----------------------------------------------------------------------
Patch name: VBE Linear Frame Buffer support
Author: Jeroen Janssen
Date:   24 March 2002
RCS Id: $Id: patch.vbe-lfb,v 1.2 2002/03/21 07:13:47 japj Exp $

Detailed description:
This patch will (together with an update vgabios) add support for 
VBE Linear Frame Buffer modes.

The file patch.vbe-lfb-bios.tar.gz contains a LFB enabled vbebios.
It was build from the vgabios sources on 24 March 2002 with
#define VBE_HAVE_LFB uncommented in vbe.c

In order to test the LFB code, you need to replace the vgaromimage: 
line in .bochsrc to the extracted vbebios.bin.

The tar.gz file also contains a 'debug' build bios that shows lots
of information on the bochsout logfile.

Patch was created with:
  cvs diff -u
Apply patch to what version:
  cvs checked out on 24 March 2002, release version 1.4pre1
Instructions:
  To patch, go to main bochs directory.
  Type "patch -p0 < THIS_PATCH_FILE".
----------------------------------------------------------------------
*** iodev/vga.cc	16 Mar 2002 11:37:43 -0000	1.29
--- iodev/vga.cc	24 Mar 2002 10:30:06 -0000
@@ -2081,9 +2081,20 @@
 bx_vga_c::vbe_mem_read(Bit32u addr)
 {
   Bit32u offset;        
-  offset = addr - 0xA0000;
+  
+  if (addr >= VBE_DISPI_LFB_PHYSICAL_ADDRESS)
+  {
+    // LFB read
+    // FIXME: check for max VBE video memory size
+    offset = offset - VBE_DISPI_LFB_PHYSICAL_ADDRESS;
+  }
+  else
+  {
+    // banked mode read
+    offset = BX_VGA_THIS s.vbe_bank*65536 + addr - 0xA0000;
+  }
 
-  return (BX_VGA_THIS s.vbe_memory[BX_VGA_THIS s.vbe_bank*65536 + offset]);
+  return (BX_VGA_THIS s.vbe_memory[offset]);
 }
 
   void
@@ -2091,7 +2102,18 @@
 {
   Bit32u offset;        
   unsigned x_tileno, y_tileno;
-  offset = BX_VGA_THIS s.vbe_bank*65536 + (addr - 0xA0000);
+  
+  if (addr >= VBE_DISPI_LFB_PHYSICAL_ADDRESS)
+  {
+    // LFB write
+    // FIXME: check for max VBE video memory size
+    offset = offset - VBE_DISPI_LFB_PHYSICAL_ADDRESS;
+  }
+  else
+  {
+    // banked mode write
+    offset = BX_VGA_THIS s.vbe_bank*65536 + (addr - 0xA0000);
+  }
 
   // check for out of memory write
   if (offset < sizeof(BX_VGA_THIS s.vbe_memory))


*** iodev/vga.h	16 Mar 2002 10:22:57 -0000	1.10
--- iodev/vga.h	24 Mar 2002 10:30:11 -0000
@@ -52,6 +52,8 @@
 
   #define VBE_DISPI_DISABLED              0x00
   #define VBE_DISPI_ENABLED               0x01
+  #define VBE_DISPI_LFB_PHYSICAL_ADDRESS  0xE0000000
+  
 
 #define BX_MAX_XRES VBE_DISPI_MAX_XRES
 #define BX_MAX_YRES VBE_DISPI_MAX_YRES


*** memory/memory.cc	3 Oct 2001 13:10:38 -0000	1.9
--- memory/memory.cc	24 Mar 2002 10:30:16 -0000
@@ -224,6 +224,37 @@
   data_ptr = (Bit8u *) data + (len - 1);
 #endif
 
+
+#if BX_SUPPORT_VBE
+    // Check VBE LFB support
+    
+    if (a20addr >= VBE_DISPI_LFB_PHYSICAL_ADDRESS)
+    {
+      for (i = 0; i < len; i++) {
+        // FIXME: check for max VBE video memory size
+        
+        //if (a20addr < BX_MEM_THIS len) {
+          //vector[a20addr] = *data_ptr;
+          //BX_DBG_DIRTY_PAGE(a20addr >> 12);
+          //BX_DYN_DIRTY_PAGE(a20addr >> 12);
+          BX_VGA_MEM_WRITE(a20addr, *data_ptr);
+        //  }
+        
+        // otherwise ignore byte, since it overruns memory
+        addr++;
+        a20addr = A20ADDR(addr);
+#ifdef BX_LITTLE_ENDIAN
+        data_ptr++;
+#else // BX_BIG_ENDIAN
+        data_ptr--;
+#endif
+      }
+      return;
+    }
+    
+#endif    
+ 
+
 #if BX_SUPPORT_APIC
     bx_generic_apic_c *local_apic = &cpu->local_apic;
     bx_generic_apic_c *ioapic = bx_devices.ioapic;
@@ -422,6 +453,36 @@
 #else // BX_BIG_ENDIAN
     data_ptr = (Bit8u *) data + (len - 1);
 #endif
+
+#if BX_SUPPORT_VBE
+    // Check VBE LFB support
+    
+    if (a20addr >= VBE_DISPI_LFB_PHYSICAL_ADDRESS)
+    {
+      for (i = 0; i < len; i++) {
+        // FIXME: check for max VBE video memory size
+        
+        //if (a20addr < BX_MEM_THIS len) {
+          //vector[a20addr] = *data_ptr;
+          //BX_DBG_DIRTY_PAGE(a20addr >> 12);
+          //BX_DYN_DIRTY_PAGE(a20addr >> 12);
+          *data_ptr = BX_VGA_MEM_READ(a20addr);
+        //  }
+        
+        // otherwise ignore byte, since it overruns memory
+        addr++;
+        a20addr = A20ADDR(addr);
+#ifdef BX_LITTLE_ENDIAN
+        data_ptr++;
+#else // BX_BIG_ENDIAN
+        data_ptr--;
+#endif
+      }
+      return;
+    }
+    
+#endif    
+
 
 #if BX_SUPPORT_APIC
     bx_generic_apic_c *local_apic = &cpu->local_apic;