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1.1 root 1: /*
2: * Ported to boot 386BSD by Julian Elischer ([email protected]) Sept 1992
3: *
4: * Mach Operating System
5: * Copyright (c) 1992, 1991 Carnegie Mellon University
6: * All Rights Reserved.
7: *
8: * Permission to use, copy, modify and distribute this software and its
9: * documentation is hereby granted, provided that both the copyright
10: * notice and this permission notice appear in all copies of the
11: * software, derivative works or modified versions, and any portions
12: * thereof, and that both notices appear in supporting documentation.
13: *
14: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17: *
18: * Carnegie Mellon requests users of this software to return to
19: *
20: * Software Distribution Coordinator or [email protected]
21: * School of Computer Science
22: * Carnegie Mellon University
23: * Pittsburgh PA 15213-3890
24: *
25: * any improvements or extensions that they make and grant Carnegie Mellon
26: * the rights to redistribute these changes.
27: */
28:
29: /*
30: * HISTORY
1.1.1.2 ! root 31: * bios.S,v
! 32: Revision 1.2 1993/07/11 12:02:20 andrew
! 33: Fixes from bde, including support for loading @ any MB boundary (e.g. a
! 34: kernel linked for 0xfe100000 will load at the 1MB mark) and read-ahead
! 35: buffering to speed booting from floppies. Also works with aha174x
! 36: controllers in enhanced mode.
! 37:
! 38: *
! 39: * 93/06/28 bde
! 40: * Guess the disk size when the BIOS doesn't support the diskinfo
! 41: * interrupt.
! 42: *
! 43: * Change biosread() interface. Sector count and io address are now
! 44: * args.
1.1 root 45: *
1.1.1.2 ! root 46: * Change all data16's to data32's.
! 47: *
! 48: Revision 1.1 1993/03/21 18:08:23 cgd
! 49: after 0.2.2 "stable" patches applied
! 50:
1.1 root 51: * Revision 2.2 92/04/04 11:34:26 rpd
52: * Fix Intel Copyright as per B. Davies authorization.
53: * [92/04/03 rvb]
54: * From 2.5 version
55: * [92/03/30 mg32]
56: *
57: * Revision 2.2 91/04/02 14:35:21 mbj
58: * Add Intel copyright
59: * [90/02/09 rvb]
60: *
61: */
62:
63:
64: /*
65: Copyright 1988, 1989, 1990, 1991, 1992
66: by Intel Corporation, Santa Clara, California.
67:
68: All Rights Reserved
69:
70: Permission to use, copy, modify, and distribute this software and
71: its documentation for any purpose and without fee is hereby
72: granted, provided that the above copyright notice appears in all
73: copies and that both the copyright notice and this permission notice
74: appear in supporting documentation, and that the name of Intel
75: not be used in advertising or publicity pertaining to distribution
76: of the software without specific, written prior permission.
77:
78: INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
79: INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
80: IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
81: CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
82: LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
83: NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
84: WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
85: */
86:
87: .file "bios.s"
88:
89: #include "asm.h"
90: .text
91:
92: /*
1.1.1.2 ! root 93: # biosread(dev, cyl, head, sec, nsec, offset)
! 94: # Read "nsec" sectors from disk to offset "offset" in boot segment
1.1 root 95: # BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
96: # Call with %ah = 0x2
97: # %al = number of sectors
98: # %ch = cylinder
99: # %cl = sector
100: # %dh = head
101: # %dl = drive (0x80 for hard disk, 0x0 for floppy disk)
102: # %es:%bx = segment:offset of buffer
103: # Return:
104: # %al = 0x0 on success; err code on failure
105: */
106:
107: ENTRY(biosread)
108: push %ebp
109: mov %esp, %ebp
110:
111: push %ebx
112: push %ecx
113: push %edx
114: push %es
115:
116: movb 0x10(%ebp), %dh
117: movw 0x0c(%ebp), %cx
118: xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl
119: rorb $2, %cl
120: movb 0x14(%ebp), %al
121: orb %al, %cl
122: incb %cl # sector; sec starts from 1, not 0
123: movb 0x8(%ebp), %dl # device
1.1.1.2 ! root 124: movl 0x1c(%ebp), %ebx # offset
1.1 root 125: # prot_to_real will set %es to BOOTSEG
126:
127: call EXT(prot_to_real) # enter real mode
128: movb $0x2, %ah # subfunction
1.1.1.2 ! root 129: addr32
! 130: movb 0x18(%ebp), %al # number of sectors
1.1 root 131:
132: sti
133: int $0x13
134: cli
135:
1.1.1.2 ! root 136: mov %eax, %ebx # save return value (actually movw %ax, %bx)
1.1 root 137:
1.1.1.2 ! root 138: data32
1.1 root 139: call EXT(real_to_prot) # back to protected mode
140:
141: xor %eax, %eax
142: movb %bh, %al # return value in %ax
143:
144: pop %es
145: pop %edx
146: pop %ecx
147: pop %ebx
148: pop %ebp
149:
150: ret
151:
152:
153: /*
154: # putc(ch)
155: # BIOS call "INT 10H Function 0Eh" to write character to console
156: # Call with %ah = 0x0e
157: # %al = character
158: # %bh = page
159: # %bl = foreground color ( graphics modes)
160: */
161:
162:
163: ENTRY(putc)
164: push %ebp
165: mov %esp, %ebp
166: push %ebx
167: push %ecx
168:
169: movb 0x8(%ebp), %cl
170:
171: call EXT(prot_to_real)
172:
1.1.1.2 ! root 173: data32
1.1 root 174: mov $0x1, %ebx # %bh=0, %bl=1 (blue)
175: movb $0xe, %ah
176: movb %cl, %al
177: sti
178: int $0x10 # display a byte
179: cli
180:
1.1.1.2 ! root 181: data32
1.1 root 182: call EXT(real_to_prot)
183:
184: pop %ecx
185: pop %ebx
186: pop %ebp
187: ret
188:
189:
190: /*
191: # getc()
192: # BIOS call "INT 16H Function 00H" to read character from keyboard
193: # Call with %ah = 0x0
194: # Return: %ah = keyboard scan code
195: # %al = ASCII character
196: */
197:
198: ENTRY(getc)
199: push %ebp
200: mov %esp, %ebp
201: push %ebx # save %ebx
202:
203: call EXT(prot_to_real)
204:
205: movb $0x0, %ah
206: sti
207: int $0x16
208: cli
209:
210: movb %al, %bl # real_to_prot uses %eax
211:
1.1.1.2 ! root 212: data32
1.1 root 213: call EXT(real_to_prot)
214:
215: xor %eax, %eax
216: movb %bl, %al
217:
218: pop %ebx
219: pop %ebp
220: ret
221: /*
222: # ischar()
223: # if there is a character pending, return it; otherwise return 0
224: # BIOS call "INT 16H Function 01H" to check whether a character is pending
225: # Call with %ah = 0x1
226: # Return:
227: # If key waiting to be input:
228: # %ah = keyboard scan code
229: # %al = ASCII character
230: # Zero flag = clear
231: # else
232: # Zero flag = set
233: */
234: ENTRY(ischar)
235: push %ebp
236: mov %esp, %ebp
237: push %ebx
238:
239: call EXT(prot_to_real) # enter real mode
240:
241: xor %ebx, %ebx
242: movb $0x1, %ah
243: sti
244: int $0x16
245: cli
1.1.1.2 ! root 246: data32
1.1 root 247: jz nochar
248: movb %al, %bl
249:
250: nochar:
1.1.1.2 ! root 251: data32
1.1 root 252: call EXT(real_to_prot)
253:
254: xor %eax, %eax
255: movb %bl, %al
256:
257: pop %ebx
258: pop %ebp
259: ret
260:
261: /*
262: #
263: # get_diskinfo(): return a word that represents the
264: # max number of sectors and heads and drives for this device
265: #
266: */
267:
268: ENTRY(get_diskinfo)
269: push %ebp
270: mov %esp, %ebp
271: push %es
272: push %ebx
273: push %ecx
274: push %edx
275:
276: movb 0x8(%ebp), %dl # diskinfo(drive #)
277: call EXT(prot_to_real) # enter real mode
278:
279: movb $0x8, %ah # ask for disk info
280:
281: sti
282: int $0x13
283: cli
284:
1.1.1.2 ! root 285: jnc ok
! 286: /*
! 287: * Urk. Call failed. It is not supported for floppies by old BIOS's.
! 288: * Guess it's a 15-sector floppy. Initialize all the registers for
! 289: * documentation, although we only need head and sector counts.
! 290: */
! 291: subb %ah, %ah # %ax = 0
! 292: movb %al, %al
! 293: movb %ah, %bh # %bh = 0
! 294: movb $2, %bl # %bl bits 0-3 = drive type, 2 = 1.2M
! 295: movb $79, %ch # max track
! 296: movb $15, %cl # max sector
! 297: movb $1, %dh # max head
! 298: movb $1, %dl # # floppy drives installed
! 299: # es:di = parameter table
! 300: # carry = 0
! 301: ok:
! 302:
! 303: data32
1.1 root 304: call EXT(real_to_prot) # back to protected mode
305:
306: xor %eax, %eax
307:
308: /*form a longword representing all this gunk*/
1.1.1.2 ! root 309: movb %dh, %ah # max head
1.1 root 310: andb $0x3f, %cl # mask of cylinder gunk
1.1.1.2 ! root 311: movb %cl, %al # max sector (and # sectors)
1.1 root 312:
313: pop %edx
314: pop %ecx
315: pop %ebx
316: pop %es
317: pop %ebp
318: ret
319:
320: /*
321: #
322: # memsize(i) : return the memory size in KB. i == 0 for conventional memory,
323: # i == 1 for extended memory
324: # BIOS call "INT 12H" to get conventional memory size
325: # BIOS call "INT 15H, AH=88H" to get extended memory size
326: # Both have the return value in AX.
327: #
328: */
329:
330: ENTRY(memsize)
331: push %ebp
332: mov %esp, %ebp
333: push %ebx
334:
335: mov 8(%ebp), %ebx
336:
337: call EXT(prot_to_real) # enter real mode
338:
339: cmpb $0x1, %bl
1.1.1.2 ! root 340: data32
1.1 root 341: je xext
342:
343: sti
344: int $0x12
345: cli
1.1.1.2 ! root 346: data32
1.1 root 347: jmp xdone
348:
349: xext: movb $0x88, %ah
350: sti
351: int $0x15
352: cli
353:
354: xdone:
355: mov %eax, %ebx
356:
1.1.1.2 ! root 357: data32
1.1 root 358: call EXT(real_to_prot)
359:
360: mov %ebx, %eax
361: pop %ebx
362: pop %ebp
363: ret
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