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Remove references to Simics in crt0.s comments

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Simics is not supported.

Change-Id: I2a1c7a3c6f19962f86a056b7628cd0d0fff6be1d
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>
This commit is contained in:
Peter Mitsis 2015-04-27 11:57:41 -04:00 • committed by Anas Nashif
commit d13eca21a5
1 changed files with 6 additions and 18 deletions
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24
arch/x86/bsp/crt0.s
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@ -35,23 +35,11 @@ This module contains the initial code executed by the VxMicro ELF image
after having been loaded into RAM.
INTERNAL
The CONFIG_PROT_MODE_SWITCH configuration option was once required when
booting/loading an image into a Simics simulation environment, since the
invocation technique involved halting the BIOS code (via a breakpoint) before
it attempted to load a bootloader from disk, and then dumping the VxMicro ELF
image into memory. This meant that the IA-32 processor was executing in 16-bit
real mode (aka real mode) when __start() was called, thus requiring __start()
to perform the 16-bit to 32-bit transition code and other sundry PC-related
initialization steps (eg. enabling address line A20).
Later advances now allow a VxMicro image to be loaded into the Simics environment
after the system is already in 32-bit protected mode and address line A20 is
enabled. Consequently, the CONFIG_PROT_MODE_SWITCH configuration option
is no longer used by this BSP, and *all* booting scenarios for the BSP (e.g.
via GRUB or any other multiboot compliant bootloader) now assume that the
system is already in 32-bit protected mode and address line A20 is enabled.
However, the code associated with CONFIG_PROT_MODE_SWITCH has been left
in place in case future booting scenarios arise which require its use.
The CONFIG_PROT_MODE_SWITCH configuration option is no longer used and *all*
booting scenarios (e.g. via GRUB or any other multiboot compliant bootloader)
now assume that the system is already in 32-bit protected mode and address line
A20 is enabled. However, the code associated with CONFIG_PROT_MODE_SWITCH has
been left in place should future booting scenarios arise which require its use.
*/
#define _ASMLANGUAGE
@ -287,7 +275,7 @@ SECTION_FUNC(TEXT_START, __start)
* registers are set correctly.
*
* This is a special case for the generic_pc BSP, which must work for
* multiple platforms (QEMU, SIMICS, generic PC board, etc.). With other
* multiple platforms (QEMU, generic PC board, etc.). With other
* BSPs the bootloader is well known so assumptions can be made.
*/
movw $0x10, %ax /* data segment selector (entry = 3) */