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/*
* Copyright (c) 1995-1994 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/code16.h>
#include <mach/machine/vm_types.h>
#include <mach/machine/far_ptr.h>
#include <mach/machine/asm.h>
#include "i16_a20.h"
#include "phys_mem.h"
#include "debug.h"
struct far_pointer_16 xms_control;
#define CALL_XMS "lcallw "SEXT(xms_control)
static vm_offset_t xms_phys_free_mem;
static vm_size_t xms_phys_free_size;
static short free_handle;
static char free_handle_allocated;
static char free_handle_locked;
CODE32
void xms_mem_collect(void)
{
if (xms_phys_free_mem)
{
phys_mem_add(xms_phys_free_mem, xms_phys_free_size);
xms_phys_free_mem = 0;
}
}
CODE16
static void i16_xms_enable_a20(void)
{
short success;
asm volatile(CALL_XMS : "=a" (success) : "a" (0x0500) : "ebx");
if (!success)
i16_die("XMS error: can't enable A20 line");
}
static void i16_xms_disable_a20(void)
{
short success;
asm volatile(CALL_XMS : "=a" (success) : "a" (0x0600) : "ebx");
if (!success)
i16_die("XMS error: can't disable A20 line");
}
void i16_xms_check()
{
unsigned short rc;
unsigned short free_k;
/* Check for an XMS server. */
asm volatile("
int $0x2f
" : "=a" (rc)
: "a" (0x4300));
if ((rc & 0xff) != 0x80)
return;
/* Get XMS driver's control function. */
asm volatile("
pushl %%ds
pushl %%es
int $0x2f
movw %%es,%0
popl %%es
popl %%ds
" : "=r" (xms_control.seg), "=b" (xms_control.ofs)
: "a" (0x4310));
/* See how much memory is available. */
asm volatile(CALL_XMS
: "=a" (free_k)
: "a" (0x0800)
: "ebx", "edx");
if (free_k * 1024 == 0)
return;
xms_phys_free_size = (unsigned)free_k * 1024;
/* Grab the biggest memory block we can get. */
asm volatile(CALL_XMS
: "=a" (rc), "=d" (free_handle)
: "a" (0x0900), "d" (free_k)
: "ebx");
if (!rc)
i16_die("XMS error: can't allocate extended memory");
free_handle_allocated = 1;
/* Lock it down. */
asm volatile(CALL_XMS "
shll $16,%%edx
movw %%bx,%%dx
" : "=a" (rc), "=d" (xms_phys_free_mem)
: "a" (0x0c00), "d" (free_handle)
: "ebx");
if (!rc)
i16_die("XMS error: can't lock down extended memory");
free_handle_locked = 1;
/* We need to update phys_mem_max here
instead of just letting phys_mem_add() do it
when the memory is collected with phys_mem_collect(),
because VCPI initialization needs to know the top of physical memory
before phys_mem_collect() is called.
See i16_vcpi.c for the gross details. */
if (phys_mem_max < xms_phys_free_mem + xms_phys_free_size)
phys_mem_max = xms_phys_free_mem + xms_phys_free_size;
i16_enable_a20 = i16_xms_enable_a20;
i16_disable_a20 = i16_xms_disable_a20;
do_debug(i16_puts("XMS detected"));
}
void i16_xms_shutdown()
{
unsigned short rc;
if (free_handle_locked)
{
/* Unlock our memory block. */
asm volatile(CALL_XMS
: "=a" (rc)
: "a" (0x0d00), "d" (free_handle)
: "ebx");
free_handle_locked = 0;
if (!rc)
i16_die("XMS error: can't unlock extended memory");
}
if (free_handle_allocated)
{
/* Free the memory block. */
asm volatile(CALL_XMS
: "=a" (rc)
: "a" (0x0a00), "d" (free_handle)
: "ebx");
free_handle_allocated = 0;
if (!rc)
i16_die("XMS error: can't free extended memory");
}
}
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