source: vbox/trunk/src/VBox/Devices/PC/Etherboot-src/arch/i386/Config@ 11982

# Config for i386 Etherboot
#
# Do not delete the tag OptionDescription and /OptionDescription
# It is used to automatically generate the documentation.
#
# @OptionDescrition@
#
#       BIOS interface options:
#
#       -DPCBIOS
#                       Compile in support for the normal pcbios
#       -DLINUXBIOS
#                       Compile in support for LinuxBIOS
#       -DBBS_BUT_NOT_PNP_COMPLIANT
#                       Some BIOSes claim to be PNP but they don't conform
#                       to the BBS spec which specifies that ES:DI must
#                       point to the string $PnP on entry. This option
#                       works around those. This option must be added to
#                       LCONFIG.
#       -DNO_DELAYED_INT
#                       Take control as soon as BIOS detects the ROM.
#                       Normally hooks onto INT18H or INT19H. Use only if you
#                       have a very non-conformant BIOS as it bypasses
#                       BIOS initialisation of devices. This only works for
#                       legacy ROMs, i.e. PCI_PNP_HEADER not defined.
#                       This option was formerly called NOINT19H.
#       -DBOOT_INT18H
#                       Etherboot normally hooks onto INT19H for legacy ROMs.
#                       You can choose to hook onto INT18H (BASIC interpreter
#                       entry point) instead. This entry point is used when
#                       all boot devices have been exhausted. This option must
#                       be added to LCONFIG.
#       -DCONFIG_PCI_DIRECT
#                       Define this for PCI BIOSes that do not implement
#                       BIOS32 or not correctly. Normally not needed.
#                       Only works for BIOSes of a certain era.
#       -DCONFIG_TSC_CURRTICKS
#                       Uses the processor time stamp counter instead of reading
#                       the BIOS time counter.  This allows Etherboot to work
#                       even without a BIOS.  This only works on late model
#                       486s and above.
#       -DCONFIG_NO_TIMER2
#                       Some systems do not have timer2 implemented.
#                       If you have a RTC this will allow you to roughly calibrate
#                       it using outb instructions.
#       -DIBM_L40
#                       This option uses the 0x92 method of controlling
#                       A20 instead of the traditional method of using the
#                       keyboard controller. An explanation of A20 is here:
#                       http://www.win.tue.nl/~aeb/linux/kbd/A20.html
#                       This occurs on MCA, EISA and some embedded boards,
#                       and sometimes with the Fast Gate A20 option on some
#                       BIOSes.
#                       Enable this only if you are sure of what you are doing.
#
#       Extended cpu options

#       -DCONFIG_X86_64 
#                       Compile in support for booting x86_64 64bit binaries.
#
#       PXE loader options:
#
#       -DPXELOADER_KEEP_ALL
#                       Prevent PXE loader (prefix) from unloading the
#                       PXE stack.  You will want to use this if, for
#                       example, you are booting via PXE-on-floppy.
#                       You may want to use it under certain
#                       circumstances when using the Etherboot UNDI
#                       driver; these are complex and best practice is
#                       not yet established.
#                       
#       Obscure options you probably don't need to touch:
#
#       -DIGNORE_E820_MAP
#                       Ignore the memory map returned by the E820 BIOS
#                       call.  May be necessary on some buggy BIOSes.
#       -DT503_AUI
#                       Use AUI by default on 3c503 cards.
#       -DFLATTEN_REAL_MODE
#                       Use 4GB segment limits when calling out to or
#                       returning to real-mode code.  This is necessary to
#                       work around some buggy code (e.g. OpenBSD's pxeboot)
#                       that uses flat real-mode without being sufficiently
#                       paranoid about the volatility of its segment limits.

#
# @/OptionDescription@

ifeq ($(ENVIRONMENT),VBOX)
EB_CFLAGS+=     -DPCBIOS
EB_CFLAGS+=     -fstrength-reduce -fomit-frame-pointer -march=i386
EB_CFLAGS+=     $(call VBOX_GCC32_CHECK_CC,-falign-jumps=1 -falign-loops=1 -falign-functions=1,\
                                           -malign-jumps=1 -malign-loops=1 -malign-functions=1)
EB_CFLAGS+=     $(call VBOX_GCC32_CHECK_CC,-mtune=i386,-mcpu=i386)
EB_LDFLAGS+=    -N
else # !VBOX
# BIOS select don't change unless you know what you are doing
CFLAGS+=        -DPCBIOS

# Compile in k8/hammer support
# CFLAGS+=      -DCONFIG_X86_64

# Options to make a version of Etherboot that will work under linuxBIOS.
# CFLAGS+=      -DLINUXBIOS -DCONFIG_TSC_CURRTICKS  -DCONSOLE_SERIAL -DCOMCONSOLE=0x3f8 -DCOMPRESERVE -DCONFIG_PCI_DIRECT -DELF_IMAGE 

# These options affect the loader that is prepended to the Etherboot image
# LCONFIG+=     -DBBS_BUT_NOT_PNP_COMPLIANT
# LCONFIG+=     -DBOOT_INT18H

# Produce code that will work inside the Bochs emulator.  The pnic
# driver is probably the best one to try.
# CFLAGS+=      -DCONFIG_PCI_DIRECT

# Produce code that will work with OpenBSD's pxeboot
# CFLAGS+=      -DFLATTEN_REAL_MODE

CFLAGS+= -fstrength-reduce -fomit-frame-pointer -march=i386
# Squeeze the code in as little space as possible.
# gcc3 needs a different syntax to gcc2 if you want to avoid spurious warnings.
GCC_VERSION      = $(subst ., ,$(shell $(CC) -dumpversion))
GCC_MAJORVERSION = $(firstword $(GCC_VERSION))
ifeq ($(GCC_MAJORVERSION),2)
CFLAGS+=        -malign-jumps=1 -malign-loops=1 -malign-functions=1
else
CFLAGS+=        -falign-jumps=1 -falign-loops=1 -falign-functions=1
endif
GCC_MINORVERSION = $(word 2, $(GCC_VERSION))
ifneq ($(GCC_MINORVERSION),4)
CFLAGS+=        -mcpu=i386
endif

LDFLAGS+=       -N

ifeq "$(shell uname -s)" "FreeBSD"
CFLAGS+=        -DIMAGE_FREEBSD -DELF_IMAGE -DAOUT_IMAGE
endif

# An alternate location for isolinux.bin can be set here
# ISOLINUX_BIN=/path/to/isolinux.bin
endif # !VBOX