[tkreuzer] 48701: Update the GAS compatible fathelp.S file to reflect the latest changes to the original file (freeldr PE conversion). This version is tested and works.

Author: tkreuzer
Date: Sun Sep  5 16:03:08 2010
New Revision: 48701

URL: http://svn.reactos.org/svn/reactos?rev=48701&view=rev
Log:
Update the GAS compatible fathelp.S file to reflect the latest changes to the original file (freeldr PE conversion). This version is tested and works.

Modified:
    trunk/reactos/boot/freeldr/freeldr/arch/amd64/fathelp.S

Modified: trunk/reactos/boot/freeldr/freeldr/arch/amd64/fathelp.S
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/a...
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/amd64/fathelp.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/arch/amd64/fathelp.S [iso-8859-1] Sun Sep  5 16:03:08 2010
@@ -4,9 +4,12 @@

.intel_syntax noprefix

+//org 8000h
+
 .text

.code16
+

#define BootSectorStackTop		0x7bf2
 #define DataAreaStartHigh		0x2
@@ -38,6 +41,8 @@
 #define VolumeLabel				43
 #define FileSystem				54

+#define BootPartition			0x7dfd
+

// This code will be stored in the first 512 bytes
 // of freeldr.sys. The first 3 bytes will be a jmp
@@ -46,7 +51,6 @@
 //
 // This code is loaded at 0000:8000 so we have to
 // encode a jmp instruction to jump to 0000:8200
-//.org 0x8000

.global _mainCRTStartup	// For Mingw32 builds where the linker looks for this symbol
 _mainCRTStartup:
@@ -119,14 +123,14 @@
         jmp  LoadFile						// Load the next cluster (if any)

LoadFile_Done:
-        mov  dl, [bp+BootDrive]	// Load the boot drive into DL
-		mov  dh, BootPartition				// Load the boot partition into DH
-        push word ptr 0x0000
-        push word ptr 0x8000					// We will do a far return to 0000:8000h
-
-//        retf								// Transfer control to ROSLDR
-	.byte 0xcb // == retf
-
+        mov  dl,BYTE PTR [bp+BootDrive]		// Load the boot drive into DL
+		mov  dh,[BootPartition]				// Load the boot partition into DH
+
+		push 0						// push segment (0x0000)
+		mov bx, [0x8000 + 0xA8]		// load the RVA of the EntryPoint into eax
+		add bx, 0x8000				// RVA -> VA and skip 3 bytes (jump to fathelper code)
+		push bx						// push offset
+		retf						// Transfer control to FreeLoader

// Reads the entire FAT into memory at 7000:0000
 ReadFatIntoMemory:
@@ -225,15 +229,7 @@

-msgLoading:
-		.ascii "Loading FreeLoader..."
-		.byte 0x0d,0x0a,0
-
-//			times 510-($-$$) db 0	// Pad to 510 bytes
-.org 0x1fe
-			.word 0x0aa55				// BootSector signature
-
-
-// pseudo adresses
-//.org 0x7dfd
-BootPartition:
+msgLoading:	.asciz "Loading FreeLoader...\r\n"
+
+            .org 0x1fe				// Pad to 510 bytes
+			.word 0x0aa55			// BootSector signature