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-rw-r--r--qemu/roms/openbios/arch/amd64/switch.S116
1 files changed, 0 insertions, 116 deletions
diff --git a/qemu/roms/openbios/arch/amd64/switch.S b/qemu/roms/openbios/arch/amd64/switch.S
deleted file mode 100644
index 66668150d..000000000
--- a/qemu/roms/openbios/arch/amd64/switch.S
+++ /dev/null
@@ -1,116 +0,0 @@
- .globl entry, __switch_context, __exit_context, halt
-
- .text
- .align 4
-
-/*
- * Entry point
- * We start execution from here.
- * It is assumed that CPU is in 32-bit protected mode and
- * all segments are 4GB and base zero (flat model).
- */
-entry:
- /* Save boot context and switch to our main context.
- * Main context is statically defined in C.
- */
- pushl %cs
- call __switch_context
-
- /* We get here when the main context switches back to
- * the boot context.
- * Return to previous bootloader.
- */
- ret
-
-/*
- * Switch execution context
- * This saves registers, segments, and GDT in the stack, then
- * switches the stack, and restores everything from the new stack.
- * This function takes no argument. New stack pointer is
- * taken from global variable __context, and old stack pointer
- * is also saved to __context. This way we can just jump to
- * this routine to get back to the original context.
- *
- * Call this routine with lcall or pushl %cs; call.
- */
-__switch_context:
- /* Save everything in current stack */
- pushfl /* 56 */
- pushl %ds /* 52 */
- pushl %es /* 48 */
- pushl %fs /* 44 */
- pushl %gs /* 40 */
- pushal /* 8 */
- subl $8, %esp
- movw %ss, (%esp) /* 0 */
- sgdt 2(%esp) /* 2 */
-
-#if 0
- /* Swap %cs and %eip on the stack, so lret will work */
- movl 60(%esp), %eax
- xchgl %eax, 64(%esp)
- movl %eax, 60(%esp)
-#endif
-
- /* At this point we don't know if we are on flat segment
- * or relocated. So compute the address offset from %eip.
- * Assuming CS.base==DS.base==SS.base.
- */
- call 1f
-1: popl %ebx
- subl $1b, %ebx
-
- /* Interrupts are not allowed... */
- cli
-
- /* Current context pointer is our stack pointer */
- movl %esp, %esi
-
- /* Normalize the ctx pointer */
- subl %ebx, %esi
-
- /* Swap it with new value */
- xchgl %esi, __context(%ebx)
-
- /* Adjust new ctx pointer for current address offset */
- addl %ebx, %esi
-
- /* Load new %ss and %esp to temporary */
- movzwl (%esi), %edx
- movl 20(%esi), %eax
-
- /* Load new GDT */
- lgdt 2(%esi)
-
- /* Load new stack segment with new GDT */
- movl %edx, %ss
-
- /* Set new stack pointer, but we have to adjust it because
- * pushal saves %esp value before pushal, and we want the value
- * after pushal.
- */
- leal -32(%eax), %esp
-
- /* Load the rest from new stack */
- popal
- popl %gs
- popl %fs
- popl %es
- popl %ds
- popfl
-
- /* Finally, load new %cs and %eip */
- lret
-
-__exit_context:
- /* Get back to the original context */
- pushl %cs
- call __switch_context
-
- /* We get here if the other context attempt to switch to this
- * dead context. This should not happen. */
-
-halt:
- cli
- hlt
- jmp halt