Re: [ros-dev] [ros-diffs] [akhaldi] 48687: [FREELDR] - Convert fat12/16 boot sector helper code to gas syntax. Brought to you by the Arty. [CMAKE] - Add freeldr and setupldr to build.

[Alex Ionescu]

This is retarded, GAS supports Intel syntax. Why did this require
rewriting everything in AT&T syntax and introducing bugs? And what's
up with calling AT&T syntax "GAS" Syntax.

I wonder what Brian would say....

It's funny how this project gets rid of old developers, gets new
developers, and has them make the same mistakes/idiotic things the old
developers left for in the first place...

Good job!

Best regards,
Alex Ionescu

On Thu, Sep 2, 2010 at 10:39 AM,  [e-mail] wrote:
> Author: akhaldi
> Date: Thu Sep  2 17:39:45 2010
> New Revision: 48687
>
> URL: http://svn.reactos.org/svn/reactos?rev=48687&view=rev
> Log:
> [FREELDR]
> Convert fat12/16 boot sector helper code to gas syntax. Brought to you by the Arty.
>
> [CMAKE]
> Add freeldr and setupldr to build.
>
> Added:
>    branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.S
>      - copied, changed from r48568, branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm
> Removed:
>    branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm
> Modified:
>    branches/cmake-bringup/boot/CMakeLists.txt
>
> Modified: branches/cmake-bringup/boot/CMakeLists.txt
> URL: http://svn.reactos.org/svn/reactos/branches/cmake-bringup/boot/CMakeLists.tx...
> ==============================================================================
> --- branches/cmake-bringup/boot/CMakeLists.txt [iso-8859-1] (original)
> +++ branches/cmake-bringup/boot/CMakeLists.txt [iso-8859-1] Thu Sep  2 17:39:45 2010
> @@ -5,3 +5,203 @@
>  CreateBootSectorTarget(fat ${CMAKE_CURRENT_SOURCE_DIR}/freeldr/bootsect/fat.asm ${CMAKE_CURRENT_BINARY_DIR}/freeldr/bootsect/fat.bin)
>  CreateBootSectorTarget(isoboot ${CMAKE_CURRENT_SOURCE_DIR}/freeldr/bootsect/isoboot.asm ${CMAKE_CURRENT_BINARY_DIR}/freeldr/bootsect/isoboot.bin)
>  CreateBootSectorTarget(isobtrt ${CMAKE_CURRENT_SOURCE_DIR}/freeldr/bootsect/isobtrt.asm ${CMAKE_CURRENT_BINARY_DIR}/freeldr/bootsect/isobtrt.bin)
>
> +include_directories(BEFORE freeldr/freeldr/include)
> +include_directories(${REACTOS_SOURCE_DIR}/ntoskrnl/include)
>
> +if(ARCH MATCHES i386)
> +list(APPEND FREELDR_STARTUP_SOURCE
> freeldr/freeldr/arch/i386/fathelp.S
> freeldr/freeldr/arch/i386/arch.S)
>
> +elseif(ARCH MATCHES amd64)
> +list(APPEND FREELDR_STARTUP_SOURCE
> freeldr/freeldr/arch/amd64/fathelp.S
> freeldr/freeldr/arch/amd64/arch.S)
>
> +endif(ARCH MATCHES i386)
>
> +if(ARCH MATCHES i386)
> +list(APPEND FREELDR_BASE64K_SOURCE
> freeldr/freeldr/arch/i386/boot.S
> freeldr/freeldr/arch/i386/drvmap.S
> freeldr/freeldr/arch/i386/i386cpu.S
> freeldr/freeldr/arch/i386/i386idt.S
> freeldr/freeldr/arch/i386/i386pnp.S
> freeldr/freeldr/arch/i386/i386trap.S
> freeldr/freeldr/arch/i386/int386.S
> freeldr/freeldr/arch/i386/linux.S
> freeldr/freeldr/arch/i386/mb.S)
>
> +elseif(ARCH MATCHES amd64)
> +list(APPEND FREELDR_BASE64K_SOURCE
> freeldr/freeldr/arch/amd64/drvmap.S
> freeldr/freeldr/arch/amd64/i386cpu.S
> freeldr/freeldr/arch/amd64/i386idt.S
> freeldr/freeldr/arch/amd64/i386trap.S
> freeldr/freeldr/arch/amd64/mb.S)
>
> +endif(ARCH MATCHES i386)
>
> +set_source_files_properties(${FREELDR_BASE64K_SOURCE} PROPERTIES COMPILE_DEFINITIONS "_NTHAL_")
>
> +include_directories(${REACTOS_SOURCE_DIR}/lib/cmlib)
>
> +list(APPEND FREELDR_BASE_SOURCE
> freeldr/freeldr/arcemul/mm.c
> freeldr/freeldr/arcemul/time.c
> freeldr/freeldr/cache/blocklist.c
> freeldr/freeldr/cache/cache.c
> freeldr/freeldr/comm/rs232.c
> freeldr/freeldr/disk/disk.c
> freeldr/freeldr/disk/partition.c
> freeldr/freeldr/disk/ramdisk.c
> freeldr/freeldr/fs/ext2.c
> freeldr/freeldr/fs/fat.c
> freeldr/freeldr/fs/fs.c
> freeldr/freeldr/fs/iso.c
> freeldr/freeldr/fs/ntfs.c
> freeldr/freeldr/inifile/ini_init.c
> freeldr/freeldr/inifile/inifile.c
> freeldr/freeldr/inifile/parse.c
> freeldr/freeldr/mm/meminit.c
> freeldr/freeldr/mm/mm.c
> freeldr/freeldr/reactos/registry.c
> freeldr/freeldr/reactos/arcname.c
> freeldr/freeldr/reactos/archwsup.c
> freeldr/freeldr/reactos/binhive.c
> freeldr/freeldr/reactos/reactos.c
> freeldr/freeldr/reactos/imageldr.c
> freeldr/freeldr/rtl/bget.c
> freeldr/freeldr/rtl/libsupp.c
> freeldr/freeldr/ui/directui.c
> freeldr/freeldr/ui/gui.c
> freeldr/freeldr/ui/minitui.c
> freeldr/freeldr/ui/noui.c
> freeldr/freeldr/ui/tui.c
> freeldr/freeldr/ui/tuimenu.c
> freeldr/freeldr/ui/ui.c
> freeldr/freeldr/video/fade.c
> freeldr/freeldr/video/palette.c
> freeldr/freeldr/video/video.c
> freeldr/freeldr/windows/conversion.c
> freeldr/freeldr/windows/peloader.c
> freeldr/freeldr/windows/winldr.c
> freeldr/freeldr/windows/wlmemory.c
> freeldr/freeldr/windows/wlregistry.c
> freeldr/freeldr/freeldr.c
> freeldr/freeldr/debug.c
> freeldr/freeldr/version.c
> freeldr/freeldr/cmdline.c
> freeldr/freeldr/machine.c
> freeldr/freeldr/options.c
> freeldr/freeldr/linuxboot.c
> freeldr/freeldr/oslist.c)
>
> +if(ARCH MATCHES i386)
> +list(APPEND FREELDR_BASE_SOURCE freeldr/freeldr/disk/scsiport.c)
> +endif(ARCH MATCHES i386)
>
> +set_source_files_properties(${FREELDR_BASE_SOURCE} PROPERTIES COMPILE_DEFINITIONS "_NTHAL_;_BLDR_;_NTSYSTEM_")
>
> +include_directories(${REACTOS_SOURCE_DIR}/include/reactos/libs)
> +include_directories(${REACTOS_SOURCE_DIR}/include/reactos/elf)
>
> +if(ARCH MATCHES i386)
> +list(APPEND FREELDR_ARCH_SOURCE
> freeldr/freeldr/arch/i386/_alloca.S
> freeldr/freeldr/arch/i386/archmach.c
> freeldr/freeldr/arch/i386/custom.c
> freeldr/freeldr/arch/i386/drivemap.c
> freeldr/freeldr/arch/i386/halstub.c
> freeldr/freeldr/arch/i386/hardware.c
> freeldr/freeldr/arch/i386/hwacpi.c
> freeldr/freeldr/arch/i386/hwapm.c
> freeldr/freeldr/arch/i386/hwpci.c
> freeldr/freeldr/arch/i386/i386disk.c
> freeldr/freeldr/arch/i386/i386rtl.c
> freeldr/freeldr/arch/i386/i386vid.c
> freeldr/freeldr/arch/i386/loader.c
> freeldr/freeldr/arch/i386/machpc.c
> freeldr/freeldr/arch/i386/miscboot.c
> freeldr/freeldr/arch/i386/ntoskrnl.c
> freeldr/freeldr/arch/i386/pccons.c
> freeldr/freeldr/arch/i386/pcdisk.c
> freeldr/freeldr/arch/i386/pcmem.c
> freeldr/freeldr/arch/i386/pcrtc.c
> freeldr/freeldr/arch/i386/pcvideo.c
> freeldr/freeldr/arch/i386/machxbox.c
> freeldr/freeldr/arch/i386/xboxcons.c
> freeldr/freeldr/arch/i386/xboxdisk.c
> freeldr/freeldr/arch/i386/xboxfont.c
> freeldr/freeldr/arch/i386/xboxhw.c
> freeldr/freeldr/arch/i386/xboxi2c.c
> freeldr/freeldr/arch/i386/xboxmem.c
> freeldr/freeldr/arch/i386/xboxrtc.c
> freeldr/freeldr/arch/i386/xboxvideo.c
> freeldr/freeldr/windows/i386/ntsetup.c
> freeldr/freeldr/windows/i386/wlmemory.c)
>
> +else()
> +#TBD
> +endif(ARCH MATCHES i386)
>
> +set_source_files_properties(${FREELDR_ARCH_SOURCE} PROPERTIES COMPILE_DEFINITIONS "_NTHAL_;_BLDR_;_NTSYSTEM_")
>
> +list(APPEND SETUPLDR_MAIN_SOURCE
> freeldr/freeldr/bootmgr.c
> freeldr/freeldr/inffile/inffile.c
> freeldr/freeldr/reactos/setupldr.c)
>
> +if(ARCH MATCHES i386)
> +list(APPEND SETUPLDR_MAIN_SOURCE freeldr/freeldr/windows/setupldr2.c)
> +elseif(ARCH MATCHES amd64)
> +list(APPEND SETUPLDR_MAIN_SOURCE freeldr/freeldr/windows/setupldr2.c)
> +endif(ARCH MATCHES i386)
>
> +set_source_files_properties(${SETUPLDR_MAIN_SOURCE} PROPERTIES COMPILE_DEFINITIONS "_NTHAL_;FREELDR_REACTOS_SETUP" COMPILE_FLAGS "-ffreestanding -fno-builtin -fno-inline -fno-zero-initialized-in-bss")
>
> +set(CMAKE_C_CREATE_SHARED_LIBRARY "<CMAKE_C_COMPILER> <CMAKE_SHARED_LIBRARY_C_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
>
> +list(APPEND FREELDR_SOURCE
> freeldr/freeldr/bootmgr.c
> ${FREELDR_STARTUP_SOURCE}
> ${FREELDR_BASE64K_SOURCE}
> ${FREELDR_BASE_SOURCE}
> ${FREELDR_ARCH_SOURCE})
>
> +add_library(freeldr SHARED
> ${CMAKE_CURRENT_BINARY_DIR}/freeldr_freeldr.h.gch
> ${FREELDR_SOURCE})
>
> +set_target_properties(freeldr PROPERTIES LINK_FLAGS "-Wl,--strip-all -Wl,-entry,_mainCRTStartup -Wl,--image-base,0x8000 -Wl,--exclude-all-symbols -Wl,--subsystem,native" SUFFIX ".sys")
>
> +if(ARCH MATCHES i386)
> +target_link_libraries(freeldr mini_hal)
> +endif(ARCH MATCHES i386)
>
> +target_link_libraries(freeldr
> rossym
> cmlib
> rtl
> libcntpr)
>
> +add_pch(freeldr ${CMAKE_CURRENT_SOURCE_DIR}/freeldr/freeldr/include/freeldr.h ${FREELDR_SOURCE})
>
> +list(APPEND SETUPLDR_SOURCE
> ${FREELDR_STARTUP_SOURCE}
> ${FREELDR_BASE64K_SOURCE}
> ${FREELDR_BASE_SOURCE}
> ${FREELDR_ARCH_SOURCE}
> ${SETUPLDR_MAIN_SOURCE})
>
> +add_library(setupldr SHARED
> ${CMAKE_CURRENT_BINARY_DIR}/freeldr_freeldr.h.gch
> ${SETUPLDR_SOURCE})
>
> +set_target_properties(setupldr PROPERTIES LINK_FLAGS "-Wl,--strip-all -Wl,-entry,_mainCRTStartup -Wl,--image-base,0x8000 -Wl,--exclude-all-symbols -Wl,--subsystem,native" SUFFIX ".sys")
>
> +if(ARCH MATCHES i386)
> +target_link_libraries(setupldr mini_hal)
> +endif(ARCH MATCHES i386)
>
> +target_link_libraries(setupldr
> rossym
> cmlib
> rtl
> libcntpr)
>
> +add_pch(setupldr ${CMAKE_CURRENT_SOURCE_DIR}/freeldr/freeldr/include/freeldr.h ${SETUPLDR_SOURCE})
>
> Copied: branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.S (from r48568, branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm)
> URL: http://svn.reactos.org/svn/reactos/branches/cmake-bringup/boot/freeldr/freel...
> ==============================================================================
> --- branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm [iso-8859-1] (original)
> +++ branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.S [iso-8859-1] Thu Sep  2 17:39:45 2010
> @@ -1,226 +1,222 @@
> -; FATHELP.ASM
> -; FAT12/16 Boot Sector Helper Code
> -; Copyright (c) 1998, 2001, 2002, 2003 Brian Palmer
>
> -;org 8000h
>
> -segment .text
>
> -bits 16
>
> -BootSectorStackTop             equ             0x7bf2
> -DataAreaStartHigh              equ             0x2
> -DataAreaStartLow               equ             0x4
> -BiosCHSDriveSizeHigh   equ             0x6
> -BiosCHSDriveSizeLow            equ             0x8
> -BiosCHSDriveSize               equ             0x8
> -ReadSectorsOffset              equ             0xa
> -ReadClusterOffset              equ             0xc
> -PutCharsOffset                 equ             0xe
>
> -OEMName                                        equ             3
> -BytesPerSector                 equ             11
> -SectsPerCluster                        equ             13
> -ReservedSectors                        equ             14
> -NumberOfFats                   equ             16
> -MaxRootEntries                 equ             17
> -TotalSectors                   equ             19
> -MediaDescriptor                        equ             21
> -SectorsPerFat                  equ             22
> -SectorsPerTrack                        equ             24
> -NumberOfHeads                  equ             26
> -HiddenSectors                  equ             28
> -TotalSectorsBig                        equ             32
> -BootDrive                              equ             36
> -Reserved                               equ             37
> -ExtendSig                              equ             38
> -SerialNumber                   equ             39
> -VolumeLabel                            equ             43
> -FileSystem                             equ             54
>
> -BootPartition                  equ             0x7dfd
> +// FATHELP.ASM
> +// FAT12/16 Boot Sector Helper Code
> +// Copyright (c) 1998, 2001, 2002, 2003 Brian Palmer
> .text
> .code16
> .intel_syntax
>
> +#define BootSectorStackTop             0x7bf2
> +#define DataAreaStartHigh              0x2
> +#define DataAreaStartLow               0x4
> +#define BiosCHSDriveSizeHigh   0x6
> +#define BiosCHSDriveSizeLow            0x8
> +#define BiosCHSDriveSize               0x8
> +#define ReadSectorsOffset              0xa
> +#define ReadClusterOffset              0xc
> +#define PutCharsOffset                 0xe
>
> +#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                                  0x7dfd
>
> -; 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.
> -;
> -; This code is loaded at 0000:8000 so we have to
> -; encode a jmp instruction to jump to 0000:8200
>
> -global _mainCRTStartup ; For Mingw32 builds where the linker looks for this symbol
> +// 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.
> +//
> +// This code is loaded at 0000:8000 so we have to
> +// encode a jmp instruction to jump to 0000:8200
>
> +.globl _mainCRTStartup                                         /* For Mingw32 builds where the linker looks for this symbol */
>  _mainCRTStartup:
> -global start
> +.globl start
>  start:
> db     0xe9
> db      0xfd
> db      0x01
>
> -; 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.
> .byte   0xe9
> .byte   0xfd
> .byte   0x01
>
> +// 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:
> push ax                                                 ; First save AX - the start cluster of freeldr.sys
> ; Display "Loading FreeLoader..." message
> mov  esi,msgLoading                            ; Loading message
> call [bp-PutCharsOffset]               ; Display it
> push %ax                                                        /* First save AX - the start cluster of freeldr.sys */
> // Display "Loading FreeLoader..." message
> mov  %esi,msgLoading                           /* Loading message */
> call [%bp-PutCharsOffset]                      /* Display it */
>
> call ReadFatIntoMemory
> pop  ax                                                 ; Restore AX (start cluster)
> ; AX has start cluster of freeldr.sys
> mov  bx,800h
> mov  es,bx
> pop  %ax                                                        /* Restore AX (start cluster) */
> // AX has start cluster of freeldr.sys
> mov  %bx,0x800
> mov  %es,%bx
>
> LoadFile:
> push ax
> push %ax
>
> call IsFat12
> pop  ax
> pop  %ax
>
> jnc  LoadFile2
> cmp  ax,0ff8h               ; Check to see if this is the last cluster in the chain
> cmp  %ax,0xff8                                          /* Check to see if this is the last cluster in the chain */
>
> jmp  LoadFile3
>  LoadFile2:
> cmp  ax,0fff8h
> cmp  %ax,0xfff8
>
> 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 [bp-ReadClusterOffset]
> pop  es
> xor  bx,bx
> mov  bl,BYTE [BYTE 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
> 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 [%bp-ReadClusterOffset]
> pop  %es
> xor  %bx,%bx
> mov  %bl,BYTE [%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
> pop  %ax
> push %es
>
> jnc  LoadFile4
> call GetFatEntry12                                      ; Get the next entry
> call GetFatEntry12                                      /* Get the next entry */
>
> jmp  LoadFile5
>  LoadFile4:
>                call GetFatEntry16
>  LoadFile5:
> pop  es
> jmp  LoadFile                                          ; Load the next cluster (if any)
> pop  %es
> jmp  LoadFile                                          /* Load the next cluster (if any) */
>
> LoadFile_Done:
> mov  dl,BYTE [BYTE 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
> mov  %dl,BYTE [%bp+BootDrive]          /* Load the boot drive into DL */
> mov  %dh,[BootPartition]                        /* Load the boot partition into DH */
> push 0                                                          /* push segment (0x0000) */
> mov %bx, [0x80A8]                                       /* 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:
> mov   ax,WORD [BYTE bp+HiddenSectors]
> mov   dx,WORD [BYTE bp+HiddenSectors+2]
> add   ax,WORD [BYTE bp+ReservedSectors]
> adc   dx,byte 0
> mov   cx,WORD [BYTE bp+SectorsPerFat]
> mov   bx,7000h
> mov   es,bx
> xor   bx,bx
> call  [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
> mov   %ax,WORD [%bp+HiddenSectors]
> mov   %dx,WORD [%bp+HiddenSectors+2]
> add   %ax,WORD [%bp+ReservedSectors]
> adc   %dx,0
> mov   %cx,WORD [%bp+SectorsPerFat]
> mov   %bx,0x7000
> mov   %es,%bx
> xor   %bx,%bx
> call  [%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,7000h
> add   bx,dx
> mov   es,bx
> mov   bx,ax                                             ; Restore FAT entry offset
> mov   ax,WORD [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
> mov   %cx,2                                                     /* AX = AX * 2 (since FAT16 entries are 2 bytes) */
> mul   %cx
> shl   %dx,12
> mov   %bx,0x7000
> add   %bx,%dx
> mov   %es,%bx
> mov   %bx,%ax                                           /* Restore FAT entry offset */
> es mov   %ax,WORD [%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,7000h
> mov   es,bx
> mov   bx,ax                                             ; Put FAT entry offset into BX
> mov   ax,WORD [es:bx]           ; Get FAT entry
> pop   cx                                                ; Get cluster number from stack
> and   cx,1
> 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,0x7000
> mov   %es,%bx
> mov   %bx,%ax                                           /* Put FAT entry offset into BX */
> es mov   %ax,WORD [%bx]                         /* Get FAT entry */
> pop   %cx                                                       /* Get cluster number from stack */
> and   %cx,1
>
> jz    UseLow12Bits
> and   ax,0fff0h
> shr   ax,4
> and   %ax,0xfff0
> shr   %ax,4
>
> jmp   GetFatEntry12_Done
>
> UseLow12Bits:
> and   ax,0fffh
> and   %ax,0x0fff
>
> GetFatEntry12_Done:
>
> ret
>
> -; Returns CF = 1 if this is a FAT12 file system
> -; Otherwise CF = 0 for FAT16
> +// Returns CF = 1 if this is a FAT12 file system
> +// Otherwise CF = 0 for FAT16
>  IsFat12:
> mov   ebx,DWORD [BYTE 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 [BYTE bp+HiddenSectors]
> xor   eax,eax
> mov   ax,WORD [BYTE bp+TotalSectors]
> cmp   ax,byte 0
> mov   %ebx,DWORD [%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 [%bp+HiddenSectors]
> xor   %eax,%eax
> mov   %ax,WORD [%bp+TotalSectors]
> cmp   %ax,0
>
> jnz   IsFat12_2
> mov   eax,DWORD [BYTE bp+TotalSectorsBig]
> ; EAX now contains the number of sectors on the volume
> mov   %eax,DWORD [%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 [BYTE bp+SectsPerCluster]
> div   ebx
> ; EAX now has the number of clusters on the volume
> 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
> xor %ebx,%ebx
> mov %bl,BYTE [%bp+SectsPerCluster]
> div   %ebx
> // EAX now has the number of clusters on the volume
>
> stc
> cmp   eax,4085
> cmp   %eax,4085
>
> jb    IsFat12_Done
>                clc
>
> @@ -229,7 +225,9 @@
>
> -msgLoading     db 'Loading FreeLoader...',0dh,0ah,0
> times 510-($-$$) db 0   ; Pad to 510 bytes
> dw 0aa55h                               ; BootSector signature
>
> +msgLoading:
> .asciz "Loading FreeLoader...\r\n"
> .org 0x1fe
>
> +blockend:
> .word 0x0aa55                                           /* BootSector signature */
>
> Removed: branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm
> URL: http://svn.reactos.org/svn/reactos/branches/cmake-bringup/boot/freeldr/freel...
> ==============================================================================
> --- branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm [iso-8859-1] (original)
> +++ branches/cmake-bringup/boot/freeldr/freeldr/arch/i386/fathelp.asm (removed)
> @@ -1,235 +1,0 @@
> -; FATHELP.ASM
> -; FAT12/16 Boot Sector Helper Code
> -; Copyright (c) 1998, 2001, 2002, 2003 Brian Palmer
>
> -;org 8000h
>
> -segment .text
>
> -bits 16
>
> -BootSectorStackTop             equ             0x7bf2
> -DataAreaStartHigh              equ             0x2
> -DataAreaStartLow               equ             0x4
> -BiosCHSDriveSizeHigh   equ             0x6
> -BiosCHSDriveSizeLow            equ             0x8
> -BiosCHSDriveSize               equ             0x8
> -ReadSectorsOffset              equ             0xa
> -ReadClusterOffset              equ             0xc
> -PutCharsOffset                 equ             0xe
>
> -OEMName                                        equ             3
> -BytesPerSector                 equ             11
> -SectsPerCluster                        equ             13
> -ReservedSectors                        equ             14
> -NumberOfFats                   equ             16
> -MaxRootEntries                 equ             17
> -TotalSectors                   equ             19
> -MediaDescriptor                        equ             21
> -SectorsPerFat                  equ             22
> -SectorsPerTrack                        equ             24
> -NumberOfHeads                  equ             26
> -HiddenSectors                  equ             28
> -TotalSectorsBig                        equ             32
> -BootDrive                              equ             36
> -Reserved                               equ             37
> -ExtendSig                              equ             38
> -SerialNumber                   equ             39
> -VolumeLabel                            equ             43
> -FileSystem                             equ             54
>
> -BootPartition                  equ             0x7dfd
>
> -; 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.
> -;
> -; This code is loaded at 0000:8000 so we have to
> -; encode a jmp instruction to jump to 0000:8200
>
> -global _mainCRTStartup ; For Mingw32 builds where the linker looks for this symbol
> -_mainCRTStartup:
> -global start
> -start:
> db     0xe9
> db      0xfd
> db      0x01
>
> -; 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:
> push ax                                                 ; First save AX - the start cluster of freeldr.sys
> ; Display "Loading FreeLoader..." message
> mov  esi,msgLoading                            ; Loading message
> call [bp-PutCharsOffset]               ; Display it
> call ReadFatIntoMemory
> pop  ax                                                 ; Restore AX (start cluster)
> ; AX has start cluster of freeldr.sys
> mov  bx,800h
> mov  es,bx
>
> -LoadFile:
> push ax
> call IsFat12
> pop  ax
> jnc  LoadFile2
> cmp  ax,0ff8h               ; Check to see if this is the last cluster in the chain
> jmp  LoadFile3
>
> -LoadFile2:
> cmp  ax,0fff8h
>
> -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 [bp-ReadClusterOffset]
> pop  es
> xor  bx,bx
> mov  bl,BYTE [BYTE 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 [BYTE 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:
> mov   ax,WORD [BYTE bp+HiddenSectors]
> mov   dx,WORD [BYTE bp+HiddenSectors+2]
> add   ax,WORD [BYTE bp+ReservedSectors]
> adc   dx,byte 0
> mov   cx,WORD [BYTE bp+SectorsPerFat]
> mov   bx,7000h
> mov   es,bx
> xor   bx,bx
> call  [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,7000h
> add   bx,dx
> mov   es,bx
> mov   bx,ax                                             ; Restore FAT entry offset
> mov   ax,WORD [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,7000h
> mov   es,bx
> mov   bx,ax                                             ; Put FAT entry offset into BX
> mov   ax,WORD [es:bx]           ; Get FAT entry
> pop   cx                                                ; Get cluster number from stack
> and   cx,1
> jz    UseLow12Bits
> and   ax,0fff0h
> shr   ax,4
> jmp   GetFatEntry12_Done
>
> -UseLow12Bits:
> and   ax,0fffh
>
> -GetFatEntry12_Done:
> ret
>
> -; Returns CF = 1 if this is a FAT12 file system
> -; Otherwise CF = 0 for FAT16
> -IsFat12:
> mov   ebx,DWORD [BYTE 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 [BYTE bp+HiddenSectors]
> xor   eax,eax
> mov   ax,WORD [BYTE bp+TotalSectors]
> cmp   ax,byte 0
> jnz   IsFat12_2
> mov   eax,DWORD [BYTE 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 [BYTE 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     db 'Loading FreeLoader...',0dh,0ah,0
> times 510-($-$$) db 0   ; Pad to 510 bytes
> dw 0aa55h                               ; BootSector signature