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[prefix] Move flatten_real_mode to libflat.S

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2010-04-20 14:23:55 +01:00
parent d931d4bd9c
commit fb754ced56
2 changed files with 141 additions and 122 deletions
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122
src/arch/i386/prefix/libprefix.S
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@@ -41,8 +41,6 @@ FILE_LICENCE ( GPL2_OR_LATER )
/* Image compression enabled */
#define COMPRESS 1
#define CR0_PE 1
/*****************************************************************************
* Utility function: print character (with LF -> LF,CR translation)
*
@@ -232,126 +230,6 @@ print_kill_line:
ret
.size print_kill_line, . - print_kill_line
/****************************************************************************
* flatten_real_mode (real-mode far call)
*
* Set up 4GB segment limits
*
* Parameters:
* none
* Returns:
* none
* Corrupts:
* none
****************************************************************************
*/
#ifndef KEEP_IT_REAL
/* GDT for protected-mode calls */
.section ".text16.early.data", "aw", @progbits
.align 16
flatten_gdt:
flatten_gdt_limit: .word flatten_gdt_length - 1
flatten_gdt_base: .long 0
.word 0 /* padding */
flatten_cs: /* 16-bit protected-mode flat code segment */
.equ FLAT_CS, flatten_cs - flatten_gdt
.word 0xffff, 0
.byte 0, 0x9b, 0x8f, 0
flatten_ss: /* 16-bit protected-mode flat stack segment */
.equ FLAT_SS, flatten_ss - flatten_gdt
.word 0xffff, 0
.byte 0, 0x93, 0x8f, 0
flatten_gdt_end:
.equ flatten_gdt_length, . - flatten_gdt
.size flatten_gdt, . - flatten_gdt
.section ".text16.early.data", "aw", @progbits
.align 16
flatten_saved_gdt:
.long 0, 0
.size flatten_saved_gdt, . - flatten_saved_gdt
.section ".text16.early", "awx", @progbits
.code16
flatten_real_mode:
/* Preserve registers and flags */
pushfl
pushl %eax
pushw %si
pushw %gs
pushw %fs
pushw %es
pushw %ds
pushw %ss
/* Set %ds for access to .text16.early.data variables */
pushw %cs
popw %ds
/* Preserve original GDT */
sgdt flatten_saved_gdt
/* Set up GDT bases */
xorl %eax, %eax
movw %cs, %ax
shll $4, %eax
addl $flatten_gdt, %eax
movl %eax, flatten_gdt_base
movw %cs, %ax
movw $flatten_cs, %si
call set_seg_base
movw %ss, %ax
movw $flatten_ss, %si
call set_seg_base
/* Switch temporarily to protected mode and set segment registers */
pushw %cs
pushw $2f
cli
data32 lgdt flatten_gdt
movl %cr0, %eax
orb $CR0_PE, %al
movl %eax, %cr0
ljmp $FLAT_CS, $1f
1: movw $FLAT_SS, %ax
movw %ax, %ss
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
movl %cr0, %eax
andb $0!CR0_PE, %al
movl %eax, %cr0
lret
2: /* lret will ljmp to here */
/* Restore GDT, registers and flags */
data32 lgdt flatten_saved_gdt
popw %ss
popw %ds
popw %es
popw %fs
popw %gs
popw %si
popl %eax
popfl
lret
.size flatten_real_mode, . - flatten_real_mode
.section ".text16.early", "awx", @progbits
.code16
set_seg_base:
rolw $4, %ax
movw %ax, 2(%si)
andw $0xfff0, 2(%si)
movb %al, 4(%si)
andb $0x0f, 4(%si)
ret
.size set_seg_base, . - set_seg_base
#endif /* KEEP_IT_REAL */
/****************************************************************************
* copy_bytes
*