| boot1.S (62660) | boot1.S (80751) |
|---|---|
| 1# 2# Copyright (c) 1998 Robert Nordier 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms are freely 6# permitted provided that the above copyright notice and this 7# paragraph and the following disclaimer are duplicated in all 8# such forms. 9# 10# This software is provided "AS IS" and without any express or 11# implied warranties, including, without limitation, the implied 12# warranties of merchantability and fitness for a particular 13# purpose. 14# 15 | 1# 2# Copyright (c) 1998 Robert Nordier 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms are freely 6# permitted provided that the above copyright notice and this 7# paragraph and the following disclaimer are duplicated in all 8# such forms. 9# 10# This software is provided "AS IS" and without any express or 11# implied warranties, including, without limitation, the implied 12# warranties of merchantability and fitness for a particular 13# purpose. 14# 15 |
| 16# $FreeBSD: head/sys/boot/i386/boot2/boot1.S 62660 2000-07-06 00:29:40Z jhb $ | 16# $FreeBSD: head/sys/boot/i386/boot2/boot1.S 80751 2001-07-31 19:50:09Z jhb $ |
| 17 18# Memory Locations 19 .set MEM_REL,0x700 # Relocation address 20 .set MEM_ARG,0x900 # Arguments 21 .set MEM_ORG,0x7c00 # Origin 22 .set MEM_BUF,0x8c00 # Load area 23 .set MEM_BTX,0x9000 # BTX start 24 .set MEM_JMP,0x9010 # BTX entry point --- 13 unchanged lines hidden (view full) --- 38 .set SIZ_SEC,0x200 # Sector size 39 40 .globl start 41 .globl xread 42 .code16 43 44start: jmp main # Start recognizably 45 | 17 18# Memory Locations 19 .set MEM_REL,0x700 # Relocation address 20 .set MEM_ARG,0x900 # Arguments 21 .set MEM_ORG,0x7c00 # Origin 22 .set MEM_BUF,0x8c00 # Load area 23 .set MEM_BTX,0x9000 # BTX start 24 .set MEM_JMP,0x9010 # BTX entry point --- 13 unchanged lines hidden (view full) --- 38 .set SIZ_SEC,0x200 # Sector size 39 40 .globl start 41 .globl xread 42 .code16 43 44start: jmp main # Start recognizably 45 |
| 46 .org 0x4,0x90 | 46# This is the start of a standard BIOS Parameter Block (BPB). Most bootable 47# FAT disks have this at the start of their MBR. While normal BIOS's will 48# work fine without this section, IBM's El Torito emulation "fixes" up the 49# BPB by writing into the memory copy of the MBR. Rather than have data 50# written into our xread routine, we'll define a BPB to work around it. 51# The data marked with (T) indicates a field required for a ThinkPad to 52# recognize the disk and (W) indicates fields written from IBM BIOS code. 53# The use of the BPB is based on what OpenBSD and NetBSD implemented in 54# their boot code but the required fields were determined by trial and error. 55# 56# Note: If additional space is needed in boot1, one solution would be to 57# move the "prompt" message data (below) to replace the OEM ID. 58 59 .org 0x03, 0x00 60oemid: .space 0x08, 0x00 # OEM ID 61 62 .org 0x0b, 0x00 63bpb: .word 512 # sector size (T) 64 .byte 0 # sectors/clustor 65 .word 0 # reserved sectors 66 .byte 0 # number of FATs 67 .word 0 # root entries 68 .word 0 # small sectors 69 .byte 0 # media type (W) 70 .word 0 # sectors/fat 71 .word 18 # sectors per track (T) 72 .word 2 # number of heads (T) 73 .long 0 # hidden sectors (W) 74 .long 0 # large sectors 75 76 .org 0x24, 0x00 77ebpb: .byte 0 # BIOS physical drive number (W) 78 79 .org 0x25,0x90 |
| 47# 48# Trampoline used by boot2 to call read to read data from the disk via 49# the BIOS. Call with: 50# 51# %cx:%ax - long - LBA to read in 52# %es:(%bx) - caddr_t - buffer to read data into 53# %dl - byte - drive to read from 54# %dh - byte - num sectors to read --- 273 unchanged lines hidden --- | 80# 81# Trampoline used by boot2 to call read to read data from the disk via 82# the BIOS. Call with: 83# 84# %cx:%ax - long - LBA to read in 85# %es:(%bx) - caddr_t - buffer to read data into 86# %dl - byte - drive to read from 87# %dh - byte - num sectors to read --- 273 unchanged lines hidden --- |