diff options
Diffstat (limited to 'i386/dos/i16/i16_xms.c')
| -rw-r--r-- | i386/dos/i16/i16_xms.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/i386/dos/i16/i16_xms.c b/i386/dos/i16/i16_xms.c new file mode 100644 index 0000000..ba75d5c --- /dev/null +++ b/i386/dos/i16/i16_xms.c @@ -0,0 +1,175 @@ +/* + * 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"); + } +} + |