi.mmap_addr + mbi.mmap_length;
 	   addr += *((unsigned long *) addr) + 4)
 	{