[prefix] Allow prefix to specify an arbitrary maximum address for relocation
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
parent
6c5f1a342b
commit
24226472b2
@ -42,7 +42,7 @@ extern char _etextdata[];
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*/
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__asmcall void relocate ( struct i386_all_regs *ix86 ) {
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struct memory_map memmap;
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unsigned long start, end, size, padded_size;
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unsigned long start, end, size, padded_size, max;
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unsigned long new_start, new_end;
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unsigned i;
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@ -57,6 +57,13 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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"...need %lx bytes for %d-byte alignment\n",
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start, end, padded_size, max_align );
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/* Determine maximum usable address */
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max = MAX_ADDR;
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if ( ix86->regs.ebp && ( ix86->regs.ebp < max ) ) {
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max = ix86->regs.ebp;
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DBG ( "Limiting relocation to [0,%lx)\n", max );
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}
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/* Walk through the memory map and find the highest address
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* below 4GB that iPXE will fit into.
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*/
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@ -67,18 +74,18 @@ __asmcall void relocate ( struct i386_all_regs *ix86 ) {
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DBG ( "Considering [%llx,%llx)\n", region->start, region->end);
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/* Truncate block to MAX_ADDR. This will be less than
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* 4GB, which means that we can get away with using
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* just 32-bit arithmetic after this stage.
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/* Truncate block to maximum address. This will be
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* less than 4GB, which means that we can get away
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* with using just 32-bit arithmetic after this stage.
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*/
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if ( region->start > MAX_ADDR ) {
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DBG ( "...starts after MAX_ADDR=%lx\n", MAX_ADDR );
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if ( region->start > max ) {
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DBG ( "...starts after max=%lx\n", max );
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continue;
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}
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r_start = region->start;
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if ( region->end > MAX_ADDR ) {
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DBG ( "...end truncated to MAX_ADDR=%lx\n", MAX_ADDR );
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r_end = MAX_ADDR;
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if ( region->end > max ) {
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DBG ( "...end truncated to max=%lx\n", max );
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r_end = max;
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} else {
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r_end = region->end;
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}
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@ -113,7 +113,7 @@ _exe_start:
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call alloc_basemem
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xorl %esi, %esi
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movl $EXE_DECOMPRESS_ADDRESS, %edi
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clc
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xorl %ebp, %ebp
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call install_prealloc
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/* Set up real-mode stack */
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@ -326,7 +326,6 @@ process_bytes:
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#ifndef KEEP_IT_REAL
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/* Preserve registers */
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pushfw
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pushl %eax
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pushl %ebp
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@ -397,7 +396,6 @@ process_bytes:
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/* Restore registers and return */
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popl %ebp
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popl %eax
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popfw
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ret
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#else /* KEEP_IT_REAL */
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@ -614,17 +612,19 @@ install:
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/* Preserve registers */
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pushl %esi
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pushl %edi
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pushl %ebp
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/* Allocate space for .text16 and .data16 */
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call alloc_basemem
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/* Image source = %cs:0000 */
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xorl %esi, %esi
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/* Image destination = default */
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xorl %edi, %edi
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/* Allow relocation */
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clc
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/* Allow arbitrary relocation */
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xorl %ebp, %ebp
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/* Install text and data segments */
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call install_prealloc
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/* Restore registers and return */
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popl %ebp
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popl %edi
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popl %esi
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ret
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@ -640,7 +640,7 @@ install:
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* %bx : .data16 segment address
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* %esi : Image source physical address (or zero for %cs:0000)
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* %edi : Decompression temporary area physical address (or zero for default)
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* CF set : Avoid relocating to top of memory
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* %ebp : Maximum end address for relocation (or zero for no maximum)
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* Corrupts:
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* none
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****************************************************************************
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@ -655,7 +655,6 @@ install_prealloc:
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pushw %ds
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pushw %es
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cld /* Sanity: clear the direction flag asap */
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pushfw
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/* Set up %ds for (read-only) access to .prefix */
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pushw %cs
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@ -791,11 +790,6 @@ payload_death_message:
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movw %ax, (init_librm_vector+2)
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lcall *init_librm_vector
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/* Skip relocation if CF was set on entry */
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popfw
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pushfw
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jc skip_relocate
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/* Call relocate() to determine target address for relocation.
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* relocate() will return with %esi, %edi and %ecx set up
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* ready for the copy to the new location.
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@ -818,7 +812,6 @@ payload_death_message:
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/* Initialise librm at new location */
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progress " init_librm\n"
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lcall *init_librm_vector
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skip_relocate:
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#endif
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/* Close access to payload */
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@ -827,7 +820,6 @@ skip_relocate:
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lcall *close_payload_vector
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/* Restore registers */
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popfw
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popw %es
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popw %ds
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popal
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@ -414,7 +414,7 @@ no_pmm:
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* picked up by the initial shell prompt, and we will drop
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* into a shell.
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*/
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stc /* Inhibit relocation */
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movl $0xa0000, %ebp /* Inhibit relocation during POST */
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pushw %cs
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call exec
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2:
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@ -614,7 +614,7 @@ decompress_to:
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* Called by the PnP BIOS when it wants to boot us.
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*/
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bev_entry:
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clc /* Allow relocation */
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xorl %ebp, %ebp /* Allow relocation */
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pushw %cs
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call exec
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lret
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@ -649,7 +649,7 @@ int19_entry:
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/* Leave keypress in buffer and start iPXE. The keypress will
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* cause the usual initial Ctrl-B prompt to be skipped.
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*/
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clc /* Allow relocation */
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xorl %ebp, %ebp /* Allow relocation */
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pushw %cs
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call exec
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1: /* Try to call original INT 19 vector */
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@ -681,9 +681,6 @@ exec: /* Set %ds = %cs */
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pushw %cs
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popw %ds
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/* Preserve state of CF */
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lahf
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/* Print message as soon as possible */
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movw $prodstr, %si
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xorw %di, %di
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@ -693,8 +690,8 @@ exec: /* Set %ds = %cs */
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/* Store magic word on BIOS stack and remember BIOS %ss:sp */
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pushl $STACK_MAGIC
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movw %ss, %dx
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movw %sp, %bp
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movw %ss, %cx
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movw %sp, %dx
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/* Obtain a reasonably-sized temporary stack */
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xorw %bx, %bx
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@ -702,10 +699,7 @@ exec: /* Set %ds = %cs */
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movw $0x7c00, %sp
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/* Install iPXE */
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sahf
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pushfw
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call alloc_basemem
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popfw
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movl image_source, %esi
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movl decompress_to, %edi
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call install_prealloc
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@ -728,14 +722,14 @@ exec: /* Set %ds = %cs */
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pushl $main
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pushw %cs
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call prot_call
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popl %ecx /* discard */
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popl %eax /* discard */
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/* Uninstall iPXE */
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call uninstall
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/* Restore BIOS stack */
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movw %dx, %ss
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movw %bp, %sp
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movw %cx, %ss
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movw %dx, %sp
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/* Check magic word on BIOS stack */
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popl %eax
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@ -14,6 +14,7 @@ undiloader:
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/* Save registers */
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pushl %esi
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pushl %edi
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pushl %ebp
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pushw %ds
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pushw %es
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pushw %bx
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@ -30,7 +31,7 @@ undiloader:
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movw %es:14(%di), %ax
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movl image_source, %esi
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movl decompress_to, %edi
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clc /* Allow relocation */
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xorl %ebp, %ebp /* Allow relocation */
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call install_prealloc
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popw %di
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/* Call UNDI loader C code */
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@ -46,6 +47,7 @@ undiloader:
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popw %bx
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popw %es
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popw %ds
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popl %ebp
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popl %edi
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popl %esi
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lret
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