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      1 /*	$NetBSD: getextmemx.c,v 1.12 2024/08/24 20:23:11 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997, 1999
      5  *	Matthias Drochner.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  *
     27  */
     28 
     29 /*
     30  * Try 2 more fancy BIOS calls to get the size of extended
     31  * memory besides the classical int15/88, take maximum.
     32  * needs lowlevel parts from biosmemx.S and biosmem.S
     33  */
     34 
     35 #include <lib/libsa/stand.h>
     36 #include "libi386.h"
     37 
     38 int
     39 getextmemx(void)
     40 {
     41 	/*
     42 	 * Allocate 6 words, not 5, to work around buggy firmware --
     43 	 * see comment on getmementry in biosmemx.S.
     44 	 */
     45 	int buf[6], i;
     46 	int extmem = getextmem1();
     47 #ifdef SUPPORT_PS2
     48 	struct {
     49 		uint16_t len;
     50 		uint32_t dta[8];
     51 		/* pad to 64 bytes - without this, machine would reset */
     52 		uint8_t __pad[30];
     53 	} __packed bufps2;
     54 #endif
     55 
     56 #ifdef DEBUG_MEMSIZE
     57 	printf("extmem1: %xk\n", extmem);
     58 #endif
     59 	if (!getextmem2(buf)) {
     60 #ifdef DEBUG_MEMSIZE
     61 		printf("extmem2: %xk + %xk\n", buf[0], buf[1] * 64);
     62 #endif
     63 		if (buf[0] <= 15 * 1024) {
     64 			int help = buf[0];
     65 			if (help == 15 * 1024)
     66 				help += buf[1] * 64;
     67 			if (extmem < help)
     68 				extmem = help;
     69 		}
     70 	}
     71 
     72 	i = 0;
     73 	do {
     74 		if (getmementry(&i, buf))
     75 			break;
     76 #ifdef DEBUG_MEMSIZE
     77 		printf("mementry: (%d) %x %x %x %x %x\n",
     78 			i, buf[0], buf[1], buf[2], buf[3], buf[4]);
     79 #endif
     80 		if ((buf[4] == 1 && buf[0] == 0x100000)
     81 		    && extmem < buf[2] / 1024)
     82 			extmem = buf[2] / 1024;
     83 	} while (i);
     84 
     85 #ifdef SUPPORT_PS2
     86 	/* use local memory information from RETURN MEMORY-MAP INFORMATION */
     87 	if (!getextmemps2((void *) &bufps2)) {
     88 		int help = bufps2.dta[0];
     89 		if (help == 15 * 1024)
     90 			help += bufps2.dta[1];
     91 		if (extmem < help)
     92 			extmem = help;
     93 	}
     94 #endif
     95 
     96 	return extmem;
     97 }
     98