Add a serial console capable version of the FreeBSD boot manager. This has
been lying around my tree(s) for the past year or so. It could do with TLC. Requested by: obrien Sponsored by: Weyland-Yutani Corporation
This commit is contained in:
Bruce M Simpson
parent
aaf8327b2d
commit
49bce9d435
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=123301
@ -31,6 +31,14 @@ boot0.o: boot0.s
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${AS} ${AFLAGS} --defsym FLAGS=${BOOT_BOOT0_FLAGS} \
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--defsym TICKS=${BOOT_BOOT0_TICKS} ${.IMPSRC} -o ${.TARGET}
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CLEANFILES+= boot0.out boot0.o
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boot0sio: boot0sio.o
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${LD} -N -e start -Ttext ${BOOT_BOOT0_ORG} -o boot0sio.out boot0sio.o
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objcopy -S -O binary boot0sio.out ${.TARGET}
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boot0sio.o: boot0sio.s
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${AS} ${AFLAGS} --defsym FLAGS=${BOOT_BOOT0_FLAGS} \
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--defsym TICKS=${BOOT_BOOT0_TICKS} ${.IMPSRC} -o ${.TARGET}
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CLEANFILES+= boot0.out boot0.o boot0sio.out boot0sio.o
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.include <bsd.prog.mk>
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437
sys/boot/i386/boot0/boot0.S
Normal file
437
sys/boot/i386/boot0/boot0.S
Normal file
@ -0,0 +1,437 @@
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#
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# Copyright (c) 2002 Bruce M. Simpson
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# Copyright (c) 1998 Robert Nordier
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms are freely
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# permitted provided that the above copyright notice and this
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# paragraph and the following disclaimer are duplicated in all
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# such forms.
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#
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# This software is provided "AS IS" and without any express or
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# implied warranties, including, without limitation, the implied
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# warranties of merchantability and fitness for a particular
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# purpose.
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#
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# $FreeBSD$
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# A 512-byte boot manager which uses a 9600 baud serial console on COM1.
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.set NHRDRV,0x475 # Number of hard drives
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.set ORIGIN,0x600 # Execution address
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.set FAKE,0x800 # Partition entry
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.set LOAD,0x7c00 # Load address
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.set PRT_OFF,0x1be # Partition table
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.set TBL0SZ,0x3 # Table 0 size
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.set TBL1SZ,0xc # Table 1 size
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.set MAGIC,0xaa55 # Magic: bootable
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.set B0MAGIC,0xbb66 # Identification
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.set KEY_ENTER,0x1c # Enter key scan code
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.set KEY_F1,0x3b # F1 key scan code
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.set ASCII_BEL,0x07 # ASCII code for <BEL>
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.set ASCII_CR,0x0D # ASCII code for <CR>
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.set ASCII_1,0x31 # ASCII code for '1'
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#
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# Addresses in the sector of embedded data values.
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# Accessed with negative offsets from the end of the relocated sector (%ebp).
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#
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.set _NXTDRV,-0x48 # Next drive
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.set _OPT,-0x47 # Default option
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.set _SETDRV,-0x46 # Drive to force
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.set _FLAGS,-0x45 # Flags
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.set _TICKS,-0x44 # Timeout ticks
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.set _FAKE,0x0 # Fake partition entry
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.set _MNUOPT,0xc # Menu options
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.globl start # Entry point
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.code16 # This runs in real mode
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#
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# Initialise segments and registers to known values.
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# segments start at 0.
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# The stack is immediately below the address we were loaded to.
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#
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start: cld # String ops inc
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xorw %ax,%ax # Zero
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movw %ax,%es # Address
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movw %ax,%ds # data
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movw %ax,%ss # Set up
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movw $LOAD,%sp # stack
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#
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# Copy this code to the address it was linked for
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#
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movw %sp,%si # Source
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movw $start,%di # Destination
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movw $0x100,%cx # Word count
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rep # Relocate
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movsw # code
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#
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# Set address for variable space beyond code, and clear it.
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# Notice that this is also used to point to the values embedded in the block,
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# by using negative offsets.
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#
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movw %di,%bp # Address variables
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movb $0x8,%cl # Words to clear
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rep # Zero
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stosw # them
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#
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# Relocate to the new copy of the code.
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#
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incb -0xe(%di) # Sector number
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jmp main-LOAD+ORIGIN # To relocated code
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#
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# Initialize the serial port.
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# Must save DX (contains drive number)
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#
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main: pushw %dx # Save
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xorw %dx,%dx # Port: COM1
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movb $0xE3,%al # 9600 8-N-1
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movb $0x00,%ah # BIOS: Set COM Port
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int $0x14 # Parameters
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popw %dx # Restore
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#
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# Check what flags were loaded with us, specifically, Use a predefined Drive.
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# If what the bios gives us is bad, use the '0' in the block instead, as well.
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#
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testb $0x20,_FLAGS(%bp) # Set number drive?
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jnz main.1 # Yes
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testb %dl,%dl # Drive number valid?
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js main.2 # Possibly (0x80 set)
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main.1: movb _SETDRV(%bp),%dl # Drive number to use
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#
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# Whatever we decided to use, now store it into the fake
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# partition entry that lives in the data space above us.
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#
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main.2: movb %dl,_FAKE(%bp) # Save drive number
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callw putn # To new line
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pushw %dx # Save drive number
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#
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# Start out with a pointer to the 4th byte of the first table entry
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# so that after 4 iterations it's beyond the end of the sector.
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# and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
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# (remember that the table starts 2 bytes earlier than you would expect
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# as the bootable flag is after it in the block)
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#
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movw $(partbl+0x4),%bx # Partition table (+4)
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xorw %dx,%dx # Item number
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#
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# Loop around on the partition table, printing values until we
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# pass a 256 byte boundary. The end of loop test is at main.5.
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#
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main.3: movb %ch,-0x4(%bx) # Zero active flag (ch == 0)
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btw %dx,_FLAGS(%bp) # Entry enabled?
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jnc main.5 # No
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#
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# If any of the entries in the table are
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# the same as the 'type' in the slice table entry,
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# then this is an empty or non bootable partition. Skip it.
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#
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movb (%bx),%al # Load type
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movw $tables,%di # Lookup tables
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movb $TBL0SZ,%cl # Number of entries
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repne # Exclude
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scasb # partition?
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je main.5 # Yes
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#
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# Now scan the table of known types
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#
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movb $TBL1SZ,%cl # Number of entries
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repne # Known
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scasb # type?
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jne main.4 # No
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#
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# If it matches get the matching element in the
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# next array. if it doesn't, we are already
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# pointing at its first element which points to a "?".
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#
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addw $TBL1SZ,%di # Adjust
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main.4: movb (%di),%cl # Partition
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addw %cx,%di # description
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callw putx # Display it
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main.5: incw %dx # Next item
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addb $0x10,%bl # Next entry
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jnc main.3 # Till done
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#
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# Passed a 256 byte boundary..
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# table is finished.
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# Add one to the drive number and check it is valid,
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#
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popw %ax # Drive number
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subb $0x80-0x1,%al # Does next
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cmpb NHRDRV,%al # drive exist? (from BIOS?)
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jb main.6 # Yes
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# If not then if there is only one drive,
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# Don't display drive as an option.
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#
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decw %ax # Already drive 0?
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jz main.7 # Yes
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# If it was illegal or we cycled through them,
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# then go back to drive 0.
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#
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xorb %al,%al # Drive 0
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#
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# Whatever drive we selected, make it an ascii digit and save it back
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# to the "next drive" location in the loaded block in case we
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# want to save it for next time.
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# This also is part of the printed drive string so add 0x80 to indicate
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# end of string.
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#
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main.6: addb $'0'|0x80,%al # Save next
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movb %al,_NXTDRV(%bp) # drive number
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movw $drive,%di # Display
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callw putx # item
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#
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# Now that we've printed the drive (if we needed to), display a prompt.
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#
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main.7: movw $prompt,%si # Display
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callw putstr # prompt
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movb _OPT(%bp),%dl # Display
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decw %si # default
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callw putkey # key
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main.7_1:
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xorb %ah,%ah # BIOS: Get
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int $0x1a # system time
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movw %dx,%si # Ticks when
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addw _TICKS(%bp),%si # timeout
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#
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# Check for a character on the serial port.
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#
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main.8: xorw %dx,%dx # Use COM1
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movb $0x03,%ah # BIOS: Read COM
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int $0x14 # Status
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testb $0x01,%ah # Check line status
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jnz main.11 # (bit 1 indicates input)
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xorb %ah,%ah # BIOS: Get
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int $0x1a # system time
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cmpw %si,%dx # Timeout?
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jb main.8 # No
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#
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# If timed out or defaulting, come here.
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#
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main.9: movb _OPT(%bp),%al # Load default
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jmp main.12 # Join common code
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#
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# User's last try was bad, beep in displeasure.
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# Since nothing was printed, just continue on as if the user
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# hadn't done anything. This gives the effect of the user getting a beep
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# for all bad keystrokes but no action until either the timeout
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# occurs or the user hits a good key.
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#
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main.10: movb $ASCII_BEL,%al # Signal
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callw putchr # error
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jmp main.7_1 # Go back
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#
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# Check the character we just got on the serial port.
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# If it's CR act as if timed out.
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#
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main.11: movb $0x02,%ah # BIOS: Receive
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int $0x14 # COM Byte
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cmpb $ASCII_CR,%al # Enter pressed?
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je main.9 # Yes
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#
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# Otherwise check if legal
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# If not ask again.
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#
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subb $ASCII_1,%al # Less '1' ascii character
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cmpb $0x4,%al # 1..5?
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ja main.10 # No
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#
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# We have a selection.
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# but if it's a bad selection go back to complain.
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# The bits in MNUOPT were set when the options were printed.
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# Anything not printed is not an option.
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#
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main.12: cbtw # Option
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btw %ax,_MNUOPT(%bp) # enabled?
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jnc main.10 # No
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#
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# Save the info in the original tables
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# for rewriting to the disk.
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#
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movb %al,_OPT(%bp) # Save option
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movw $FAKE,%si # Partition for write
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movb (%si),%dl # Drive number
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movw %si,%bx # Partition for read
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cmpb $0x4,%al # 5 pressed?
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pushf # Save
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je main.13 # Yes
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shlb $0x4,%al # Point to
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addw $partbl,%ax # selected
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xchgw %bx,%ax # partition
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movb $0x80,(%bx) # Flag active
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#
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# If not asked to do a write-back (flags 0x40) don't do one.
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#
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main.13: pushw %bx # Save
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testb $0x40,_FLAGS(%bp) # No updates?
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jnz main.14 # Yes
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movw $start,%bx # Data to write
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movb $0x3,%ah # Write sector
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callw intx13 # to disk
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main.14: popw %si # Restore
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popf # Restore
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#
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# If going to next drive, replace drive with selected one.
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# Remember to un-ascii it. Hey 0x80 is already set, cool!
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#
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jne main.15 # If not 5
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movb _NXTDRV(%bp),%dl # Next drive
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subb $'0',%dl # number XXX char val?
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#
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# load selected bootsector to the LOAD location in RAM.
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# If it fails to read or isn't marked bootable, treat it
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# as a bad selection.
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# XXX what does %si carry?
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#
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main.15: movw $LOAD,%bx # Address for read
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movb $0x2,%ah # Read sector
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callw intx13 # from disk
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jc main.10 # If error
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cmpw $MAGIC,0x1fe(%bx) # Bootable?
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jne main.10 # No
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pushw %si # Save
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movw $crlf,%si # Leave some
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callw puts # space
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popw %si # Restore
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jmp *%bx # Invoke bootstrap
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#
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# Display routines
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#
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putkey: movb $ASCII_1,%al # Prepare
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addb %dl,%al # digit
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jmp putstr.1 # Display the rest
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#
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# Display the option and note that it is a valid option.
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# That last point is a bit tricky..
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#
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putx: btsw %dx,_MNUOPT(%bp) # Enable menu option
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movw $item,%si # Display
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callw putkey # key
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movw %di,%si # Display the rest
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puts: callw putstr # Display string
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putn: movw $crlf,%si # To next line
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putstr: lodsb # Get byte
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testb $0x80,%al # End of string?
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jnz putstr.2 # Yes
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putstr.1: callw putchr # Display char
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jmp putstr # Continue
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putstr.2: andb $~0x80,%al # Clear MSB
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putchr: pushw %dx # Save
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xorw %dx,%dx # Use COM1
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xorw %cx,%cx # No timeout
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movb $0x01,%ah # BIOS: Send
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int $0x14 # Character
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popw %dx # Restore
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retw # To caller
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# One-sector disk I/O routine
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intx13: movb 0x1(%si),%dh # Load head
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movw 0x2(%si),%cx # Load cylinder:sector
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movb $0x1,%al # Sector count
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pushw %si # Save
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movw %sp,%di # Save
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testb $0x80,_FLAGS(%bp) # Use packet interface?
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jz intx13.1 # No
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pushl $0x0 # Set the
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pushl 0x8(%si) # LBA address
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pushw %es # Set the transfer
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pushw %bx # buffer address
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push $0x1 # Block count
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push $0x10 # Packet size
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movw %sp,%si # Packet pointer
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decw %ax # Verify off
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orb $0x40,%ah # Use disk packet
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intx13.1: int $0x13 # BIOS: Disk I/O
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movw %di,%sp # Restore
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popw %si # Restore
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retw # To caller
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# Menu strings
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item: .ascii " "; .byte ' '|0x80
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prompt: .ascii "\nDef:"; .byte ' '|0x80
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crlf: .ascii "\r"; .byte '\n'|0x80
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# Partition type tables
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tables:
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#
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# These entries identify invalid or NON BOOT types and partitions.
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#
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.byte 0x0, 0x5, 0xf
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#
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# These values indicate bootable types we know the names of
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#
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.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x63, 0x83
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.byte 0x9f, 0xa5, 0xa6, 0xa9
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#
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# These are offsets that match the known names above and point to the strings
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# that will be printed.
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#
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.byte os_misc-. # Unknown
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.byte os_dos-. # DOS
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.byte os_dos-. # DOS
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.byte os_dos-. # DOS
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.byte os_dos-. # Windows
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.byte os_dos-. # Windows
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.byte os_dos-. # Windows
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.byte os_unix-. # UNIX
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.byte os_linux-. # Linux
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.byte os_bsd-. # BSD/OS
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.byte os_freebsd-. # FreeBSD
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.byte os_bsd-. # OpenBSD
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.byte os_bsd-. # NetBSD
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#
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# And here are the strings themselves. 0x80 or'd into a byte indicates
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# the end of the string. (not so great for Russians but...)
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#
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os_misc: .ascii "?"; .byte '?'|0x80
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os_dos: .ascii "DO"; .byte 'S'|0x80
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os_unix: .ascii "UNI"; .byte 'X'|0x80
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os_linux: .ascii "Lnu"; .byte 'x'|0x80
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os_freebsd: .ascii "F"
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os_bsd: .ascii "BS"; .byte 'D'|0x80
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.org PRT_OFF-0xe,0x90
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.word B0MAGIC # Magic number
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#
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# These values are sometimes changed before writing back to the drive
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# Be especially careful that nxtdrv: must come after drive:, as it
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# is part of the same string.
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#
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drive: .ascii "Drive "
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nxtdrv: .byte 0x0 # Next drive number
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opt: .byte 0x0 # Option
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setdrv: .byte 0x80 # Drive to force
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flags: .byte FLAGS # Flags
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ticks: .word TICKS # Delay
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#
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# here is the 64 byte partition table that fdisk would fiddle with.
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#
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partbl: .fill 0x40,0x1,0x0 # Partition table
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.word MAGIC # Magic number
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437
sys/boot/i386/boot0/boot0sio.s
Normal file
437
sys/boot/i386/boot0/boot0sio.s
Normal file
@ -0,0 +1,437 @@
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||||
#
|
||||
# Copyright (c) 2002 Bruce M. Simpson
|
||||
# Copyright (c) 1998 Robert Nordier
|
||||
# All rights reserved.
|
||||
#
|
||||
# Redistribution and use in source and binary forms are freely
|
||||
# permitted provided that the above copyright notice and this
|
||||
# paragraph and the following disclaimer are duplicated in all
|
||||
# such forms.
|
||||
#
|
||||
# This software is provided "AS IS" and without any express or
|
||||
# implied warranties, including, without limitation, the implied
|
||||
# warranties of merchantability and fitness for a particular
|
||||
# purpose.
|
||||
#
|
||||
|
||||
# $FreeBSD$
|
||||
|
||||
# A 512-byte boot manager which uses a 9600 baud serial console on COM1.
|
||||
|
||||
.set NHRDRV,0x475 # Number of hard drives
|
||||
.set ORIGIN,0x600 # Execution address
|
||||
.set FAKE,0x800 # Partition entry
|
||||
.set LOAD,0x7c00 # Load address
|
||||
|
||||
.set PRT_OFF,0x1be # Partition table
|
||||
|
||||
.set TBL0SZ,0x3 # Table 0 size
|
||||
.set TBL1SZ,0xc # Table 1 size
|
||||
|
||||
.set MAGIC,0xaa55 # Magic: bootable
|
||||
.set B0MAGIC,0xbb66 # Identification
|
||||
|
||||
.set KEY_ENTER,0x1c # Enter key scan code
|
||||
.set KEY_F1,0x3b # F1 key scan code
|
||||
|
||||
.set ASCII_BEL,0x07 # ASCII code for <BEL>
|
||||
.set ASCII_CR,0x0D # ASCII code for <CR>
|
||||
.set ASCII_1,0x31 # ASCII code for '1'
|
||||
|
||||
#
|
||||
# Addresses in the sector of embedded data values.
|
||||
# Accessed with negative offsets from the end of the relocated sector (%ebp).
|
||||
#
|
||||
.set _NXTDRV,-0x48 # Next drive
|
||||
.set _OPT,-0x47 # Default option
|
||||
.set _SETDRV,-0x46 # Drive to force
|
||||
.set _FLAGS,-0x45 # Flags
|
||||
.set _TICKS,-0x44 # Timeout ticks
|
||||
.set _FAKE,0x0 # Fake partition entry
|
||||
.set _MNUOPT,0xc # Menu options
|
||||
|
||||
.globl start # Entry point
|
||||
.code16 # This runs in real mode
|
||||
|
||||
#
|
||||
# Initialise segments and registers to known values.
|
||||
# segments start at 0.
|
||||
# The stack is immediately below the address we were loaded to.
|
||||
#
|
||||
start: cld # String ops inc
|
||||
xorw %ax,%ax # Zero
|
||||
movw %ax,%es # Address
|
||||
movw %ax,%ds # data
|
||||
movw %ax,%ss # Set up
|
||||
movw $LOAD,%sp # stack
|
||||
|
||||
#
|
||||
# Copy this code to the address it was linked for
|
||||
#
|
||||
movw %sp,%si # Source
|
||||
movw $start,%di # Destination
|
||||
movw $0x100,%cx # Word count
|
||||
rep # Relocate
|
||||
movsw # code
|
||||
#
|
||||
# Set address for variable space beyond code, and clear it.
|
||||
# Notice that this is also used to point to the values embedded in the block,
|
||||
# by using negative offsets.
|
||||
#
|
||||
movw %di,%bp # Address variables
|
||||
movb $0x8,%cl # Words to clear
|
||||
rep # Zero
|
||||
stosw # them
|
||||
#
|
||||
# Relocate to the new copy of the code.
|
||||
#
|
||||
incb -0xe(%di) # Sector number
|
||||
jmp main-LOAD+ORIGIN # To relocated code
|
||||
|
||||
#
|
||||
# Initialize the serial port.
|
||||
# Must save DX (contains drive number)
|
||||
#
|
||||
main: pushw %dx # Save
|
||||
xorw %dx,%dx # Port: COM1
|
||||
movb $0xE3,%al # 9600 8-N-1
|
||||
movb $0x00,%ah # BIOS: Set COM Port
|
||||
int $0x14 # Parameters
|
||||
popw %dx # Restore
|
||||
#
|
||||
# Check what flags were loaded with us, specifically, Use a predefined Drive.
|
||||
# If what the bios gives us is bad, use the '0' in the block instead, as well.
|
||||
#
|
||||
testb $0x20,_FLAGS(%bp) # Set number drive?
|
||||
jnz main.1 # Yes
|
||||
testb %dl,%dl # Drive number valid?
|
||||
js main.2 # Possibly (0x80 set)
|
||||
main.1: movb _SETDRV(%bp),%dl # Drive number to use
|
||||
#
|
||||
# Whatever we decided to use, now store it into the fake
|
||||
# partition entry that lives in the data space above us.
|
||||
#
|
||||
main.2: movb %dl,_FAKE(%bp) # Save drive number
|
||||
callw putn # To new line
|
||||
pushw %dx # Save drive number
|
||||
#
|
||||
# Start out with a pointer to the 4th byte of the first table entry
|
||||
# so that after 4 iterations it's beyond the end of the sector.
|
||||
# and beyond a 256 byte boundary and has overflowed 8 bits (see next comment).
|
||||
# (remember that the table starts 2 bytes earlier than you would expect
|
||||
# as the bootable flag is after it in the block)
|
||||
#
|
||||
movw $(partbl+0x4),%bx # Partition table (+4)
|
||||
xorw %dx,%dx # Item number
|
||||
#
|
||||
# Loop around on the partition table, printing values until we
|
||||
# pass a 256 byte boundary. The end of loop test is at main.5.
|
||||
#
|
||||
main.3: movb %ch,-0x4(%bx) # Zero active flag (ch == 0)
|
||||
btw %dx,_FLAGS(%bp) # Entry enabled?
|
||||
jnc main.5 # No
|
||||
#
|
||||
# If any of the entries in the table are
|
||||
# the same as the 'type' in the slice table entry,
|
||||
# then this is an empty or non bootable partition. Skip it.
|
||||
#
|
||||
movb (%bx),%al # Load type
|
||||
movw $tables,%di # Lookup tables
|
||||
movb $TBL0SZ,%cl # Number of entries
|
||||
repne # Exclude
|
||||
scasb # partition?
|
||||
je main.5 # Yes
|
||||
#
|
||||
# Now scan the table of known types
|
||||
#
|
||||
movb $TBL1SZ,%cl # Number of entries
|
||||
repne # Known
|
||||
scasb # type?
|
||||
jne main.4 # No
|
||||
#
|
||||
# If it matches get the matching element in the
|
||||
# next array. if it doesn't, we are already
|
||||
# pointing at its first element which points to a "?".
|
||||
#
|
||||
addw $TBL1SZ,%di # Adjust
|
||||
main.4: movb (%di),%cl # Partition
|
||||
addw %cx,%di # description
|
||||
callw putx # Display it
|
||||
main.5: incw %dx # Next item
|
||||
addb $0x10,%bl # Next entry
|
||||
jnc main.3 # Till done
|
||||
#
|
||||
# Passed a 256 byte boundary..
|
||||
# table is finished.
|
||||
# Add one to the drive number and check it is valid,
|
||||
#
|
||||
popw %ax # Drive number
|
||||
subb $0x80-0x1,%al # Does next
|
||||
cmpb NHRDRV,%al # drive exist? (from BIOS?)
|
||||
jb main.6 # Yes
|
||||
# If not then if there is only one drive,
|
||||
# Don't display drive as an option.
|
||||
#
|
||||
decw %ax # Already drive 0?
|
||||
jz main.7 # Yes
|
||||
# If it was illegal or we cycled through them,
|
||||
# then go back to drive 0.
|
||||
#
|
||||
xorb %al,%al # Drive 0
|
||||
#
|
||||
# Whatever drive we selected, make it an ascii digit and save it back
|
||||
# to the "next drive" location in the loaded block in case we
|
||||
# want to save it for next time.
|
||||
# This also is part of the printed drive string so add 0x80 to indicate
|
||||
# end of string.
|
||||
#
|
||||
main.6: addb $'0'|0x80,%al # Save next
|
||||
movb %al,_NXTDRV(%bp) # drive number
|
||||
movw $drive,%di # Display
|
||||
callw putx # item
|
||||
#
|
||||
# Now that we've printed the drive (if we needed to), display a prompt.
|
||||
#
|
||||
main.7: movw $prompt,%si # Display
|
||||
callw putstr # prompt
|
||||
movb _OPT(%bp),%dl # Display
|
||||
decw %si # default
|
||||
callw putkey # key
|
||||
|
||||
main.7_1:
|
||||
xorb %ah,%ah # BIOS: Get
|
||||
int $0x1a # system time
|
||||
movw %dx,%si # Ticks when
|
||||
addw _TICKS(%bp),%si # timeout
|
||||
|
||||
#
|
||||
# Check for a character on the serial port.
|
||||
#
|
||||
|
||||
main.8: xorw %dx,%dx # Use COM1
|
||||
movb $0x03,%ah # BIOS: Read COM
|
||||
int $0x14 # Status
|
||||
testb $0x01,%ah # Check line status
|
||||
jnz main.11 # (bit 1 indicates input)
|
||||
|
||||
xorb %ah,%ah # BIOS: Get
|
||||
int $0x1a # system time
|
||||
cmpw %si,%dx # Timeout?
|
||||
jb main.8 # No
|
||||
|
||||
#
|
||||
# If timed out or defaulting, come here.
|
||||
#
|
||||
main.9: movb _OPT(%bp),%al # Load default
|
||||
jmp main.12 # Join common code
|
||||
#
|
||||
# User's last try was bad, beep in displeasure.
|
||||
# Since nothing was printed, just continue on as if the user
|
||||
# hadn't done anything. This gives the effect of the user getting a beep
|
||||
# for all bad keystrokes but no action until either the timeout
|
||||
# occurs or the user hits a good key.
|
||||
#
|
||||
main.10: movb $ASCII_BEL,%al # Signal
|
||||
callw putchr # error
|
||||
jmp main.7_1 # Go back
|
||||
#
|
||||
# Check the character we just got on the serial port.
|
||||
# If it's CR act as if timed out.
|
||||
#
|
||||
main.11: movb $0x02,%ah # BIOS: Receive
|
||||
int $0x14 # COM Byte
|
||||
|
||||
cmpb $ASCII_CR,%al # Enter pressed?
|
||||
je main.9 # Yes
|
||||
#
|
||||
# Otherwise check if legal
|
||||
# If not ask again.
|
||||
#
|
||||
subb $ASCII_1,%al # Less '1' ascii character
|
||||
cmpb $0x4,%al # 1..5?
|
||||
ja main.10 # No
|
||||
#
|
||||
# We have a selection.
|
||||
# but if it's a bad selection go back to complain.
|
||||
# The bits in MNUOPT were set when the options were printed.
|
||||
# Anything not printed is not an option.
|
||||
#
|
||||
main.12: cbtw # Option
|
||||
btw %ax,_MNUOPT(%bp) # enabled?
|
||||
jnc main.10 # No
|
||||
#
|
||||
# Save the info in the original tables
|
||||
# for rewriting to the disk.
|
||||
#
|
||||
movb %al,_OPT(%bp) # Save option
|
||||
movw $FAKE,%si # Partition for write
|
||||
movb (%si),%dl # Drive number
|
||||
movw %si,%bx # Partition for read
|
||||
cmpb $0x4,%al # 5 pressed?
|
||||
pushf # Save
|
||||
je main.13 # Yes
|
||||
shlb $0x4,%al # Point to
|
||||
addw $partbl,%ax # selected
|
||||
xchgw %bx,%ax # partition
|
||||
movb $0x80,(%bx) # Flag active
|
||||
#
|
||||
# If not asked to do a write-back (flags 0x40) don't do one.
|
||||
#
|
||||
main.13: pushw %bx # Save
|
||||
testb $0x40,_FLAGS(%bp) # No updates?
|
||||
jnz main.14 # Yes
|
||||
movw $start,%bx # Data to write
|
||||
movb $0x3,%ah # Write sector
|
||||
callw intx13 # to disk
|
||||
main.14: popw %si # Restore
|
||||
popf # Restore
|
||||
#
|
||||
# If going to next drive, replace drive with selected one.
|
||||
# Remember to un-ascii it. Hey 0x80 is already set, cool!
|
||||
#
|
||||
jne main.15 # If not 5
|
||||
movb _NXTDRV(%bp),%dl # Next drive
|
||||
subb $'0',%dl # number XXX char val?
|
||||
#
|
||||
# load selected bootsector to the LOAD location in RAM.
|
||||
# If it fails to read or isn't marked bootable, treat it
|
||||
# as a bad selection.
|
||||
# XXX what does %si carry?
|
||||
#
|
||||
main.15: movw $LOAD,%bx # Address for read
|
||||
movb $0x2,%ah # Read sector
|
||||
callw intx13 # from disk
|
||||
jc main.10 # If error
|
||||
cmpw $MAGIC,0x1fe(%bx) # Bootable?
|
||||
jne main.10 # No
|
||||
pushw %si # Save
|
||||
movw $crlf,%si # Leave some
|
||||
callw puts # space
|
||||
popw %si # Restore
|
||||
jmp *%bx # Invoke bootstrap
|
||||
#
|
||||
# Display routines
|
||||
#
|
||||
|
||||
putkey: movb $ASCII_1,%al # Prepare
|
||||
addb %dl,%al # digit
|
||||
jmp putstr.1 # Display the rest
|
||||
|
||||
#
|
||||
# Display the option and note that it is a valid option.
|
||||
# That last point is a bit tricky..
|
||||
#
|
||||
putx: btsw %dx,_MNUOPT(%bp) # Enable menu option
|
||||
movw $item,%si # Display
|
||||
callw putkey # key
|
||||
movw %di,%si # Display the rest
|
||||
|
||||
puts: callw putstr # Display string
|
||||
|
||||
putn: movw $crlf,%si # To next line
|
||||
|
||||
putstr: lodsb # Get byte
|
||||
testb $0x80,%al # End of string?
|
||||
jnz putstr.2 # Yes
|
||||
putstr.1: callw putchr # Display char
|
||||
jmp putstr # Continue
|
||||
putstr.2: andb $~0x80,%al # Clear MSB
|
||||
|
||||
putchr: pushw %dx # Save
|
||||
xorw %dx,%dx # Use COM1
|
||||
xorw %cx,%cx # No timeout
|
||||
movb $0x01,%ah # BIOS: Send
|
||||
int $0x14 # Character
|
||||
popw %dx # Restore
|
||||
retw # To caller
|
||||
|
||||
# One-sector disk I/O routine
|
||||
|
||||
intx13: movb 0x1(%si),%dh # Load head
|
||||
movw 0x2(%si),%cx # Load cylinder:sector
|
||||
movb $0x1,%al # Sector count
|
||||
pushw %si # Save
|
||||
movw %sp,%di # Save
|
||||
testb $0x80,_FLAGS(%bp) # Use packet interface?
|
||||
jz intx13.1 # No
|
||||
pushl $0x0 # Set the
|
||||
pushl 0x8(%si) # LBA address
|
||||
pushw %es # Set the transfer
|
||||
pushw %bx # buffer address
|
||||
push $0x1 # Block count
|
||||
push $0x10 # Packet size
|
||||
movw %sp,%si # Packet pointer
|
||||
decw %ax # Verify off
|
||||
orb $0x40,%ah # Use disk packet
|
||||
intx13.1: int $0x13 # BIOS: Disk I/O
|
||||
movw %di,%sp # Restore
|
||||
popw %si # Restore
|
||||
retw # To caller
|
||||
|
||||
# Menu strings
|
||||
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDef:"; .byte ' '|0x80
|
||||
crlf: .ascii "\r"; .byte '\n'|0x80
|
||||
|
||||
# Partition type tables
|
||||
|
||||
tables:
|
||||
#
|
||||
# These entries identify invalid or NON BOOT types and partitions.
|
||||
#
|
||||
.byte 0x0, 0x5, 0xf
|
||||
#
|
||||
# These values indicate bootable types we know the names of
|
||||
#
|
||||
.byte 0x1, 0x4, 0x6, 0xb, 0xc, 0xe, 0x63, 0x83
|
||||
.byte 0x9f, 0xa5, 0xa6, 0xa9
|
||||
#
|
||||
# These are offsets that match the known names above and point to the strings
|
||||
# that will be printed.
|
||||
#
|
||||
.byte os_misc-. # Unknown
|
||||
.byte os_dos-. # DOS
|
||||
.byte os_dos-. # DOS
|
||||
.byte os_dos-. # DOS
|
||||
.byte os_dos-. # Windows
|
||||
.byte os_dos-. # Windows
|
||||
.byte os_dos-. # Windows
|
||||
.byte os_unix-. # UNIX
|
||||
.byte os_linux-. # Linux
|
||||
.byte os_bsd-. # BSD/OS
|
||||
.byte os_freebsd-. # FreeBSD
|
||||
.byte os_bsd-. # OpenBSD
|
||||
.byte os_bsd-. # NetBSD
|
||||
#
|
||||
# And here are the strings themselves. 0x80 or'd into a byte indicates
|
||||
# the end of the string. (not so great for Russians but...)
|
||||
#
|
||||
os_misc: .ascii "?"; .byte '?'|0x80
|
||||
os_dos: .ascii "DO"; .byte 'S'|0x80
|
||||
os_unix: .ascii "UNI"; .byte 'X'|0x80
|
||||
os_linux: .ascii "Lnu"; .byte 'x'|0x80
|
||||
os_freebsd: .ascii "F"
|
||||
os_bsd: .ascii "BS"; .byte 'D'|0x80
|
||||
|
||||
.org PRT_OFF-0xe,0x90
|
||||
|
||||
.word B0MAGIC # Magic number
|
||||
|
||||
#
|
||||
# These values are sometimes changed before writing back to the drive
|
||||
# Be especially careful that nxtdrv: must come after drive:, as it
|
||||
# is part of the same string.
|
||||
#
|
||||
drive: .ascii "Drive "
|
||||
nxtdrv: .byte 0x0 # Next drive number
|
||||
opt: .byte 0x0 # Option
|
||||
setdrv: .byte 0x80 # Drive to force
|
||||
flags: .byte FLAGS # Flags
|
||||
ticks: .word TICKS # Delay
|
||||
|
||||
#
|
||||
# here is the 64 byte partition table that fdisk would fiddle with.
|
||||
#
|
||||
partbl: .fill 0x40,0x1,0x0 # Partition table
|
||||
.word MAGIC # Magic number
|
||||
Loading…
Reference in New Issue
Block a user