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Diffstat (limited to 'sys/i386/boot/bios.s')
| -rw-r--r-- | sys/i386/boot/bios.s | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/sys/i386/boot/bios.s b/sys/i386/boot/bios.s new file mode 100644 index 000000000000..d1673a560042 --- /dev/null +++ b/sys/i386/boot/bios.s @@ -0,0 +1,326 @@ +/* + * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992 + * + * Mach Operating System + * Copyright (c) 1992, 1991 Carnegie Mellon University + * All Rights Reserved. + * + * Permission to use, copy, modify and distribute this software and its + * documentation is hereby granted, provided that both the copyright + * notice and this permission notice appear in all copies of the + * software, derivative works or modified versions, and any portions + * thereof, and that both notices appear in supporting documentation. + * + * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" + * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR + * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. + * + * Carnegie Mellon requests users of this software to return to + * + * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU + * School of Computer Science + * Carnegie Mellon University + * Pittsburgh PA 15213-3890 + * + * any improvements or extensions that they make and grant Carnegie Mellon + * the rights to redistribute these changes. + */ + +/* + * HISTORY + * $Log: bios.s,v $ + * Revision 2.2 92/04/04 11:34:26 rpd + * Fix Intel Copyright as per B. Davies authorization. + * [92/04/03 rvb] + * From 2.5 version + * [92/03/30 mg32] + * + * Revision 2.2 91/04/02 14:35:21 mbj + * Add Intel copyright + * [90/02/09 rvb] + * + */ + + +/* + Copyright 1988, 1989, 1990, 1991, 1992 + by Intel Corporation, Santa Clara, California. + + All Rights Reserved + +Permission to use, copy, modify, and distribute this software and +its documentation for any purpose and without fee is hereby +granted, provided that the above copyright notice appears in all +copies and that both the copyright notice and this permission notice +appear in supporting documentation, and that the name of Intel +not be used in advertising or publicity pertaining to distribution +of the software without specific, written prior permission. + +INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE +INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, +IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR +CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM +LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, +NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION +WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + + .file "bios.s" + +#include "asm.h" + .text + +/* +# biosread(dev, cyl, head, sec) +# Read one sector from disk into the internal buffer "intbuf" which +# is the first 512 bytes of the boot loader. +# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory +# Call with %ah = 0x2 +# %al = number of sectors +# %ch = cylinder +# %cl = sector +# %dh = head +# %dl = drive (0x80 for hard disk, 0x0 for floppy disk) +# %es:%bx = segment:offset of buffer +# Return: +# %al = 0x0 on success; err code on failure +*/ + +ENTRY(biosread) + push %ebp + mov %esp, %ebp + + push %ebx + push %ecx + push %edx + push %es + + movb 0x10(%ebp), %dh + movw 0x0c(%ebp), %cx + xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl + rorb $2, %cl + movb 0x14(%ebp), %al + orb %al, %cl + incb %cl # sector; sec starts from 1, not 0 + movb 0x8(%ebp), %dl # device + xor %ebx, %ebx # offset -- 0 + # prot_to_real will set %es to BOOTSEG + + call EXT(prot_to_real) # enter real mode + movb $0x2, %ah # subfunction + movb $0x1, %al # number of sectors -- one + + sti + int $0x13 + cli + + mov %eax, %ebx # save return value + + data16 + call EXT(real_to_prot) # back to protected mode + + xor %eax, %eax + movb %bh, %al # return value in %ax + + pop %es + pop %edx + pop %ecx + pop %ebx + pop %ebp + + ret + + +/* +# putc(ch) +# BIOS call "INT 10H Function 0Eh" to write character to console +# Call with %ah = 0x0e +# %al = character +# %bh = page +# %bl = foreground color ( graphics modes) +*/ + + +ENTRY(putc) + push %ebp + mov %esp, %ebp + push %ebx + push %ecx + + movb 0x8(%ebp), %cl + + call EXT(prot_to_real) + + data16 + mov $0x1, %ebx # %bh=0, %bl=1 (blue) + movb $0xe, %ah + movb %cl, %al + sti + int $0x10 # display a byte + cli + + data16 + call EXT(real_to_prot) + + pop %ecx + pop %ebx + pop %ebp + ret + + +/* +# getc() +# BIOS call "INT 16H Function 00H" to read character from keyboard +# Call with %ah = 0x0 +# Return: %ah = keyboard scan code +# %al = ASCII character +*/ + +ENTRY(getc) + push %ebp + mov %esp, %ebp + push %ebx # save %ebx + + call EXT(prot_to_real) + + movb $0x0, %ah + sti + int $0x16 + cli + + movb %al, %bl # real_to_prot uses %eax + + data16 + call EXT(real_to_prot) + + xor %eax, %eax + movb %bl, %al + + pop %ebx + pop %ebp + ret +/* +# ischar() +# if there is a character pending, return it; otherwise return 0 +# BIOS call "INT 16H Function 01H" to check whether a character is pending +# Call with %ah = 0x1 +# Return: +# If key waiting to be input: +# %ah = keyboard scan code +# %al = ASCII character +# Zero flag = clear +# else +# Zero flag = set +*/ +ENTRY(ischar) + push %ebp + mov %esp, %ebp + push %ebx + + call EXT(prot_to_real) # enter real mode + + xor %ebx, %ebx + movb $0x1, %ah + sti + int $0x16 + cli + data16 + jz nochar + movb %al, %bl + +nochar: + data16 + call EXT(real_to_prot) + + xor %eax, %eax + movb %bl, %al + + pop %ebx + pop %ebp + ret + +/* +# +# get_diskinfo(): return a word that represents the +# max number of sectors and heads and drives for this device +# +*/ + +ENTRY(get_diskinfo) + push %ebp + mov %esp, %ebp + push %es + push %ebx + push %ecx + push %edx + + movb 0x8(%ebp), %dl # diskinfo(drive #) + call EXT(prot_to_real) # enter real mode + + movb $0x8, %ah # ask for disk info + + sti + int $0x13 + cli + + data16 + call EXT(real_to_prot) # back to protected mode + + xor %eax, %eax + + /*form a longword representing all this gunk*/ + movb %dh, %ah # # heads + andb $0x3f, %cl # mask of cylinder gunk + movb %cl, %al # # sectors + + pop %edx + pop %ecx + pop %ebx + pop %es + pop %ebp + ret + +/* +# +# memsize(i) : return the memory size in KB. i == 0 for conventional memory, +# i == 1 for extended memory +# BIOS call "INT 12H" to get conventional memory size +# BIOS call "INT 15H, AH=88H" to get extended memory size +# Both have the return value in AX. +# +*/ + +ENTRY(memsize) + push %ebp + mov %esp, %ebp + push %ebx + + mov 8(%ebp), %ebx + + call EXT(prot_to_real) # enter real mode + + cmpb $0x1, %bl + data16 + je xext + + sti + int $0x12 + cli + data16 + jmp xdone + +xext: movb $0x88, %ah + sti + int $0x15 + cli + +xdone: + mov %eax, %ebx + + data16 + call EXT(real_to_prot) + + mov %ebx, %eax + pop %ebx + pop %ebp + ret |