xfree86/int10/INT10.HOWTO

7 INT10 is  a XFree86  module for soft-booting  and executing  real mode
13 To   use   the   int10   module   in  a   driver   the   header   file
14 xfree86/os-support/int10/xf86int10.h must be included.
17  -----------------
19 The int10-executer gets initialized by calling:
23 The  function  will soft-boot  any  non-primary  device  and return  a
25 int10 execution  is disabled by an  option in the  device section NULL
29  b. Memory allocation
30  --------------------
32 To allocate memory in the real mode execution environment
37 returns the address of the allocated area. off is set to its offset in
38 the real mode memory space.
45  -------------------------
52 the ax, bx, cx, dx, si, di  and es x86-CPU registers can be set in the
57  d. De-initializing
58  -----------------
65 to free the memory allocated for real mode int10 calls.
72 CPU emulators as well as in vm86  mode of a real x86 CPU. If used with
94  to access memory  from the real mode memory  environment.  Note, that
95  the  vm86  mode  usually  requires  one hunk  of  consecutive  memory
96  starting at address  0 in the process virtual  memory space.  Thus if
98  that, ie. it must be able to remap the processes virtual memory space
99  onto itself.  If the  emulator is able  to handle memory  access thru
100  externally  provided functions the  real mode  process memory  can be
101  located anywhere  in the processes  virtual memory. It does  not even
110 part and an emulator specific one. A generic setup code is provided in
115 If the  vm86() is to be used  no memory access functions  can be used.
116 Therefore the layout of the real mode memory image has to meet certain
120 IPC to  map the  appropriate real  mode memory image  to address  0 in
121 virtual  address  space  just  prior  to execution  may  be  found  in
122 xfree86/os-support/linux/int10/linux.c.
124 On  non-PC like  platforms emulation  of certain  PC features  such as
129 -------------
131 This sets  up the real mode  memory image, calls the  emulator to POST
132 the chipset if required and  maintains memory allocations in real mode
146     a. int entityIndex   - index of the entity whose BIOS is to be
148     b. int scrnIndex     - index of the screen assigned the entity.
149     c. pointer cpuRegs   - pointer to a emulator/vm86-mode private
152     d. CARD16 BIOSseg    - Video BIOS segment address.
153     e. pointer private   - pointer to a os specific data structure.
154     f. struct _int10Mem* - pointer to a structure to hold the memory
156     g. int num           - number of the int to be called.
157     h. int ax..es,flags  - CPU register values to pass to int-call.
159 The Init  function should initialize  a-f. To initialize  the emulator
165 memory should be freed and xf86Int10Init(0 should exit returning NULL.
168 mapped into memory  locations SYS_BIOS to SYS_SIZE-1 of  the real mode
169 memory environment of this process. Otherwise the helper function:
175 corresponding to SYS_BIOS in the  real mode environment.  If a PC-like
177 LOW_PAGE_SIZE of the entities real mode environment.  In this case the
178 video interrupt  related entries should  be reset for  all non-primary
183 correct video BIOS  entry points the BIOS must  be warm-booted.  If no
184 PC-like int vector is available one can be set up by calling
188 In this  case the  video BIOS  has to be  warm-booted always.   If the
190 mapped (or  copied) directly to the  correct address in  the real mode
191 memory environment.  Otherwise
198 mapPciRom(). This function  will return the size of  the BIOS image in
204 may be called.  It sets up a 'hlt' instruction  in the emulator memory
207 to be  warm-booted this should be done  before leaving xf86InitInt10()
208 by setting num in the xf86Int10InfoRec to 0xe6 and calling
221 In case  a platform specific  mapping has to  be performed to  map the
222 memory allocated for the real  mode memory environment into a specific
229 that the 1MB real mode memory space located somewhere in the processes
230 virtual memory  will have to be  remapped to address 0  of the virtual
231 memory space.
235 To free all memory allocated for video BIOS calls of a specific entity
247 xf86Int10AllocPages()  should  allocate  'num'  consecutive  page-size
248 chunks of memory. In real mode memory space this range needs to occupy
250 this memory.  The offset in real  mode memory needs to  be returned in
260 -------------------------------
276 set up the non-static real mode execution environment.  On return from
298 trap.  PIO  access  is handled  by  the  in/out  calls as  defined  in
300 PRINT_PORT in xf86int10.h. This is meant for debugging purposes.
309 Functions to dump memory, code, xf86 CPU register values and stack are
310 also provided.  Take a  look at  helper.c To view  a memory  range the
317 Register  and memory  access functions  are provided  in helper_mem.c.
322 ways  to access  memory and  xf86 CPU  registers: Defines  need  to be
323 provided     for    memory     byte/work/long     read/write    access
326 the real mode memory environment. 'name' will contain a pointer to the
328 vm86-mode under  Linux and x86emu.  They may be activated  by defining
332 memory  access functions.  In this  case a  global variable  should be
333 defined  which can  hold this  pointer. This  variable can  be  set in
334 MapCurrentInt10().  It also  must be  set in  xf86InitInt10()  if this
335 function  calls the  memory  access functions  either  directly or  by