[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.S... ============================================================================== --- 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/fat32... ============================================================================== --- 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/isobo... ============================================================================== --- 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/CMakeL... ============================================================================== --- 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/i... ============================================================================== --- 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/r... ============================================================================== --- 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/r... ============================================================================== --- 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/r... ============================================================================== --- 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/r... ============================================================================== --- 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 ------------------------------------------------------------------------------ svn:eol-style = native
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tkreuzer＠svn.reactos.org