From f07a4c844da9f0ecae5bbee1ab94be56505f26f7 Mon Sep 17 00:00:00 2001
From: Thomas Bushnell <thomas@gnu.org>
Date: Tue, 25 Feb 1997 21:28:37 +0000
Subject: Initial source

---
 i386/pc/rv86/rv86_real_int_asm.S | 119 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 i386/pc/rv86/rv86_real_int_asm.S

(limited to 'i386/pc/rv86/rv86_real_int_asm.S')

diff --git a/i386/pc/rv86/rv86_real_int_asm.S b/i386/pc/rv86/rv86_real_int_asm.S
new file mode 100644
index 0000000..54b1b9b
--- /dev/null
+++ b/i386/pc/rv86/rv86_real_int_asm.S
@@ -0,0 +1,119 @@
+/* 
+ * Copyright (c) 1995 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/asm.h>
+#include <mach/machine/eflags.h>
+
+#include "trap.h"
+#include "i386_asm.h"
+#include "pc_asm.h"
+#include "trap_asm.h"
+
+	.text
+	.globl	rv86_real_int_asm
+rv86_real_int_asm:
+
+	/* Stash our protected-mode stack pointer.  */
+	movl	%esp,EXT(real_tss)+TSS_ESP0
+
+	/* Load the linear/physical-address data segment into ES,
+	   for easy access to real-mode memory.  */
+	movl	$LINEAR_DS,%edx
+	movw	%dx,%es
+
+	/* Find the physical address of the real-mode interrupt stack (es:ebx).
+	   A 6-byte stack frame has already been allocated on it.  */
+	movl	EXT(rv86_usp)+4,%ebx
+	shll	$4,%ebx
+	addl	EXT(rv86_usp),%ebx
+
+	/* Store the magic return pointer into the real-mode interrupt stack frame.  */
+	movl	EXT(rv86_rp),%edx
+	movl	%edx,%es:(%ebx)
+	movw	RCD_FLAGS(%eax),%dx
+	movw	%dx,%es:4(%ebx)
+
+	/* Find the address of the real mode interrupt vector (es:esi).  */
+	shll	$2,%esi
+
+	/* Build the v86 trap frame.  */
+	xorl	%edx,%edx
+	movw	RCD_GS(%eax),%dx
+	pushl	%edx
+	movw	RCD_FS(%eax),%dx
+	pushl	%edx
+	movw	RCD_DS(%eax),%dx
+	pushl	%edx
+	movw	RCD_ES(%eax),%dx
+	pushl	%edx
+	pushl	EXT(rv86_usp)+4
+	pushl	EXT(rv86_usp)
+	movl	$EFL_VM+EFL_IOPL_USER,%ecx
+	orw	RCD_FLAGS(%eax),%cx
+	andl	$-1-EFL_IF-EFL_TF,%ecx
+	pushl	%ecx
+	movw	%es:2(%esi),%edx
+	pushl	%edx
+	movw	%es:(%esi),%edx
+	pushl	%edx
+
+	/* Load the requested register state.  */
+	movl	RCD_EDI(%eax),%edi
+	movl	RCD_ESI(%eax),%esi
+	movl	RCD_EBP(%eax),%ebp
+	movl	RCD_EBX(%eax),%ebx
+	movl	RCD_EDX(%eax),%edx
+	movl	RCD_ECX(%eax),%ecx
+	movl	RCD_EAX(%eax),%eax
+
+	/* Drop into v86 mode.  */
+	iret
+
+ENTRY(rv86_return)
+
+	/* Restore the kernel segment registers.  */
+	movw	%ss,%ax
+	movw	%ax,%ds
+	movw	%ax,%es
+
+	/* Retrieve the real_call_data pointer from rv86_real_int_asm's stack frame.  */
+	movl	TR_V86SIZE+4(%esp),%eax
+
+	/* Stash the final register state.  */
+	movl	TR_EDI(%esp),%edx;	movl	%edx,RCD_EDI(%eax)
+	movl	TR_ESI(%esp),%edx;	movl	%edx,RCD_ESI(%eax)
+	movl	TR_EBP(%esp),%edx;	movl	%edx,RCD_EBP(%eax)
+	movl	TR_EBX(%esp),%edx;	movl	%edx,RCD_EBX(%eax)
+	movl	TR_EDX(%esp),%edx;	movl	%edx,RCD_EDX(%eax)
+	movl	TR_ECX(%esp),%edx;	movl	%edx,RCD_ECX(%eax)
+	movl	TR_EAX(%esp),%edx;	movl	%edx,RCD_EAX(%eax)
+	movl	TR_EFLAGS(%esp),%edx;	movw	%dx,RCD_FLAGS(%eax)
+	movl	TR_V86_ES(%esp),%edx;	movw	%dx,RCD_ES(%eax)
+	movl	TR_V86_DS(%esp),%edx;	movw	%dx,RCD_DS(%eax)
+	movl	TR_V86_FS(%esp),%edx;	movw	%dx,RCD_FS(%eax)
+	movl	TR_V86_GS(%esp),%edx;	movw	%dx,RCD_GS(%eax)
+
+	/* Return from the call to rv86_real_int_asm.  */
+	lea	TR_V86SIZE(%esp),%esp
+	ret
+
-- 
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