mirror of
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- Properly merge boot0sio.s and boot0.s into boot0.S.
boot0sio.s was repo-copied to boot0.S. - Rename boot0ext.s to boot0ext.S, to stay consistent with other preprocessed asm files around here, and for better portability. Repocopied by: joe
This commit is contained in:
Ruslan Ermilov
parent
4fc21c0947
commit
69dd73b976
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=128722
@ -4,7 +4,7 @@ PROG= ${BOOT}
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INTERNALPROG=
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FILES= ${BOOT}
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NOMAN=
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SRCS= ${BOOT}.s
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SRCS= ${BOOT}.S
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BOOT?= boot0
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@ -29,18 +29,10 @@ BOOT_BOOT0_ORG?= 0x600
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# command line
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BOOT_BOOT0_COMCONSOLE_SPEED?= 0xE3
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AFLAGS+=--defsym FLAGS=${BOOT_BOOT0_FLAGS} \
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--defsym TICKS=${BOOT_BOOT0_TICKS} \
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--defsym COMSPEED=${BOOT_BOOT0_COMCONSOLE_SPEED}
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CFLAGS+=-DFLAGS=${BOOT_BOOT0_FLAGS} \
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-DTICKS=${BOOT_BOOT0_TICKS} \
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-DCOMSPEED=${BOOT_BOOT0_COMCONSOLE_SPEED}
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LDFLAGS=-N -e start -Ttext ${BOOT_BOOT0_ORG} -Wl,-S,--oformat,binary
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CLEANFILES+= boot0.s
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boot0.s: boot0_512.s
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cpp -USIO < ${.ALLSRC} > ${.TARGET}
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CLEANFILES+= boot0sio.s
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boot0sio.s: boot0_512.s
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cpp -DSIO < ${.ALLSRC} > ${.TARGET}
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.include <bsd.prog.mk>
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@ -1,4 +1,5 @@
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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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@ -12,46 +13,43 @@
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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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#
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# A 1024-byte boot manager.
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# A 512-byte boot manager.
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#ifdef SIO
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# ... using a serial console on COM1.
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#endif /* SIO */
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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 SECTOR_SIZE,0x200 # Length of a sector
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.set NUM_SECTORS,2 # Total length in sectors
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.set FAKE,ORIGIN+(SECTOR_SIZE*NUM_SECTORS) # Partition entry
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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,table0_end-table0 # Table 0 size
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.set TBL1SZ,table1_end-table1 # Table 1 size
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.set TBL0SZ,0x3 # Table 0 size
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.set TBL1SZ,0xb # 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 KEY_1,0x02 # #1 key scan code
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#
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# Flag bits
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#
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.set FL_PACKET,0x80 # Packet mode
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.set FL_NOUPDATE,0x40 # Don't save selection
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.set FL_SETDRV,0x20 # Override drive number
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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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#
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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 sectors (%bp).
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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 _PRT_END,(FAKE-(ORIGIN+SECTOR_SIZE*(NUM_SECTORS-1)))
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.set _NXTDRV,-(_PRT_END+0x48) # Next drive
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.set _OPT,-(_PRT_END+0x47) # Default option
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.set _SETDRV,-(_PRT_END+0x46) # Drive to force
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.set _FLAGS,-(_PRT_END+0x45) # Flags
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.set _TICKS,-(_PRT_END+0x44) # Timeout ticks
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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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@ -63,58 +61,63 @@
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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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# Note that this section of code is used as the first signature check in
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# boot0cfg(8).
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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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# End signature code
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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 $fake,%bp # Address variables
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movw %bp,%di # %di used in stosw
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movw $0x8,%cx # Words to clear
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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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incb -0xe(%di) # Sector number 1
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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 $FL_SETDRV,LOAD+flags-start # Set number drive?
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jnz boot.1 # Yes
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testb %dl,%dl # Drive number valid?
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js boot.2 # Possibly (0x80 set)
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boot.1: movb LOAD+setdrv-start,%dl # Drive number to use
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boot.2:
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#
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# Reload all of boot0 (including the extra sectors) into memory at the
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# relocation address.
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#
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push %dx # Save drive number
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movw $start,%bx # Origin we were linked for
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movw %bp,%si # Fake PTE
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movw $0x200+NUM_SECTORS,%ax # Read in all
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callw intx13 # of boot0
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pop %dx # Restore
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#
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# Relocate to the new copy of the code.
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#
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jmp main+ORIGIN-LOAD # To relocated code
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incb -0xe(%di) # Sector number
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jmp main-LOAD+ORIGIN # To relocated code
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main:
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#ifdef SIO
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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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pushw %dx # Save
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xorw %dx,%dx # Port: COM1
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movb COMSPEED,%al # defined by Makefile
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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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#endif /* SIO */
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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: movb %dl,_FAKE(%bp) # Save drive number
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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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@ -153,7 +156,7 @@ main.3: movb %ch,-0x4(%bx) # Zero active flag (ch == 0)
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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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# 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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@ -172,11 +175,13 @@ main.5: incw %dx # Next item
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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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#
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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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#
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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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@ -201,20 +206,39 @@ main.7: movw $prompt,%si # Display
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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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#ifndef SIO
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movw %dx,%di # Ticks when
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addw _TICKS(%bp),%di # timeout
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#else /* SIO */
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movw %dx,%si # Ticks when
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addw _TICKS(%bp),%si # timeout
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#endif /* SIO */
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#
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# Busy loop, looking for keystrokes but
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# keeping one eye on the time.
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#
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main.8: movb $0x1,%ah # BIOS: Check
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main.8:
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#ifndef SIO
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movb $0x1,%ah # BIOS: Check
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int $0x16 # for keypress
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jnz main.11 # Have one
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#else /* SIO */
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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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#endif /* SIO */
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xorb %ah,%ah # BIOS: Get
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int $0x1a # system time
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#ifndef SIO
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cmpw %di,%dx # Timeout?
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#else /* SIO */
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cmpw %si,%dx # Timeout?
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#endif /* SIO */
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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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@ -228,27 +252,44 @@ main.9: movb _OPT(%bp),%al # Load default
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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 $0x7,%al # Signal
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main.10: movb $ASCII_BEL,%al # Signal
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callw putchr # error
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#ifdef SIO
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jmp main.7_1 # Go back
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#endif /* SIO */
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#
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# Get the keystroke.
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#
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main.11: xorb %ah,%ah # BIOS: Get
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main.11:
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#ifndef SIO
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xorb %ah,%ah # BIOS: Get
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int $0x16 # keypress
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movb %ah,%al # Scan code
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#else /* SIO */
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movb $0x02,%ah # BIOS: Receive
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int $0x14 # COM Byte
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#endif /* SIO */
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#
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# If it's CR act as if timed out.
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#
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#ifndef SIO
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cmpb $KEY_ENTER,%al # Enter pressed?
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#else /* SIO */
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cmpb $ASCII_CR,%al # Enter pressed?
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#endif /* SIO */
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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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#ifndef SIO
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subb $KEY_F1,%al # Less F1 scan code
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cmpb $0x4,%al # F1..F5?
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jna main.12 # Yes
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subb $(KEY_1 - KEY_F1),%al # Less #1 scan code
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#else /* SIO */
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subb $'1',%al # Less '1' ascii character
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#endif /* SIO */
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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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@ -265,7 +306,7 @@ main.12: cbtw # Option
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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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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 # F5/#5 pressed?
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@ -279,10 +320,10 @@ main.12: cbtw # Option
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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 $FL_NOUPDATE,_FLAGS(%bp) # Skip update?
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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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movw $0x301,%ax # Write 1 sector
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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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@ -297,22 +338,28 @@ main.14: popw %si # Restore
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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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movw $0x201,%ax # Read 1 sector
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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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callw putn # Leave some space
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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 $'F',%al # Display
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putkey:
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#ifndef SIO
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movb $'F',%al # Display
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callw putchr # 'F'
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#endif /* SIO */
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movb $'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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@ -337,82 +384,104 @@ 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 %bx # Save
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putchr:
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#ifndef SIO
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pushw %bx # Save
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movw $0x7,%bx # Page:attribute
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movb $0xe,%ah # BIOS: Display
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int $0x10 # character
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popw %bx # Restore
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#else /* SIO */
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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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#endif /* SIO */
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retw # To caller
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|
||||
# One-sector disk I/O routine
|
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#
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# Calling conventions: (assumes %si -> partition table entry)
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#
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# 0x1(%si) - byte - head
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# 0x2(%si) - word - cylinder/sector
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# 0x8(%si) - long - LBA to use if needed
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# %ah - byte - operation, 2 = read, 3 = write
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# %al - byte - sector count
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# %dl - byte - drive number
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# %es:(%bx) - void - buffer to use for transfer
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||||
#
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||||
# If the head == 0xff, and cylinder/sector == 0xffff, then try
|
||||
# to use the EDD stuff with the LBA offset instead of CHS. However,
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# use CHS if at all possible.
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||||
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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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cmpb $0xff,%dh # Might we need LBA?
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jne intx13.2 # No, just use CHS
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cmpw $0xffff,%cx # Do we need LBA?
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jne intx13.2 # No
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||||
testb $FL_PACKET,_FLAGS(%bp) # Try the packet interface?
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jz intx13.2 # No
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||||
pushw %cx # Save
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||||
pushw %bx # Save
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||||
movw $0x55aa,%bx # Magic
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||||
pushw %ax # Save
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||||
movb $0x41,%ah # BIOS: EDD extensions
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||||
int $0x13 # present?
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popw %ax # Restore
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||||
jc intx13.1 # Not present, use CHS
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cmpw $0xaa55,%bx # Magic?
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jne intx13.1 # Not present, use CHS
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testb $0x1,%cl # Packet mode available?
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jz intx13.1 # No, use CHS
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orb $0x40,%ah # Use disk packet
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intx13.1: popw %bx # Restore
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popw %cx # Restore
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||||
testb $0x40,%ah # Using packet mode?
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jz intx13.2 # No, so skip the rest
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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 $0x0 # Punch a hole in the stack
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||||
push $0x10 # Packet size
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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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||||
xchgb %al,0x2(%si) # Set the block count in the
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||||
# packet and zero %al,
|
||||
# turning verify off for writes
|
||||
intx13.2: int $0x13 # BIOS: Disk I/O
|
||||
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
|
||||
|
||||
#ifndef SIO
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDefault:"; .byte ' '|0x80
|
||||
#else /* SIO */
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDef:"; .byte ' '|0x80
|
||||
#endif /* SIO */
|
||||
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, 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_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_linux: .ascii "Linu"; .byte 'x'|0x80
|
||||
os_freebsd: .ascii "Free"
|
||||
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.
|
||||
#
|
||||
# Note that the 'drive' string variable is used as the second signature
|
||||
# check in boot0cfg(8).
|
||||
#
|
||||
version_minor: .byte 0x1 # minor version
|
||||
version_major: .byte 0x1 # major version
|
||||
drive: .ascii "Drive "
|
||||
nxtdrv: .byte 0x0 # Next drive number
|
||||
opt: .byte 0x0 # Option
|
||||
@ -425,69 +494,3 @@ ticks: .word TICKS # Delay
|
||||
#
|
||||
partbl: .fill 0x40,0x1,0x0 # Partition table
|
||||
.word MAGIC # Magic number
|
||||
|
||||
#
|
||||
# start of sector two.. ugh
|
||||
#
|
||||
.org SECTOR_SIZE,0x90
|
||||
# Menu strings
|
||||
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDefault:"; .byte ' '|0x80
|
||||
crlf: .ascii "\r"; .byte '\n'|0x80
|
||||
|
||||
# Partition type tables
|
||||
|
||||
tables:
|
||||
#
|
||||
# These entries identify invalid or NON BOOT types and partitions.
|
||||
#
|
||||
table0: .byte 0x0, 0x5, 0xf
|
||||
table0_end:
|
||||
#
|
||||
# These values indicate bootable types we know the names of
|
||||
#
|
||||
table1: .byte 0x1, 0x4, 0x6, 0x7, 0xb, 0xc, 0xe, 0x42, 0x63, 0x83
|
||||
.byte 0x9f, 0xa5, 0xa6, 0xa9
|
||||
table1_end:
|
||||
#
|
||||
# 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_nt-. # NT/XP or OS/2
|
||||
.byte os_windows-. # Windows 32-bit FAT
|
||||
.byte os_windows-. # Windows 32-bit FAT ext int 13
|
||||
.byte os_windows-. # Windows
|
||||
.byte os_windows-. # Windows 2000 dyn ext
|
||||
.byte os_unix-. # UNIX
|
||||
.byte os_linux-. # Linux
|
||||
.byte os_bsdos-. # BSD/OS
|
||||
.byte os_freebsd-. # FreeBSD
|
||||
.byte os_openbsd-. # OpenBSD
|
||||
.byte os_netbsd-. # 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 "Unknow"; .byte 'n'|0x80
|
||||
os_dos: .ascii "DO"; .byte 'S'|0x80
|
||||
os_nt: .ascii "Windows NT/X"; .byte 'P'|0x80
|
||||
os_windows: .ascii "Window"; .byte 's'|0x80
|
||||
os_unix: .ascii "UNI"; .byte 'X'|0x80
|
||||
os_linux: .ascii "Linu"; .byte 'x'|0x80
|
||||
os_freebsd: .ascii "FreeBS"; .byte 'D'|0x80
|
||||
os_openbsd: .ascii "OpenBS"; .byte 'D'|0x80
|
||||
os_netbsd: .ascii "NetBS"; .byte 'D'|0x80
|
||||
os_bsdos: .ascii "BSD/O"; .byte 'S'|0x80
|
||||
|
||||
#
|
||||
# Fake partition entry created at the end of the table used when loading
|
||||
# boot0 at the very beginning and when loading an MBR from another disk when
|
||||
# F5 is pressed.
|
||||
#
|
||||
.org SECTOR_SIZE*NUM_SECTORS, 0x0
|
||||
fake:
|
||||
@ -1,494 +0,0 @@
|
||||
//
|
||||
// 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.
|
||||
#ifdef SIO
|
||||
// ... using serial port COM1
|
||||
#endif /* SIO */
|
||||
|
||||
.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,0xb // 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 KEY_1,0x02 // #1 key scan code
|
||||
|
||||
.set ASCII_BEL,0x07 // ASCII code for <BEL>
|
||||
.set ASCII_CR,0x0D // ASCII code for <CR>
|
||||
|
||||
//
|
||||
// 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
|
||||
main:
|
||||
|
||||
#ifdef SIO
|
||||
|
||||
//
|
||||
// Initialize the serial port.
|
||||
// Must save DX (contains drive number)
|
||||
//
|
||||
pushw %dx // Save
|
||||
xorw %dx,%dx // Port: COM1
|
||||
movb COMSPEED,%al // defined by Makefile
|
||||
movb $0x00,%ah // BIOS: Set COM Port
|
||||
int $0x14 // Parameters
|
||||
popw %dx // Restore
|
||||
#endif /* SIO */
|
||||
//
|
||||
// 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.
|
||||
// Get ready for the input by noting the time.
|
||||
//
|
||||
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
|
||||
#ifndef SIO
|
||||
movw %dx,%di // Ticks when
|
||||
addw _TICKS(%bp),%di // timeout
|
||||
#else /* SIO */
|
||||
movw %dx,%si // Ticks when
|
||||
addw _TICKS(%bp),%si // timeout
|
||||
#endif /* SIO */
|
||||
//
|
||||
// Busy loop, looking for keystrokes but
|
||||
// keeping one eye on the time.
|
||||
//
|
||||
main.8:
|
||||
#ifndef SIO
|
||||
movb $0x1,%ah // BIOS: Check
|
||||
int $0x16 // for keypress
|
||||
jnz main.11 // Have one
|
||||
#else /* SIO */
|
||||
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)
|
||||
#endif /* SIO */
|
||||
xorb %ah,%ah // BIOS: Get
|
||||
int $0x1a // system time
|
||||
#ifndef SIO
|
||||
cmpw %di,%dx // Timeout?
|
||||
#else /* SIO */
|
||||
cmpw %si,%dx // Timeout?
|
||||
#endif /* SIO */
|
||||
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
|
||||
#ifdef SIO
|
||||
jmp main.7_1 // Go back
|
||||
#endif /* SIO */
|
||||
//
|
||||
// Get the keystroke.
|
||||
//
|
||||
main.11:
|
||||
#ifndef SIO
|
||||
xorb %ah,%ah // BIOS: Get
|
||||
int $0x16 // keypress
|
||||
movb %ah,%al // Scan code
|
||||
#else /* SIO */
|
||||
movb $0x02,%ah // BIOS: Receive
|
||||
int $0x14 // COM Byte
|
||||
#endif /* SIO */
|
||||
//
|
||||
// If it's CR act as if timed out.
|
||||
//
|
||||
#ifndef SIO
|
||||
cmpb $KEY_ENTER,%al // Enter pressed?
|
||||
#else /* SIO */
|
||||
cmpb $ASCII_CR,%al // Enter pressed?
|
||||
#endif /* SIO */
|
||||
je main.9 // Yes
|
||||
//
|
||||
// Otherwise check if legal
|
||||
// If not ask again.
|
||||
//
|
||||
#ifndef SIO
|
||||
subb $KEY_F1,%al // Less F1 scan code
|
||||
cmpb $0x4,%al // F1..F5?
|
||||
jna main.12 // Yes
|
||||
subb $(KEY_1 - KEY_F1),%al // Less #1 scan code
|
||||
#else /* SIO */
|
||||
subb $'1',%al // Less '1' ascii character
|
||||
#endif /* SIO */
|
||||
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 // F5/#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 F5/#5
|
||||
movb _NXTDRV(%bp),%dl // Next drive
|
||||
subb $'0',%dl // number
|
||||
//
|
||||
// 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:
|
||||
#ifndef SIO
|
||||
movb $'F',%al // Display
|
||||
callw putchr // 'F'
|
||||
#endif /* SIO */
|
||||
movb $'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
|
||||
|
||||
#ifndef SIO
|
||||
putchr: pushw %bx // Save
|
||||
movw $0x7,%bx // Page:attribute
|
||||
movb $0xe,%ah // BIOS: Display
|
||||
int $0x10 // character
|
||||
popw %bx // Restore
|
||||
#else /* SIO */
|
||||
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
|
||||
#endif /* SIO */
|
||||
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
|
||||
|
||||
#ifndef SIO
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDefault:"; .byte ' '|0x80
|
||||
#else /* SIO */
|
||||
item: .ascii " "; .byte ' '|0x80
|
||||
prompt: .ascii "\nDef:"; .byte ' '|0x80
|
||||
#endif /* SIO */
|
||||
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, 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_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_linux: .ascii "Linu"; .byte 'x'|0x80
|
||||
os_freebsd: .ascii "Free"
|
||||
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