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Annotation of Gnu-Mach/i386/dos/i16/i16_xms.c, revision 1.1

1.1     ! root        1: /* 
        !             2:  * Copyright (c) 1995-1994 The University of Utah and
        !             3:  * the Computer Systems Laboratory at the University of Utah (CSL).
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * Permission to use, copy, modify and distribute this software is hereby
        !             7:  * granted provided that (1) source code retains these copyright, permission,
        !             8:  * and disclaimer notices, and (2) redistributions including binaries
        !             9:  * reproduce the notices in supporting documentation, and (3) all advertising
        !            10:  * materials mentioning features or use of this software display the following
        !            11:  * acknowledgement: ``This product includes software developed by the
        !            12:  * Computer Systems Laboratory at the University of Utah.''
        !            13:  *
        !            14:  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
        !            15:  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
        !            16:  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            17:  *
        !            18:  * CSL requests users of this software to return to [email protected] any
        !            19:  * improvements that they make and grant CSL redistribution rights.
        !            20:  *
        !            21:  *      Author: Bryan Ford, University of Utah CSL
        !            22:  */
        !            23: 
        !            24: #include <mach/machine/code16.h>
        !            25: #include <mach/machine/vm_types.h>
        !            26: #include <mach/machine/far_ptr.h>
        !            27: #include <mach/machine/asm.h>
        !            28: 
        !            29: #include "i16_a20.h"
        !            30: #include "phys_mem.h"
        !            31: #include "debug.h"
        !            32: 
        !            33: 
        !            34: struct far_pointer_16 xms_control;
        !            35: 
        !            36: #define CALL_XMS "lcallw "SEXT(xms_control)
        !            37: 
        !            38: 
        !            39: static vm_offset_t xms_phys_free_mem;
        !            40: static vm_size_t xms_phys_free_size;
        !            41: 
        !            42: static short free_handle;
        !            43: static char free_handle_allocated;
        !            44: static char free_handle_locked;
        !            45: 
        !            46: 
        !            47: CODE32
        !            48: 
        !            49: void xms_mem_collect(void)
        !            50: {
        !            51:        if (xms_phys_free_mem)
        !            52:        {
        !            53:                phys_mem_add(xms_phys_free_mem, xms_phys_free_size);
        !            54:                xms_phys_free_mem = 0;
        !            55:        }
        !            56: }
        !            57: 
        !            58: CODE16
        !            59: 
        !            60: static void i16_xms_enable_a20(void)
        !            61: {
        !            62:        short success;
        !            63:        asm volatile(CALL_XMS : "=a" (success) : "a" (0x0500) : "ebx");
        !            64:        if (!success)
        !            65:                i16_die("XMS error: can't enable A20 line");
        !            66: }
        !            67: 
        !            68: static void i16_xms_disable_a20(void)
        !            69: {
        !            70:        short success;
        !            71:        asm volatile(CALL_XMS : "=a" (success) : "a" (0x0600) : "ebx");
        !            72:        if (!success)
        !            73:                i16_die("XMS error: can't disable A20 line");
        !            74: }
        !            75: 
        !            76: void i16_xms_check()
        !            77: {
        !            78:        unsigned short rc;
        !            79:        unsigned short free_k;
        !            80: 
        !            81:        /* Check for an XMS server.  */
        !            82:        asm volatile("
        !            83:                int $0x2f
        !            84:        " : "=a" (rc)
        !            85:          : "a" (0x4300));
        !            86:        if ((rc & 0xff) != 0x80)
        !            87:                return;
        !            88: 
        !            89:        /* Get XMS driver's control function.  */
        !            90:        asm volatile("
        !            91:                pushl   %%ds
        !            92:                pushl   %%es
        !            93:                int     $0x2f
        !            94:                movw    %%es,%0
        !            95:                popl    %%es
        !            96:                popl    %%ds
        !            97:        " : "=r" (xms_control.seg), "=b" (xms_control.ofs)
        !            98:          : "a" (0x4310));
        !            99: 
        !           100:        /* See how much memory is available.  */
        !           101:        asm volatile(CALL_XMS
        !           102:          : "=a" (free_k)
        !           103:          : "a" (0x0800)
        !           104:          : "ebx", "edx");
        !           105:        if (free_k * 1024 == 0)
        !           106:                return;
        !           107: 
        !           108:        xms_phys_free_size = (unsigned)free_k * 1024;
        !           109: 
        !           110:        /* Grab the biggest memory block we can get.  */
        !           111:        asm volatile(CALL_XMS
        !           112:          : "=a" (rc), "=d" (free_handle)
        !           113:          : "a" (0x0900), "d" (free_k)
        !           114:          : "ebx");
        !           115:        if (!rc)
        !           116:                i16_die("XMS error: can't allocate extended memory");
        !           117: 
        !           118:        free_handle_allocated = 1;
        !           119: 
        !           120:        /* Lock it down.  */
        !           121:        asm volatile(CALL_XMS "
        !           122:                shll    $16,%%edx
        !           123:                movw    %%bx,%%dx
        !           124:        " : "=a" (rc), "=d" (xms_phys_free_mem)
        !           125:          : "a" (0x0c00), "d" (free_handle)
        !           126:          : "ebx");
        !           127:        if (!rc)
        !           128:                i16_die("XMS error: can't lock down extended memory");
        !           129: 
        !           130:        free_handle_locked = 1;
        !           131: 
        !           132:        /* We need to update phys_mem_max here
        !           133:           instead of just letting phys_mem_add() do it
        !           134:           when the memory is collected with phys_mem_collect(),
        !           135:           because VCPI initialization needs to know the top of physical memory
        !           136:           before phys_mem_collect() is called.
        !           137:           See i16_vcpi.c for the gross details.  */
        !           138:        if (phys_mem_max < xms_phys_free_mem + xms_phys_free_size)
        !           139:                phys_mem_max = xms_phys_free_mem + xms_phys_free_size;
        !           140: 
        !           141:        i16_enable_a20 = i16_xms_enable_a20;
        !           142:        i16_disable_a20 = i16_xms_disable_a20;
        !           143: 
        !           144:        do_debug(i16_puts("XMS detected"));
        !           145: }
        !           146: 
        !           147: void i16_xms_shutdown()
        !           148: {
        !           149:        unsigned short rc;
        !           150: 
        !           151:        if (free_handle_locked)
        !           152:        {
        !           153:                /* Unlock our memory block.  */
        !           154:                asm volatile(CALL_XMS
        !           155:                  : "=a" (rc)
        !           156:                  : "a" (0x0d00), "d" (free_handle)
        !           157:                  : "ebx");
        !           158:                free_handle_locked = 0;
        !           159:                if (!rc)
        !           160:                        i16_die("XMS error: can't unlock extended memory");
        !           161:        }
        !           162: 
        !           163:        if (free_handle_allocated)
        !           164:        {
        !           165:                /* Free the memory block.  */
        !           166:                asm volatile(CALL_XMS
        !           167:                  : "=a" (rc)
        !           168:                  : "a" (0x0a00), "d" (free_handle)
        !           169:                  : "ebx");
        !           170:                free_handle_allocated = 0;
        !           171:                if (!rc)
        !           172:                        i16_die("XMS error: can't free extended memory");
        !           173:        }
        !           174: }
        !           175: 

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