diff options
Diffstat (limited to 'xorg-server/hw/xfree86/int10/INT10.HOWTO')
| -rw-r--r-- | xorg-server/hw/xfree86/int10/INT10.HOWTO | 688 |
1 files changed, 344 insertions, 344 deletions
diff --git a/xorg-server/hw/xfree86/int10/INT10.HOWTO b/xorg-server/hw/xfree86/int10/INT10.HOWTO index e2154c1c3..f2f08ceec 100644 --- a/xorg-server/hw/xfree86/int10/INT10.HOWTO +++ b/xorg-server/hw/xfree86/int10/INT10.HOWTO @@ -1,344 +1,344 @@ - - INT10 X86 Real Mode executor - ============================= - - PRELIMINARY - -INT10 is a XFree86 module for soft-booting and executing real mode -int10 BIOS calls. The BIOS call code is largely untested, yet. - -1. Usage -======== - -To use the int10 module in a driver the header file -xfree86/os-support/int10/xf86int10.h must be included. - - a. Initialization - ----------------- - -The int10-executer gets initialized by calling: - - xf86Int10InfoPtr xf86InitInt10(int entityIndex); - -The function will soft-boot any non-primary device and return a -pointer to a xf86Int10InfoRec on success. If anything fails or if -int10 execution is disabled by an option in the device section NULL -will be returned. The driver should store this pointer for later -calls to other int10 module functions. - - b. Memory allocation - -------------------- - -To allocate memory in the real mode execution environment - - void * xf86Int10AllocPages(xf86Int10InfoPtr pInt,int num, int *off); - -can be called. It allocates num consecutive pagesize chunks. It -returns the address of the allocated area. off is set to its offset in -the real mode memory space. - - void xf86Int10FreePages(xf86Int10InfoPtr pInt, void *pbase, int num); - -Is used to free num pages beginning at pbase. - - c. Doing int10 BIOS calls - ------------------------- - -The BIOS call is executed by calling: - - void xf86ExecX86int10(xf86Int10InfoPtr pInt); - -The number of the interrupt (normally 10) and the initial values of -the ax, bx, cx, dx, si, di and es x86-CPU registers can be set in the -xf86Int10InfoRec passed to the function. On return this structure -contains the exit values of the registers listed above and the CPU -flag register. - - d. De-initializing - ----------------- - -If no further int10 calls are required for a certain chipset -the driver should call: - - void xf86FreeInt10(xf86Int10InfoPtr pInt); - -to free the memory allocated for real mode int10 calls. - - -2. Porting issues -================= - -The int10 real mode executor is designed to run on top of various x86 -CPU emulators as well as in vm86 mode of a real x86 CPU. If used with -a CPU emulator the emulator and CPU specific interfaces can be held -separate thus requiring minimal efforts to port the int10 module to -new platforms. Currently an interface to the x86emu real mode -emulator is provided. Since details of setting up and running the -vm86 mode is platform dependent both the platform dependent -environment and the emulation layer have to be ported. Several helper -functions are provided for that. - -A CPU emulator should meet certain requirements to be usable -for the INT10 executor: - -1. It must trap calls to intXX instructions and pass execution to an - external function which is allowed to modify CPU registers - including the instruction pointer (IP) before returning to the - emulator for continuing execution. When the external function is - called the IP must point to the instruction past the intXX call. - -2. The emulator should use externally provided functions to handle - PIO. - -3. The emulator should be able to use externally provided functions - to access memory from the real mode memory environment. Note, that - the vm86 mode usually requires one hunk of consecutive memory - starting at address 0 in the process virtual memory space. Thus if - this mode is to be used, the OS environment has to be able to provide - that, ie. it must be able to remap the processes virtual memory space - onto itself. If the emulator is able to handle memory access thru - externally provided functions the real mode process memory can be - located anywhere in the processes virtual memory. It does not even - have to be consecutive. - -4. The executor should terminate on encountering a 'hlt' instruction. - - -Functions to implement: - -To simplify development the code has been split into a general setup -part and an emulator specific one. A generic setup code is provided in -generic.c. It should be usable with any emulator satisfying the -conditions mentioned above. Therefore the following section on int10 -setup may be skipped when porting int10 to new emulator. - -If the vm86() is to be used no memory access functions can be used. -Therefore the layout of the real mode memory image has to meet certain -requirements. Therefore when porting to other platforms a new setup -code may have to be designed, too. The following section will give -guidelines how this may be done. A sample implementation using SysV -IPC to map the appropriate real mode memory image to address 0 in -virtual address space just prior to execution may be found in -xfree86/os-support/linux/int10/linux.c. - -On non-PC like platforms emulation of certain PC features such as -initialization of BIOS int vectors, sys_BIOS constants or PCI config -method 1 can be turned on by defining _PC. - -I. Setup Code -------------- - -This sets up the real mode memory image, calls the emulator to POST -the chipset if required and maintains memory allocations in real mode -address space. - -1. xf86Int10InfoPtr xf86InitInt10(int entityIndex); - -This function should first find the screen assigned to the entity -carrying entitiyIndex and then call - - Bool int10skip(ScrnInfoPtr pScrn) - -to find out if the user has requested not to initialize int10. If so -xf86InitInt10() should return NULL. Otherwise an xf86Int10InfoRec -should be allocated. This structure contains the following fields: - - a. int entityIndex - index of the entity whose BIOS is to be - executed. - b. int scrnIndex - index of the screen assigned the entity. - c. pointer cpuRegs - pointer to a emulator/vm86-mode private - structure. May hold cpu register values - for the emulator. - d. CARD16 BIOSseg - Video BIOS segment address. - e. pointer private - pointer to a os specific data structure. - f. struct _int10Mem* - pointer to a structure to hold the memory - access functions for use by an emulator. - g. int num - number of the int to be called. - h. int ax..es,flags - CPU register values to pass to int-call. - -The Init function should initialize a-f. To initialize the emulator -specific execute environment the function - - Bool xf86Int10ExecSetup(xf86Int10InfoPtr pInt) - -should be called. If this function returns FALSE any already allocated -memory should be freed and xf86Int10Init(0 should exit returning NULL. - -If the platform has a PC like system BIOS it may be copied to or -mapped into memory locations SYS_BIOS to SYS_SIZE-1 of the real mode -memory environment of this process. Otherwise the helper function: - -int setup_system_bios(CARD32 base_addr); - -may be called to set up a rudimentary system BIOS sufficient to be -used to boot video BIOSes. base_addr specifies the virtual address -corresponding to SYS_BIOS in the real mode environment. If a PC-like -int vector and BIOS data area is available it should be copied to 0 to -LOW_PAGE_SIZE of the entities real mode environment. In this case the -video interrupt related entries should be reset for all non-primary -cards by calling: - -void reset_int_vect(xf86Int10InfoPtr pInt); To initialize the - -correct video BIOS entry points the BIOS must be warm-booted. If no -PC-like int vector is available one can be set up by calling - -void setup_int_vect(xf86Int10InfoPtr pInt); - -In this case the video BIOS has to be warm-booted always. If the -video BIOS for this entity has been installed during boot it may be -mapped (or copied) directly to the correct address in the real mode -memory environment. Otherwise - -int mapPciRom(xf86Int10InfoPtr pInt, unsigned char * address); - -should be called to copy the BIOS image from PCI ROM. 'address' -specifies the address this image should be copied to. Sufficient space -to hold an entire BIOS image should be allocated prior to calling -mapPciRom(). This function will return the size of the BIOS image in -bytes if it was able to successfully copy the image and 0 -otherwise. To create a well defined point to exit the softbooter - -void set_return_trap(xf86Int10Ptr pInt); - -may be called. It sets up a 'hlt' instruction in the emulator memory -just above the BIOS variable area. Before entering real mode execution -this address will be pushed onto the return stack. If the BIOS needs -to be warm-booted this should be done before leaving xf86InitInt10() -by setting num in the xf86Int10InfoRec to 0xe6 and calling - -void xf86ExecX86int10(xf86Int10IfoPtr pInt); - -The implementation of this function will be discussed below. This -function should be wrapped by calls to void LockLegacyVGA(screen, -legacyVGAPtr vga); and void UnlockLegacyVGA(screen, legacyVGAPtr vga); -The struct vga is used to hold the state of the legacy VGA access -registers if a legacy VGA device exists. xf86InitInt10() should -return a pointer to the xf86Int10InfoRec allocated. - -2. Bool MapCurrentInt10(xf86Int10InfoPtr pInt); - -In case a platform specific mapping has to be performed to map the -memory allocated for the real mode memory environment into a specific -location prior to executing the x86 real mode code a function - - Bool MapCurrentInt10(xf86Int10InfoPtr pInt); - -has to be provided. It will be called by a helper function whenever -the active entity changes. If the vm86 mode is used it is most likely -that the 1MB real mode memory space located somewhere in the processes -virtual memory will have to be remapped to address 0 of the virtual -memory space. - -3. void xf86FreeInt10(xf86Int10InfoPtr pInt); - -To free all memory allocated for video BIOS calls of a specific entity -the function - - void xf86FreeInt10(xf86Int10InfoPtr pInt); - -should be provided. If the entity to be freed was mapped by -MapCurrentInt10() this mapping needs to be undone also. - -4. - void * xf86Int10AllocPages(xf86Int10InfoPtr pInt,int num, int *off) - void xf86Int10FreePages(xf86Int10InfoPtr pInt, void *pbase, int num) - -xf86Int10AllocPages() should allocate 'num' consecutive page-size -chunks of memory. In real mode memory space this range needs to occupy -consecutive addresses, too. The function must return the address of -this memory. The offset in real mode memory needs to be returned in -'off'. If no block of 'num' pages are available the function should -return NULL. - -xf86Int10FreePages() will free the 'num' pages starting at 'pbase'. -'num' is equal to the number of pages allocated by a single -xf86Int10AllocatePages() call. 'pbase' is the address of the range -previously returned by xf86Int10AllocatePages(). - -II. Emulator specific functions -------------------------------- - -1. Bool xf86Int10ExecSetup(xf86Int10InfoPtr pInt); - -This function will be called from xf86InitInt10(). It may be used to -set up the static emulator specific part of the real mode -environment. On success it should return TRUE. - -2. xf86ExecX86int10(xf86Int10InfoPtr pInt); - -This function gets called to execute an int call. It may call the -helper function: - - void setup_int(xf86Int10InfoPrt pInt); - -to copy the register values to the emulator specific locations and to -set up the non-static real mode execution environment. On return from -setup_int() 'Int10Current' holds a pointer to the current -xf86Int10InfoRec. - -It should start execution by calling - - Bool int_handler(xf86Int10InfoPtr pInt); - -and if this function returns TRUE it should call whatever necessary to -continue execution until a 'hlt' instruction is encountered. To copy -the resulting register values back to the xf86Int10InfoRec structure - - void finish_int(xf86Int10InfoPtr pInt); - -should be called. - -Helper functions are provided to aid the implementation of a vm86 -call: - - Bool vm86_GP_fault(xf86Int10InfoPtr pInt); - -This function handles instructions which cause a vm86 call to -trap. PIO access is handled by the in/out calls as defined in -compiler.h. Optionally the PIO instructions can be logged by defining -PRINT_PORT in xf86int10.h. This is meant for debugging purposes. - -Unknown instructions and 'hlt' cause vm86_GP_fault() to return -FALSE. Otherwise TRUE is returned. - -Note: This function is currently based on the Linux vm86 call. It -might have to be modified or even rewritten for other OS. So your -milage may vary. - -Functions to dump memory, code, xf86 CPU register values and stack are -also provided. Take a look at helper.c To view a memory range the -function - - void dprint(unsigned long start, unsigned long size) - -is provided. The use should be self explanatory. - -Register and memory access functions are provided in helper_mem.c. -The PIO register access functions can trap access to PCI config space -access register (config method 1) if _PC is not defined. - -A header file 'defines.h' is required to define OS/emulator specific -ways to access memory and xf86 CPU registers: Defines need to be -provided for memory byte/work/long read/write access -(MEM_RB(name,addr),MEM_RW(name,addr),MEM_RL(name,addr), -MEM_WB(name,addr,val),MEM_WL(name,addr,val),MEM_WL(name,addr,val)) of -the real mode memory environment. 'name' will contain a pointer to the -current xf86Int10InfoRec. Currently defines are available for -vm86-mode under Linux and x86emu. They may be activated by defining -_X86EMU or _VM86_LINUX respectively. - -Note: Emulators usually are not able to pass this pointer when calling -memory access functions. In this case a global variable should be -defined which can hold this pointer. This variable can be set in -MapCurrentInt10(). It also must be set in xf86InitInt10() if this -function calls the memory access functions either directly or by -calling xf86ExecX86int10(pInt). Defines to access the emulator -specific xf86 CPU register locations are also required: -X86_EAX,...,X86_EFLAGS for access of the full 32 bit registers, -X86_AX...X86_FLAGS for access of the 16 bit registers and -XF86_AL,XF86_BL,XF86_CL,XF86_DL to access the lower byte of the -AX,BX,CX and DX register. - - -$XFree86: xc/programs/Xserver/hw/xfree86/int10/INT10.HOWTO,v 1.2 2000/02/08 13:13:22 eich Exp $ +
+ INT10 X86 Real Mode executor
+ =============================
+
+ PRELIMINARY
+
+INT10 is a XFree86 module for soft-booting and executing real mode
+int10 BIOS calls. The BIOS call code is largely untested, yet.
+
+1. Usage
+========
+
+To use the int10 module in a driver the header file
+xfree86/os-support/int10/xf86int10.h must be included.
+
+ a. Initialization
+ -----------------
+
+The int10-executer gets initialized by calling:
+
+ xf86Int10InfoPtr xf86InitInt10(int entityIndex);
+
+The function will soft-boot any non-primary device and return a
+pointer to a xf86Int10InfoRec on success. If anything fails or if
+int10 execution is disabled by an option in the device section NULL
+will be returned. The driver should store this pointer for later
+calls to other int10 module functions.
+
+ b. Memory allocation
+ --------------------
+
+To allocate memory in the real mode execution environment
+
+ void * xf86Int10AllocPages(xf86Int10InfoPtr pInt,int num, int *off);
+
+can be called. It allocates num consecutive pagesize chunks. It
+returns the address of the allocated area. off is set to its offset in
+the real mode memory space.
+
+ void xf86Int10FreePages(xf86Int10InfoPtr pInt, void *pbase, int num);
+
+Is used to free num pages beginning at pbase.
+
+ c. Doing int10 BIOS calls
+ -------------------------
+
+The BIOS call is executed by calling:
+
+ void xf86ExecX86int10(xf86Int10InfoPtr pInt);
+
+The number of the interrupt (normally 10) and the initial values of
+the ax, bx, cx, dx, si, di and es x86-CPU registers can be set in the
+xf86Int10InfoRec passed to the function. On return this structure
+contains the exit values of the registers listed above and the CPU
+flag register.
+
+ d. De-initializing
+ -----------------
+
+If no further int10 calls are required for a certain chipset
+the driver should call:
+
+ void xf86FreeInt10(xf86Int10InfoPtr pInt);
+
+to free the memory allocated for real mode int10 calls.
+
+
+2. Porting issues
+=================
+
+The int10 real mode executor is designed to run on top of various x86
+CPU emulators as well as in vm86 mode of a real x86 CPU. If used with
+a CPU emulator the emulator and CPU specific interfaces can be held
+separate thus requiring minimal efforts to port the int10 module to
+new platforms. Currently an interface to the x86emu real mode
+emulator is provided. Since details of setting up and running the
+vm86 mode is platform dependent both the platform dependent
+environment and the emulation layer have to be ported. Several helper
+functions are provided for that.
+
+A CPU emulator should meet certain requirements to be usable
+for the INT10 executor:
+
+1. It must trap calls to intXX instructions and pass execution to an
+ external function which is allowed to modify CPU registers
+ including the instruction pointer (IP) before returning to the
+ emulator for continuing execution. When the external function is
+ called the IP must point to the instruction past the intXX call.
+
+2. The emulator should use externally provided functions to handle
+ PIO.
+
+3. The emulator should be able to use externally provided functions
+ to access memory from the real mode memory environment. Note, that
+ the vm86 mode usually requires one hunk of consecutive memory
+ starting at address 0 in the process virtual memory space. Thus if
+ this mode is to be used, the OS environment has to be able to provide
+ that, ie. it must be able to remap the processes virtual memory space
+ onto itself. If the emulator is able to handle memory access thru
+ externally provided functions the real mode process memory can be
+ located anywhere in the processes virtual memory. It does not even
+ have to be consecutive.
+
+4. The executor should terminate on encountering a 'hlt' instruction.
+
+
+Functions to implement:
+
+To simplify development the code has been split into a general setup
+part and an emulator specific one. A generic setup code is provided in
+generic.c. It should be usable with any emulator satisfying the
+conditions mentioned above. Therefore the following section on int10
+setup may be skipped when porting int10 to new emulator.
+
+If the vm86() is to be used no memory access functions can be used.
+Therefore the layout of the real mode memory image has to meet certain
+requirements. Therefore when porting to other platforms a new setup
+code may have to be designed, too. The following section will give
+guidelines how this may be done. A sample implementation using SysV
+IPC to map the appropriate real mode memory image to address 0 in
+virtual address space just prior to execution may be found in
+xfree86/os-support/linux/int10/linux.c.
+
+On non-PC like platforms emulation of certain PC features such as
+initialization of BIOS int vectors, sys_BIOS constants or PCI config
+method 1 can be turned on by defining _PC.
+
+I. Setup Code
+-------------
+
+This sets up the real mode memory image, calls the emulator to POST
+the chipset if required and maintains memory allocations in real mode
+address space.
+
+1. xf86Int10InfoPtr xf86InitInt10(int entityIndex);
+
+This function should first find the screen assigned to the entity
+carrying entitiyIndex and then call
+
+ Bool int10skip(ScrnInfoPtr pScrn)
+
+to find out if the user has requested not to initialize int10. If so
+xf86InitInt10() should return NULL. Otherwise an xf86Int10InfoRec
+should be allocated. This structure contains the following fields:
+
+ a. int entityIndex - index of the entity whose BIOS is to be
+ executed.
+ b. int scrnIndex - index of the screen assigned the entity.
+ c. pointer cpuRegs - pointer to a emulator/vm86-mode private
+ structure. May hold cpu register values
+ for the emulator.
+ d. CARD16 BIOSseg - Video BIOS segment address.
+ e. pointer private - pointer to a os specific data structure.
+ f. struct _int10Mem* - pointer to a structure to hold the memory
+ access functions for use by an emulator.
+ g. int num - number of the int to be called.
+ h. int ax..es,flags - CPU register values to pass to int-call.
+
+The Init function should initialize a-f. To initialize the emulator
+specific execute environment the function
+
+ Bool xf86Int10ExecSetup(xf86Int10InfoPtr pInt)
+
+should be called. If this function returns FALSE any already allocated
+memory should be freed and xf86Int10Init(0 should exit returning NULL.
+
+If the platform has a PC like system BIOS it may be copied to or
+mapped into memory locations SYS_BIOS to SYS_SIZE-1 of the real mode
+memory environment of this process. Otherwise the helper function:
+
+int setup_system_bios(CARD32 base_addr);
+
+may be called to set up a rudimentary system BIOS sufficient to be
+used to boot video BIOSes. base_addr specifies the virtual address
+corresponding to SYS_BIOS in the real mode environment. If a PC-like
+int vector and BIOS data area is available it should be copied to 0 to
+LOW_PAGE_SIZE of the entities real mode environment. In this case the
+video interrupt related entries should be reset for all non-primary
+cards by calling:
+
+void reset_int_vect(xf86Int10InfoPtr pInt); To initialize the
+
+correct video BIOS entry points the BIOS must be warm-booted. If no
+PC-like int vector is available one can be set up by calling
+
+void setup_int_vect(xf86Int10InfoPtr pInt);
+
+In this case the video BIOS has to be warm-booted always. If the
+video BIOS for this entity has been installed during boot it may be
+mapped (or copied) directly to the correct address in the real mode
+memory environment. Otherwise
+
+int mapPciRom(xf86Int10InfoPtr pInt, unsigned char * address);
+
+should be called to copy the BIOS image from PCI ROM. 'address'
+specifies the address this image should be copied to. Sufficient space
+to hold an entire BIOS image should be allocated prior to calling
+mapPciRom(). This function will return the size of the BIOS image in
+bytes if it was able to successfully copy the image and 0
+otherwise. To create a well defined point to exit the softbooter
+
+void set_return_trap(xf86Int10Ptr pInt);
+
+may be called. It sets up a 'hlt' instruction in the emulator memory
+just above the BIOS variable area. Before entering real mode execution
+this address will be pushed onto the return stack. If the BIOS needs
+to be warm-booted this should be done before leaving xf86InitInt10()
+by setting num in the xf86Int10InfoRec to 0xe6 and calling
+
+void xf86ExecX86int10(xf86Int10IfoPtr pInt);
+
+The implementation of this function will be discussed below. This
+function should be wrapped by calls to void LockLegacyVGA(screen,
+legacyVGAPtr vga); and void UnlockLegacyVGA(screen, legacyVGAPtr vga);
+The struct vga is used to hold the state of the legacy VGA access
+registers if a legacy VGA device exists. xf86InitInt10() should
+return a pointer to the xf86Int10InfoRec allocated.
+
+2. Bool MapCurrentInt10(xf86Int10InfoPtr pInt);
+
+In case a platform specific mapping has to be performed to map the
+memory allocated for the real mode memory environment into a specific
+location prior to executing the x86 real mode code a function
+
+ Bool MapCurrentInt10(xf86Int10InfoPtr pInt);
+
+has to be provided. It will be called by a helper function whenever
+the active entity changes. If the vm86 mode is used it is most likely
+that the 1MB real mode memory space located somewhere in the processes
+virtual memory will have to be remapped to address 0 of the virtual
+memory space.
+
+3. void xf86FreeInt10(xf86Int10InfoPtr pInt);
+
+To free all memory allocated for video BIOS calls of a specific entity
+the function
+
+ void xf86FreeInt10(xf86Int10InfoPtr pInt);
+
+should be provided. If the entity to be freed was mapped by
+MapCurrentInt10() this mapping needs to be undone also.
+
+4.
+ void * xf86Int10AllocPages(xf86Int10InfoPtr pInt,int num, int *off)
+ void xf86Int10FreePages(xf86Int10InfoPtr pInt, void *pbase, int num)
+
+xf86Int10AllocPages() should allocate 'num' consecutive page-size
+chunks of memory. In real mode memory space this range needs to occupy
+consecutive addresses, too. The function must return the address of
+this memory. The offset in real mode memory needs to be returned in
+'off'. If no block of 'num' pages are available the function should
+return NULL.
+
+xf86Int10FreePages() will free the 'num' pages starting at 'pbase'.
+'num' is equal to the number of pages allocated by a single
+xf86Int10AllocatePages() call. 'pbase' is the address of the range
+previously returned by xf86Int10AllocatePages().
+
+II. Emulator specific functions
+-------------------------------
+
+1. Bool xf86Int10ExecSetup(xf86Int10InfoPtr pInt);
+
+This function will be called from xf86InitInt10(). It may be used to
+set up the static emulator specific part of the real mode
+environment. On success it should return TRUE.
+
+2. xf86ExecX86int10(xf86Int10InfoPtr pInt);
+
+This function gets called to execute an int call. It may call the
+helper function:
+
+ void setup_int(xf86Int10InfoPrt pInt);
+
+to copy the register values to the emulator specific locations and to
+set up the non-static real mode execution environment. On return from
+setup_int() 'Int10Current' holds a pointer to the current
+xf86Int10InfoRec.
+
+It should start execution by calling
+
+ Bool int_handler(xf86Int10InfoPtr pInt);
+
+and if this function returns TRUE it should call whatever necessary to
+continue execution until a 'hlt' instruction is encountered. To copy
+the resulting register values back to the xf86Int10InfoRec structure
+
+ void finish_int(xf86Int10InfoPtr pInt);
+
+should be called.
+
+Helper functions are provided to aid the implementation of a vm86
+call:
+
+ Bool vm86_GP_fault(xf86Int10InfoPtr pInt);
+
+This function handles instructions which cause a vm86 call to
+trap. PIO access is handled by the in/out calls as defined in
+compiler.h. Optionally the PIO instructions can be logged by defining
+PRINT_PORT in xf86int10.h. This is meant for debugging purposes.
+
+Unknown instructions and 'hlt' cause vm86_GP_fault() to return
+FALSE. Otherwise TRUE is returned.
+
+Note: This function is currently based on the Linux vm86 call. It
+might have to be modified or even rewritten for other OS. So your
+milage may vary.
+
+Functions to dump memory, code, xf86 CPU register values and stack are
+also provided. Take a look at helper.c To view a memory range the
+function
+
+ void dprint(unsigned long start, unsigned long size)
+
+is provided. The use should be self explanatory.
+
+Register and memory access functions are provided in helper_mem.c.
+The PIO register access functions can trap access to PCI config space
+access register (config method 1) if _PC is not defined.
+
+A header file 'defines.h' is required to define OS/emulator specific
+ways to access memory and xf86 CPU registers: Defines need to be
+provided for memory byte/work/long read/write access
+(MEM_RB(name,addr),MEM_RW(name,addr),MEM_RL(name,addr),
+MEM_WB(name,addr,val),MEM_WL(name,addr,val),MEM_WL(name,addr,val)) of
+the real mode memory environment. 'name' will contain a pointer to the
+current xf86Int10InfoRec. Currently defines are available for
+vm86-mode under Linux and x86emu. They may be activated by defining
+_X86EMU or _VM86_LINUX respectively.
+
+Note: Emulators usually are not able to pass this pointer when calling
+memory access functions. In this case a global variable should be
+defined which can hold this pointer. This variable can be set in
+MapCurrentInt10(). It also must be set in xf86InitInt10() if this
+function calls the memory access functions either directly or by
+calling xf86ExecX86int10(pInt). Defines to access the emulator
+specific xf86 CPU register locations are also required:
+X86_EAX,...,X86_EFLAGS for access of the full 32 bit registers,
+X86_AX...X86_FLAGS for access of the 16 bit registers and
+XF86_AL,XF86_BL,XF86_CL,XF86_DL to access the lower byte of the
+AX,BX,CX and DX register.
+
+
+$XFree86: xc/programs/Xserver/hw/xfree86/int10/INT10.HOWTO,v 1.2 2000/02/08 13:13:22 eich Exp $
|