328 lines
6.5 KiB
ArmAsm
328 lines
6.5 KiB
ArmAsm
/*
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* Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
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*
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* Mach Operating System
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* Copyright (c) 1992, 1991 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie Mellon
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* the rights to redistribute these changes.
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*/
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/*
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Copyright 1988, 1989, 1990, 1991, 1992
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by Intel Corporation, Santa Clara, California.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appears in all
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copies and that both the copyright notice and this permission notice
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appear in supporting documentation, and that the name of Intel
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not be used in advertising or publicity pertaining to distribution
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of the software without specific, written prior permission.
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INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
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IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
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CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
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NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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.file "bios.s"
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#include "asm.h"
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.text
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/*
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# biosread(dev, cyl, head, sec, nsec, offset)
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# Read "nsec" sectors from disk to offset "offset" in boot segment
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# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
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# Call with %ah = 0x2
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# %al = number of sectors
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# %ch = cylinder
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# %cl = sector
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# %dh = head
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# %dl = drive (0x80 for hard disk, 0x0 for floppy disk)
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# %es:%bx = segment:offset of buffer
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# Return:
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# %al = 0x0 on success; err code on failure
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*/
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ENTRY(biosread)
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push %ebp
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mov %esp, %ebp
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push %ebx
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push %ecx
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push %edx
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push %es
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movb 0x10(%ebp), %dh
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movw 0x0c(%ebp), %cx
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xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl
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rorb $2, %cl
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movb 0x14(%ebp), %al
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orb %al, %cl
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incb %cl # sector; sec starts from 1, not 0
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movb 0x8(%ebp), %dl # device
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movl 0x1c(%ebp), %ebx # offset
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# prot_to_real will set %es to BOOTSEG
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call EXT(prot_to_real) # enter real mode
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movb $0x2, %ah # subfunction
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addr32
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movb 0x18(%ebp), %al # number of sectors
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sti
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int $0x13
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cli
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mov %eax, %ebx # save return value (actually movw %ax, %bx)
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data32
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call EXT(real_to_prot) # back to protected mode
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xor %eax, %eax
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movb %bh, %al # return value in %ax
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pop %es
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pop %edx
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pop %ecx
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pop %ebx
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pop %ebp
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ret
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/*
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# putc(ch)
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# BIOS call "INT 10H Function 0Eh" to write character to console
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# Call with %ah = 0x0e
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# %al = character
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# %bh = page
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# %bl = foreground color ( graphics modes)
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*/
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ENTRY(putc)
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push %ebp
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mov %esp, %ebp
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push %ebx
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push %ecx
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movb 0x8(%ebp), %cl
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call EXT(prot_to_real)
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data32
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mov $0x1, %ebx # %bh=0, %bl=1 (blue)
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movb $0xe, %ah
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movb %cl, %al
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sti
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int $0x10 # display a byte
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cli
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data32
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call EXT(real_to_prot)
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pop %ecx
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pop %ebx
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pop %ebp
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ret
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/*
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# getc()
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# BIOS call "INT 16H Function 00H" to read character from keyboard
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# Call with %ah = 0x0
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# Return: %ah = keyboard scan code
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# %al = ASCII character
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*/
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ENTRY(getc)
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push %ebp
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mov %esp, %ebp
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push %ebx # save %ebx
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call EXT(prot_to_real)
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movb $0x0, %ah
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sti
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int $0x16
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cli
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movb %al, %bl # real_to_prot uses %eax
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data32
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call EXT(real_to_prot)
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xor %eax, %eax
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movb %bl, %al
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pop %ebx
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pop %ebp
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ret
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/*
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# ischar()
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# if there is a character pending, return it; otherwise return 0
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# BIOS call "INT 16H Function 01H" to check whether a character is pending
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# Call with %ah = 0x1
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# Return:
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# If key waiting to be input:
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# %ah = keyboard scan code
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# %al = ASCII character
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# Zero flag = clear
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# else
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# Zero flag = set
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*/
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ENTRY(ischar)
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push %ebp
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mov %esp, %ebp
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push %ebx
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call EXT(prot_to_real) # enter real mode
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xor %ebx, %ebx
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movb $0x1, %ah
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sti
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int $0x16
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cli
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data32
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jz nochar
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movb %al, %bl
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nochar:
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data32
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call EXT(real_to_prot)
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xor %eax, %eax
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movb %bl, %al
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pop %ebx
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pop %ebp
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ret
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/*
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#
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# get_diskinfo(): return a word that represents the
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# max number of sectors and heads and drives for this device
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#
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*/
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ENTRY(get_diskinfo)
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push %ebp
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mov %esp, %ebp
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push %es
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push %ebx
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push %ecx
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push %edx
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movb 0x8(%ebp), %dl # diskinfo(drive #)
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call EXT(prot_to_real) # enter real mode
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movb $0x8, %ah # ask for disk info
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sti
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int $0x13
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cli
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jnc ok
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/*
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* Urk. Call failed. It is not supported for floppies by old BIOS's.
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* Guess it's a 15-sector floppy. Initialize all the registers for
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* documentation, although we only need head and sector counts.
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*/
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subb %ah, %ah # %ax = 0
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movb %ah, %bh # %bh = 0
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movb $2, %bl # %bl bits 0-3 = drive type, 2 = 1.2M
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movb $79, %ch # max track
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movb $15, %cl # max sector
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movb $1, %dh # max head
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movb $1, %dl # # floppy drives installed
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# es:di = parameter table
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# carry = 0
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ok:
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data32
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call EXT(real_to_prot) # back to protected mode
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xor %eax, %eax
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/*form a longword representing all this gunk*/
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movb %dh, %ah # max head
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andb $0x3f, %cl # mask of cylinder gunk
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movb %cl, %al # max sector (and # sectors)
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pop %edx
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pop %ecx
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pop %ebx
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pop %es
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pop %ebp
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ret
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/*
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#
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# memsize(i) : return the memory size in KB. i == 0 for conventional memory,
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# i == 1 for extended memory
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# BIOS call "INT 12H" to get conventional memory size
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# BIOS call "INT 15H, AH=88H" to get extended memory size
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# Both have the return value in AX.
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#
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*/
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ENTRY(memsize)
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push %ebp
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mov %esp, %ebp
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push %ebx
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mov 8(%ebp), %ebx
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call EXT(prot_to_real) # enter real mode
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testb %bl, %bl
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data32
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jnz xext
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sti
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int $0x12
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cli
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data32
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jmp xdone
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xext: movb $0x88, %ah
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sti
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int $0x15
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cli
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xdone:
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mov %eax, %ebx
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data32
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call EXT(real_to_prot)
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mov %ebx, %eax
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pop %ebx
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pop %ebp
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ret
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