[ros-diffs] [tkreuzer] 52204: [FREELDR] Make freeldr/setupldr composed of a PE file and prepended raw 16bit code. The 16 bit code starts with the usual fathelp code. This brings back support for fragmented fat...

Author: tkreuzer
Date: Sun Jun 12 21:21:47 2011
New Revision: 52204

URL: http://svn.reactos.org/svn/reactos?rev=52204&view=rev
Log:
[FREELDR]
Make freeldr/setupldr composed of a PE file and prepended raw 16bit code. The 16 bit code
starts with the usual fathelp code. This brings back support for fragmented fat12/16
disks.
Later all 16 bit code is supposed to go into the raw binary chunk to be able to build
freeldr with MSVC.

Added:
    trunk/reactos/boot/freeldr/freeldr/arch/realmode/   (with props)
    trunk/reactos/boot/freeldr/freeldr/arch/realmode/amd64.S   (with props)
    trunk/reactos/boot/freeldr/freeldr/arch/realmode/fathelp.inc
    trunk/reactos/boot/freeldr/freeldr/arch/realmode/helpers.inc
    trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S   (with props)
Modified:
    trunk/reactos/boot/freeldr/bootsect/fat.S
    trunk/reactos/boot/freeldr/bootsect/fat32.S
    trunk/reactos/boot/freeldr/bootsect/isoboot.S
    trunk/reactos/boot/freeldr/freeldr/CMakeLists.txt
    trunk/reactos/boot/freeldr/freeldr/arch/i386/fathelp.S

Modified: trunk/reactos/boot/freeldr/bootsect/fat.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/bootsect/fat.…
==============================================================================
--- trunk/reactos/boot/freeldr/bootsect/fat.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/bootsect/fat.S [iso-8859-1] Sun Jun 12 21:21:47 2011
@@ -227,12 +227,7 @@
     // to the helper code. Skip the first three bytes
     // because they contain a jump instruction to skip
     // over the helper code in the FreeLoader image.
-    //jmp  0000:9003h
-    push 0						// push segment (0x0000)
-    mov bx, [HEX(8000) + HEX(0A8)]		// load the RVA of the EntryPoint into eax
-    add bx, HEX(8003)				// RVA -> VA and skip 3 bytes (jump to fathelper code)
-    push bx						// push offset
-    retf						// Transfer control to FreeLoader
+    ljmp16 0, HEX(8003)
 
 
 

Modified: trunk/reactos/boot/freeldr/bootsect/fat32.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/bootsect/fat3…
==============================================================================
--- trunk/reactos/boot/freeldr/bootsect/fat32.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/bootsect/fat32.S [iso-8859-1] Sun Jun 12 21:21:47 2011
@@ -420,11 +420,8 @@
     mov  dl, byte ptr BP_REL(BootDrive)              // Load boot drive into DL
     mov  dh, byte ptr ds:[BootPartition]           // Load boot partition into DH
 
-    push 0                                      // push segment (0x0000)
-    mov  eax, dword ptr ds:[HEX(8000) + HEX(0A8)]   // load the RVA of the EntryPoint
into eax
-    add  eax, HEX(8000)                          // RVA -> VA
-    push ax                                     // push offset
-    retf                                        // Transfer control to FreeLoader
+    /* Transfer execution to the bootloader */
+    ljmp16 0, HEX(8000)
 
 // Returns the FAT entry for a given cluster number
 // On entry EAX has cluster number

Modified: trunk/reactos/boot/freeldr/bootsect/isoboot.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/bootsect/isob…
==============================================================================
--- trunk/reactos/boot/freeldr/bootsect/isoboot.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/bootsect/isoboot.S [iso-8859-1] Sun Jun 12 21:21:47 2011
@@ -372,12 +372,9 @@
 
     mov dl, byte ptr ds:[DriveNo]            // dl = boot drive
     mov dh, 0                    // dh = boot partition
-    push 0                        // push segment (0x0000)
-    mov eax, dword ptr ds:[HEX(8000) + HEX(0A8)]    // load the RVA of the EntryPoint
into eax
-    add eax, HEX(8000)                // RVA -> VA
-    push ax                        // push offset
-    retf                        // Transfer control to ROSLDR
-
+
+    /* Transfer execution to the bootloader */
+    ljmp16 0, HEX(8000)
 
 //
 // searchdir:

Modified: trunk/reactos/boot/freeldr/freeldr/CMakeLists.txt
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/CMake…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/CMakeLists.txt [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/CMakeLists.txt [iso-8859-1] Sun Jun 12 21:21:47
2011
@@ -14,7 +14,6 @@
             arch/i386/realmode.S)
     else()
         list(APPEND FREELDR_STARTUP_SOURCE
-            arch/i386/fathelp.S
             arch/i386/arch.S)
     endif()
 elseif(ARCH MATCHES amd64)
@@ -23,7 +22,6 @@
             arch/amd64/stubs.S)
     else()
         list(APPEND FREELDR_STARTUP_SOURCE
-            arch/i386/fathelp.S
             arch/amd64/arch.S)
     endif()
 endif()
@@ -182,6 +180,11 @@
 add_library(freeldr_arch ${FREELDR_ARCH_SOURCE})
 add_dependencies(freeldr_arch bugcodes)
 
+CreateBootSectorTarget2(frldr16
+    ${CMAKE_CURRENT_SOURCE_DIR}/arch/realmode/i386.S
+    ${CMAKE_CURRENT_BINARY_DIR}/frldr16.bin
+    8000)
+
 list(APPEND FREELDR_SOURCE
     bootmgr.c
     ${FREELDR_STARTUP_SOURCE}
@@ -189,24 +192,23 @@
     ${FREELDR_BASE_SOURCE}
     )
 
-add_library(freeldr SHARED ${FREELDR_SOURCE})
+add_executable(freeldr_pe ${FREELDR_SOURCE})
 
 if(NOT MSVC)
-    set_target_properties(freeldr PROPERTIES LINK_FLAGS "-Wl,--strip-all
-Wl,--exclude-all-symbols -Wl,--file-alignment,0x1000
-Wl,-T,${CMAKE_CURRENT_SOURCE_DIR}/freeldr_i386.lnk" SUFFIX ".sys")
-set_image_base(freeldr 0x8000)
+    set_target_properties(freeldr_pe PROPERTIES LINK_FLAGS "-Wl,--strip-all
-Wl,--exclude-all-symbols -Wl,--file-alignment,0x1000
-Wl,-T,${CMAKE_CURRENT_SOURCE_DIR}/freeldr_i386.lnk")
 else()
-    set_target_properties(freeldr PROPERTIES LINK_FLAGS "/ignore:4078 /ignore:4254
/DRIVER /FIXED /ALIGN:0x400 /SECTION:.text,ERW /SECTION:.data,RW /MERGE:.text16=.text
/MERGE:.data=.text /MERGE:.rdata=.text /MERGE:.bss=.text /SUBSYSTEM:BOOT_APPLICATION"
SUFFIX ".sys")
-set_image_base(freeldr 0x10000)
-endif()
-
-set_subsystem(freeldr native)
-set_entrypoint(freeldr mainCRTStartup)
-
-if(ARCH MATCHES i386)
-    target_link_libraries(freeldr mini_hal)
-endif()
-
-target_link_libraries(freeldr
+    set_target_properties(freeldr_pe PROPERTIES LINK_FLAGS "/ignore:4078
/ignore:4254 /DRIVER /FIXED /ALIGN:0x400 /SECTION:.text,ERW /SECTION:.data,RW
/MERGE:.text16=.text /MERGE:.data=.text /MERGE:.rdata=.text /MERGE:.bss=.text
/SUBSYSTEM:BOOT_APPLICATION")
+endif()
+
+set_subsystem(freeldr_pe native)
+set_image_base(freeldr_pe 0x9000)
+set_entrypoint(freeldr_pe mainCRTStartup)
+
+if(ARCH MATCHES i386)
+    target_link_libraries(freeldr_pe mini_hal)
+endif()
+
+target_link_libraries(freeldr_pe
     freeldr_arch
     cportlib
     rossym
@@ -214,10 +216,17 @@
     rtl
     libcntpr)
 
-add_pch(freeldr include/freeldr.h)
-add_dependencies(freeldr asm)
-
-add_cd_file(TARGET freeldr DESTINATION loader NO_CAB FOR all)
+add_pch(freeldr_pe include/freeldr.h)
+add_dependencies(freeldr_pe asm)
+
+concatenate_files(
+    ${CMAKE_CURRENT_BINARY_DIR}/frldr16.bin
+    ${CMAKE_CURRENT_BINARY_DIR}/freeldr_pe.exe
+    ${CMAKE_CURRENT_BINARY_DIR}/freeldr.sys)
+
+add_custom_target(freeldr ALL DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/freeldr.sys)
+
+add_cd_file(FILE ${CMAKE_CURRENT_BINARY_DIR}/freeldr.sys DESTINATION loader NO_CAB FOR
all)
 
 list(APPEND SETUPLDR_MAIN_SOURCE
     bootmgr.c
@@ -238,23 +247,23 @@
     ${FREELDR_BASE_SOURCE}
     ${SETUPLDR_MAIN_SOURCE})
 
-add_library(setupldr SHARED ${SETUPLDR_SOURCE})
+add_executable(setupldr_pe ${SETUPLDR_SOURCE})
 
 if(NOT MSVC)
-    set_target_properties(setupldr PROPERTIES LINK_FLAGS "-Wl,--strip-all
-Wl,--exclude-all-symbols -Wl,--file-alignment,0x1000
-Wl,-T,${CMAKE_CURRENT_SOURCE_DIR}/freeldr_i386.lnk" SUFFIX ".sys"
COMPILE_DEFINITIONS "FREELDR_REACTOS_SETUP")
-set_image_base(setupldr 0x8000)
+    set_target_properties(setupldr_pe PROPERTIES LINK_FLAGS "-Wl,--strip-all
-Wl,--exclude-all-symbols -Wl,--file-alignment,0x1000
-Wl,-T,${CMAKE_CURRENT_SOURCE_DIR}/freeldr_i386.lnk" COMPILE_DEFINITIONS
"FREELDR_REACTOS_SETUP")
 else()
-    set_target_properties(setupldr PROPERTIES LINK_FLAGS "/DRIVER
/SECTION:.text,ERWP,ALIGN=0x1000" SUFFIX ".sys" COMPILE_DEFINITIONS
"FREELDR_REACTOS_SETUP")
-endif()
-
-set_subsystem(setupldr native)
-set_entrypoint(setupldr mainCRTStartup)
-
-if(ARCH MATCHES i386)
-    target_link_libraries(setupldr mini_hal)
-endif()
-
-target_link_libraries(setupldr
+    set_target_properties(setupldr_pe PROPERTIES LINK_FLAGS "/DRIVER
/SECTION:.text,ERWP,ALIGN=0x1000" COMPILE_DEFINITIONS
"FREELDR_REACTOS_SETUP")
+endif()
+
+set_subsystem(setupldr_pe native)
+set_image_base(setupldr_pe 0x9000)
+set_entrypoint(setupldr_pe mainCRTStartup)
+
+if(ARCH MATCHES i386)
+    target_link_libraries(setupldr_pe mini_hal)
+endif()
+
+target_link_libraries(setupldr_pe
     freeldr_arch
     cportlib
     rossym
@@ -262,7 +271,14 @@
     rtl
     libcntpr)
 
-add_dependencies(setupldr asm)
-
-add_cd_file(TARGET setupldr DESTINATION loader NO_CAB FOR all)
-
+add_dependencies(setupldr_pe asm)
+
+concatenate_files(
+    ${CMAKE_CURRENT_BINARY_DIR}/frldr16.bin
+    ${CMAKE_CURRENT_BINARY_DIR}/setupldr_pe.exe
+    ${CMAKE_CURRENT_BINARY_DIR}/setupldr.sys)
+
+add_custom_target(setupldr ALL DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/setupldr.sys)
+
+add_cd_file(FILE ${CMAKE_CURRENT_BINARY_DIR}/setupldr.sys DESTINATION loader NO_CAB FOR
all)
+

Modified: trunk/reactos/boot/freeldr/freeldr/arch/i386/fathelp.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/i386/fathelp.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/arch/i386/fathelp.S [iso-8859-1] Sun Jun 12
21:21:47 2011
@@ -56,6 +56,7 @@
 _mainCRTStartup:
 PUBLIC start
 start:
+#if 0
         .byte	HEX(e9)
 		.byte	HEX(fd)
 		.byte	HEX(01)
@@ -134,7 +135,7 @@
 
 // Reads the entire FAT into memory at 7000:0000
 ReadFatIntoMemory:
-        mov   ax, [bp+HiddenSectors] 
+        mov   ax, [bp+HiddenSectors]
         mov   dx, [bp+HiddenSectors+2]
 		add   ax, [bp+ReservedSectors]
 		adc   dx, 0
@@ -233,6 +234,7 @@
 
             .org HEX(1fe)				// Pad to 510 bytes
 			.word HEX(0aa55)			// BootSector signature
+#endif
 
 .endcode16
 

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/
------------------------------------------------------------------------------
--- bugtraq:logregex (added)
+++ bugtraq:logregex Sun Jun 12 21:21:47 2011
@@ -1,0 +1,2 @@
+([Ii]ssue|[Bb]ug)s? #?(\d+)(,? ?#?(\d+))*(,? ?(and |or )?#?(\d+))?
+(\d+)

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/
------------------------------------------------------------------------------
    bugtraq:message = See issue #%BUGID% for more details.

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/
------------------------------------------------------------------------------
    bugtraq:url = http://www.reactos.org/bugzilla/show_bug.cgi?id=%BUGID%

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/
------------------------------------------------------------------------------
    tsvn:logminsize = 10

Added: trunk/reactos/boot/freeldr/freeldr/arch/realmode/amd64.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/amd64.S (added)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/amd64.S [iso-8859-1] Sun Jun 12
21:21:47 2011
@@ -1,0 +1,225 @@
+
+#include <asm.inc>
+#include <arch/pc/x86common.h>
+
+#define IMAGE_DOS_HEADER_e_lfanew 36
+#define IMAGE_FILE_HEADER_SIZE 20
+#define IMAGE_OPTIONAL_HEADER_AddressOfEntryPoint 16
+
+
+.code16
+
+/* fat helper code */
+#include "fathelp.inc"
+
+.org 512
+RealEntryPoint:
+
+	cli
+
+	/* Setup real mode segment registers */
+	xor ax, ax
+	mov	ds, ax
+	mov es, ax
+	mov fs, ax
+	mov	gs, ax
+	mov ss, ax
+
+	/* checkPoint Charlie - where it all began... */
+	mov si, offset CheckPoint0
+	call writestr
+
+	/* Setup a real mode stack */
+	mov	sp, stack16
+
+	/* Zero BootDrive and BootPartition */
+	xor eax, eax
+	mov BootDrive, eax
+	mov BootPartition, eax
+
+	/* Store the boot drive */
+	mov BootDrive, dl
+
+	/* Store the boot partition */
+	mov BootPartition, dh
+
+	/* Load the GDT */
+	lgdt gdtptr
+	/* Load the IDT */
+//	lidt idtptr
+
+	call x86_16_EnableA20
+
+	/* checkPoint Charlie - where it all began... */
+	mov si, offset CheckPoint1
+	call writestr
+
+	call x86_16_BuildPageTables
+
+	/* checkPoint Charlie - where it all began... */
+	mov si, offset CheckPoint2
+	call writestr
+
+	/* Check if CPU supports CPUID */
+	pushfd
+	pop eax
+	mov ebx, eax
+	xor eax, HEX(00200000)
+	push eax
+	popfd
+	pushfd
+	pop eax
+	cmp eax,ebx
+	jz no_cpuid_support_detected
+
+	/* CPUID support detected - getting the PAE/PGE */
+
+	mov eax,1 // Fn0000_0001 - PAE in EDX[6]
+	cpuid
+	xor eax,eax
+	and edx, HEX(00a0)
+	test edx,edx // are PAE and PGE bits set?
+	jz no_x64_support_detected
+
+	/* PAE and PGE are here */
+
+	xor edx, edx
+	mov eax, HEX(80000001)
+	cpuid
+	and edx, HEX(20000000)
+	test edx,edx
+	jz no_x64_support_detected
+
+	/* X64 Processor */
+
+	/* checkPoint Charlie - where it all began... */
+	mov si, offset CheckPoint3
+	call writestr
+
+    /* Get address of optional header */
+    mov eax, dword ptr ds:[FREELDR_PE_BASE + IMAGE_DOS_HEADER_e_lfanew]
+    add eax, FREELDR_PE_BASE + 4 + IMAGE_FILE_HEADER_SIZE
+
+    /* Get address of entry point */
+    mov eax, dword ptr ds:[eax + IMAGE_OPTIONAL_HEADER_AddressOfEntryPoint]
+
+    /* Store the address in the callback return variable */
+    mov dword ptr ds:[CallbackReturnAddress], eax
+
+switch64:
+    mov
+	jmp x86_16_ReturnToLong
+
+
+no_x64_support_detected:
+	mov  si, offset NotAnX64Processor	// Loading message
+	call writestr
+	jmp fail
+
+no_cpuid_support_detected:
+	mov  si, offset NoCPUIDSupport	// Loading message
+   	call writestr
+
+fail:
+	jmp fail
+	nop
+	nop
+
+/*
+ * We define 512 2MB pages at the start of memory, so we can access the first
+ * 1 GB as if paging was disabled
+ */
+x86_16_BuildPageTables:
+	pusha
+	push es
+
+	/* Get segment of pml4 */
+	mov eax, offset pml4_startup
+	shr eax, 4
+	mov es, ax
+	cld
+	xor di, di
+
+	/* One entry in the PML4 pointing to PDP */
+	mov eax, offset pdp_startup
+	or eax, HEX(00f)
+	stosd
+	/* clear rest */
+	xor eax, eax
+	mov cx, HEX(03ff)
+	rep stosd
+
+	/* One entry in the PDP pointing to PD */
+	mov eax, offset pd_startup
+	or eax, HEX(00f)
+	stosd
+	/* clear rest */
+	xor eax, eax
+	mov ecx, HEX(03ff)
+	rep stosd
+
+	/* 512 entries in the PD defining a 2MB page each */
+	mov ecx, 512
+	mov eax, HEX(008f)
+
+Bpt2:
+	mov es: [di], eax
+	mov dword ptr es: [di + 4], 0
+	add eax, 512 << 12 // add 512 4k pages
+	add di, 8
+
+	/* Loop it */
+	dec cx
+	jnz Bpt2
+
+	/* Return */
+	pop es
+	popa
+	ret
+
+
+
+
+
+x86_16_ReturnToLong:
+
+	cli
+
+	xor	ax,ax
+	mov	ds,ax
+	mov	es,ax
+	mov	fs,ax
+	mov	gs,ax
+	mov	ss,ax
+
+	/* Get the return address off the stack */
+	pop	word ptr code64ret
+
+	/* Save 16-bit stack pointer */
+	mov	stack16, sp
+
+	mov eax, 0x00a0			// Set PAE and PGE: 10100000b
+	mov cr4, eax
+
+	mov edx, offset pml4_startup // Point cr3 at PML4
+	mov cr3, edx
+
+	mov ecx, HEX(0C0000080)		// Specify EFER MSR
+
+	rdmsr					// Enable long mode
+	or eax, HEX(00000100)
+	wrmsr
+
+	mov ebx, cr0			// Activate long mode
+	or ebx, HEX(080000001)		// by enabling paging and protection simultaneously
+	mov cr0, ebx			// skipping protected mode entirely
+
+	//jmp LMODE_CS:offset LongCat	//Load CS with 64 bit segment and flush the instruction
cache
+    // Do a long jmp to the CallbackReturn address
+
+
+#include "helpers.inc"
+
+.endcode16
+
+END

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/amd64.S
------------------------------------------------------------------------------
    svn:eol-style = native

Added: trunk/reactos/boot/freeldr/freeldr/arch/realmode/fathelp.inc
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/fathelp.inc (added)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/fathelp.inc [iso-8859-1] Sun Jun 12
21:21:47 2011
@@ -1,0 +1,225 @@
+// fathelp.S
+// FAT12/16 Boot Sector Helper Code
+// Copyright (c) 1998, 2001, 2002, 2003 Brian Palmer
+
+//#include <asm.inc>
+
+//org 8000h
+
+//.text
+
+#define BootSectorStackTop		HEX(7bf2)
+#define DataAreaStartHigh		2
+#define DataAreaStartLow		4
+#define BiosCHSDriveSizeHigh	6
+#define BiosCHSDriveSizeLow		8
+#define BiosCHSDriveSize		8
+#define ReadSectorsOffset		10
+#define ReadClusterOffset		12
+#define PutCharsOffset			14
+
+#define OEMName					3
+#define BytesPerSector			11
+#define SectsPerCluster			13
+#define ReservedSectors			14
+#define NumberOfFats			16
+#define MaxRootEntries			17
+#define TotalSectors			19
+#define MediaDescriptor			21
+#define SectorsPerFat			22
+#define SectorsPerTrack			24
+#define NumberOfHeads			26
+#define HiddenSectors			28
+#define TotalSectorsBig			32
+#define BootDrive				36
+#define Reserved				37
+#define ExtendSig				38
+#define SerialNumber			39
+#define VolumeLabel				43
+#define FileSystem				54
+
+#define BootPartition			HEX(7dfd)
+
+
+// This code will be stored in the first 512 bytes
+// of freeldr.sys. The first 3 bytes will be a jmp
+// instruction to skip past the FAT helper code
+// that is stored in the rest of the 512 bytes.
+//
+
+PUBLIC start
+start:
+    // This code is loaded at 0000:8000 so we have to
+    // encode a jmp instruction to jump to 0000:8200
+    .byte HEX(e9), HEX(fd), HEX(01)
+
+// Now starts the extra boot code that we will store
+// in the first 512 bytes of freeldr.sys. This code
+// allows the FAT12/16 bootsector to navigate the
+// FAT table so that we can still load freeldr.sys
+// even if it is fragmented.
+
+
+FatHelperEntryPoint:
+    /* First save AX - the start cluster of freeldr.sys */
+    push ax
+
+    /* Display "Loading FreeLoader..." message */
+    mov si, offset msgLoading
+    call word ptr [bp-PutCharsOffset]
+
+    call ReadFatIntoMemory
+
+    /* Restore AX (start cluster) */
+    pop ax
+
+    // AX has start cluster of freeldr.sys
+    mov  bx, HEX(800)
+    mov  es,bx
+
+LoadFile:
+    push ax
+    call IsFat12
+    pop  ax
+    jnc  LoadFile2
+    cmp  ax, HEX(0ff8)		    // Check to see if this is the last cluster in the chain
+    jmp  LoadFile3
+
+LoadFile2:
+    cmp  ax, HEX(0fff8)
+LoadFile3:
+    jae	 LoadFile_Done		// If so continue, if not then read then next one
+    push ax
+    xor  bx,bx              // Load ROSLDR starting at 0000:8000h
+    push es
+    call word ptr [bp-ReadClusterOffset]
+    pop  es
+
+    xor  bx,bx
+    mov  bl, [bp+SectsPerCluster]
+    shl  bx,5							// BX = BX * 512 / 16
+    mov  ax,es							// Increment the load address by
+    add  ax,bx							// The size of a cluster
+    mov  es,ax
+
+    call IsFat12
+    pop  ax
+    push es
+    jnc  LoadFile4
+    call GetFatEntry12					// Get the next entry
+    jmp  LoadFile5
+LoadFile4:
+    call GetFatEntry16
+LoadFile5:
+    pop  es
+
+    jmp  LoadFile						// Load the next cluster (if any)
+
+LoadFile_Done:
+    mov  dl, byte ptr [bp+BootDrive]		// Load the boot drive into DL
+    mov  dh, byte ptr ds:[BootPartition]	// Load the boot partition into DH
+
+    /* continue where other bootsectors start */
+    jmp start
+
+
+// Reads the entire FAT into memory at 7000:0000
+ReadFatIntoMemory:
+    mov ax, [bp+HiddenSectors]
+    mov dx, [bp+HiddenSectors+2]
+    add ax, [bp+ReservedSectors]
+    adc dx, 0
+    mov cx, [bp+SectorsPerFat]
+    mov bx, HEX(7000)
+    mov es,bx
+    xor bx,bx
+    call word ptr [bp-ReadSectorsOffset]
+    ret
+
+
+// Returns the FAT entry for a given cluster number for 16-bit FAT
+// On entry AX has cluster number
+// On return AX has FAT entry for that cluster
+GetFatEntry16:
+    mov cx,2						// AX = AX * 2 (since FAT16 entries are 2 bytes)
+    mul cx
+    shl dx,12
+
+    mov bx, HEX(7000)
+    add bx,dx
+    mov es,bx
+    mov bx,ax						// Restore FAT entry offset
+    mov ax, es:[bx]	    	// Get FAT entry
+
+    ret
+
+
+// Returns the FAT entry for a given cluster number for 12-bit FAT
+// On entry AX has cluster number
+// On return AX has FAT entry for that cluster
+GetFatEntry12:
+    push  ax
+    mov   cx,ax
+    shr   ax,1
+    add   ax,cx						// AX = AX * 1.5 (AX = AX + (AX / 2)) (since FAT12 entries are 12
bits)
+
+    mov   bx, HEX(7000)
+    mov   es,bx
+    mov   bx,ax						// Put FAT entry offset into BX
+    mov   ax, es:[bx]	    	// Get FAT entry
+    pop   cx						// Get cluster number from stack
+    and   cx,1
+    jz    UseLow12Bits
+    and   ax, HEX(0fff0)
+    shr   ax,4
+    jmp   GetFatEntry12_Done
+
+UseLow12Bits:
+    and   ax, HEX(0fff)
+
+GetFatEntry12_Done:
+
+    ret
+
+
+// Returns CF = 1 if this is a FAT12 file system
+// Otherwise CF = 0 for FAT16
+IsFat12:
+
+    mov   ebx, dword ptr [bp-DataAreaStartLow]
+    // EBX now has the number of the starting sector of the data area
+    // starting from the beginning of the disk, so subtrace hidden sectors
+    sub   ebx, dword ptr [bp+HiddenSectors]
+
+
+    xor   eax,eax
+    mov   ax, word ptr [bp+TotalSectors]
+    cmp   ax, 0
+    jnz   IsFat12_2
+    mov   eax, dword ptr [bp+TotalSectorsBig]
+
+    // EAX now contains the number of sectors on the volume
+
+IsFat12_2:
+    sub   eax,ebx				// Subtract data area start sector
+    xor   edx,edx				// from total sectors of volume
+
+    // EDX:EAX now contains the number of data sectors on the volume
+    movzx ebx, byte ptr [bp+SectsPerCluster]
+    div   ebx
+    // EAX now has the number of clusters on the volume
+    stc
+    cmp   eax,4085
+    jb    IsFat12_Done
+    clc
+
+IsFat12_Done:
+    ret
+
+
+msgLoading:	.asciz "Loading FreeLoader...\r\n"
+
+    .org 510				// Pad to 510 bytes
+    .word HEX(0aa55)		// BootSector signature
+
+END

Added: trunk/reactos/boot/freeldr/freeldr/arch/realmode/helpers.inc
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/helpers.inc (added)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/helpers.inc [iso-8859-1] Sun Jun 12
21:21:47 2011
@@ -1,0 +1,104 @@
+
+Empty8042:
+    .word 0x00eb,0x00eb		// jmp $+2, jmp $+2
+    in al, 0x64
+    cmp al, 0xff				// legacy-free machine without keyboard
+    jz empty_8042_ret			// controllers on Intel Macs read back 0xFF
+    test al, 0x02
+    jnz x86_16_Empty8042
+empty_8042_ret:
+	ret
+
+EnableA20:
+    pusha
+    call x86_16_Empty8042
+    mov al, 0xD1				// command write
+    out 0x64, al
+    call x86_16_Empty8042
+    mov al, 0xDF				// A20 on
+    out 0x60, al
+    call x86_16_Empty8042
+    popa
+    ret
+
+/*
+ * writestr
+ * si = pointer to zero terminated string
+ */
+writestr:
+	pushfd
+	pushad
+writestr_top:
+	lodsb
+	and	al, al
+	jz	writestr_end
+	call	writechr
+	jmp	short writestr_top
+writestr_end:
+	popad
+	popfd
+	ret
+
+/*
+ * writechr
+ * al = character to output
+ */
+writechr:
+	pushf
+	pusha
+	mov	ah, 0x0E
+	xor	bx, bx
+	int	0x10
+	popa
+	popf
+	ret
+
+//
+// writehex[248]: Write a hex number in (AL, AX, EAX) to the console
+//
+writehex2:
+    pushfd
+    pushad
+    shl    eax, 24
+    mov cx, 2
+    jmp    short writehex_common
+writehex4:
+    pushfd
+    pushad
+    shl    eax, 16
+    mov cx, 4
+    jmp    short writehex_common
+writehex8:
+    pushfd
+    pushad
+    mov cx, 8
+writehex_common:
+.loop:
+    rol    eax, 4
+    push    eax
+    and    al, HEX(0F)
+    cmp al, 10
+    jae    .high
+.low:
+    add    al, '0'
+    jmp    short .ischar
+.high:
+    add    al, 'A'-10
+.ischar:
+    call writechr
+    pop    eax
+    loop    .loop
+    popad
+    popfd
+    ret
+
+SoftReboot:
+	mov ax, HEX(40)
+	mov ds, ax
+	mov si, HEX(72)
+
+	/* Set the word at location 40:72 to 1234h */
+	mov word ptr [si], HEX(1234)
+
+	/* and jump to location FFFF:0 in ROM */
+	ljmp16	HEX(0FFFF), HEX(0000)

Added: trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/…
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S (added)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S [iso-8859-1] Sun Jun 12
21:21:47 2011
@@ -1,0 +1,32 @@
+
+#include <asm.inc>
+#include "../../include/arch/pc/x86common.h"
+
+#define IMAGE_DOS_HEADER_e_lfanew 60
+#define IMAGE_FILE_HEADER_SIZE 20
+#define IMAGE_OPTIONAL_HEADER_AddressOfEntryPoint 16
+
+.code16
+
+/* fat helper code */
+#include "fathelp.inc"
+
+.org 512
+RealEntryPoint:
+
+    /* Get address of optional header */
+    mov eax, dword ptr ds:[FREELDR_PE_BASE + IMAGE_DOS_HEADER_e_lfanew]
+    add eax, FREELDR_PE_BASE + 4 + IMAGE_FILE_HEADER_SIZE
+
+    /* Jump to address of entry point */
+    mov eax, dword ptr ds:[eax + IMAGE_OPTIONAL_HEADER_AddressOfEntryPoint]
+    add eax, FREELDR_PE_BASE
+    jmp ax
+
+
+#include "helpers.inc"
+
+.org (FREELDR_PE_BASE - FREELDR_BASE)
+.endcode16
+
+END

Propchange: trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S
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