diff options
author | ru <ru@FreeBSD.org> | 2004-04-28 20:55:01 +0000 |
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committer | ru <ru@FreeBSD.org> | 2004-04-28 20:55:01 +0000 |
commit | 34a1e6ae2521c61f9f751bd4c5e6e71131fa6f7c (patch) | |
tree | 286773cb8e540bd18b404a1756ad7ef1f3c33534 /sys/boot | |
parent | e8beb8e0d4d15cc8ec322f2e9e52e00a1a931a73 (diff) | |
download | FreeBSD-src-34a1e6ae2521c61f9f751bd4c5e6e71131fa6f7c.zip FreeBSD-src-34a1e6ae2521c61f9f751bd4c5e6e71131fa6f7c.tar.gz |
Switch to using C99 comments in assembler preprocessed with cpp(1).
Diffstat (limited to 'sys/boot')
-rw-r--r-- | sys/boot/i386/boot0/boot0.S | 828 |
1 files changed, 414 insertions, 414 deletions
diff --git a/sys/boot/i386/boot0/boot0.S b/sys/boot/i386/boot0/boot0.S index c1c97c4..9b790de 100644 --- a/sys/boot/i386/boot0/boot0.S +++ b/sys/boot/i386/boot0/boot0.S @@ -1,430 +1,430 @@ -# -# 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. -# -# $FreeBSD$ -# +/* + * 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. +/* A 512-byte boot manager. */ #ifdef SIO -# ... using a serial console on COM1. +/* ... using a serial console on 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 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 PRT_OFF,0x1be // Partition table - .set TBL0SZ,0x3 # Table 0 size - .set TBL1SZ,0xb # Table 1 size + .set TBL0SZ,0x3 // Table 0 size + .set TBL1SZ,0xb // Table 1 size - .set MAGIC,0xaa55 # Magic: bootable - .set B0MAGIC,0xbb66 # Identification + .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 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> + .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 +/* + * 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 + .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 +/* + * 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 +/* + * 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 +/* + * 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 +/* + * 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 + xorb %ah,%ah // BIOS: Get + int $0x1a // system time #ifndef SIO - movw %dx,%di # Ticks when - addw _TICKS(%bp),%di # timeout + movw %dx,%di // Ticks when + addw _TICKS(%bp),%di // timeout #else /* SIO */ - movw %dx,%si # Ticks when - addw _TICKS(%bp),%si # timeout + movw %dx,%si // Ticks when + addw _TICKS(%bp),%si // timeout #endif /* SIO */ -# -# Busy loop, looking for keystrokes but -# keeping one eye on the time. -# +/* + * 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 + 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) + 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 + xorb %ah,%ah // BIOS: Get + int $0x1a // system time #ifndef SIO - cmpw %di,%dx # Timeout? + cmpw %di,%dx // Timeout? #else /* SIO */ - cmpw %si,%dx # Timeout? + 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 + 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 + jmp main.7_1 // Go back #endif /* SIO */ -# -# Get the keystroke. -# +/* + * Get the keystroke. + */ main.11: #ifndef SIO - xorb %ah,%ah # BIOS: Get - int $0x16 # keypress - movb %ah,%al # Scan code + xorb %ah,%ah // BIOS: Get + int $0x16 // keypress + movb %ah,%al // Scan code #else /* SIO */ - movb $0x02,%ah # BIOS: Receive - int $0x14 # COM Byte + movb $0x02,%ah // BIOS: Receive + int $0x14 // COM Byte #endif /* SIO */ -# -# If it's CR act as if timed out. -# +/* + * If it's CR act as if timed out. + */ #ifndef SIO - cmpb $KEY_ENTER,%al # Enter pressed? + cmpb $KEY_ENTER,%al // Enter pressed? #else /* SIO */ - cmpb $ASCII_CR,%al # Enter pressed? + cmpb $ASCII_CR,%al // Enter pressed? #endif /* SIO */ - je main.9 # Yes -# -# Otherwise check if legal -# If not ask again. -# + 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 + 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 + 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 + 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 -# +/* + * Display routines + */ putkey: #ifndef SIO - movb $'F',%al # Display - callw putchr # 'F' + movb $'F',%al // Display + callw putchr // 'F' #endif /* SIO */ - movb $'1',%al # Prepare - addb %dl,%al # digit - jmp putstr.1 # Display the rest + 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 +/* + * 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 +puts: callw putstr // Display string -putn: movw $crlf,%si # To next line +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 +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: #ifndef SIO - pushw %bx # Save - movw $0x7,%bx # Page:attribute - movb $0xe,%ah # BIOS: Display - int $0x10 # character - popw %bx # Restore + pushw %bx // Save + movw $0x7,%bx // Page:attribute + movb $0xe,%ah // BIOS: Display + int $0x10 // character + popw %bx // Restore #else /* SIO */ - pushw %dx # Save - xorw %dx,%dx # Use COM1 - xorw %cx,%cx # No timeout - movb $0x01,%ah # BIOS: Send - int $0x14 # Character - popw %dx # Restore + 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 + retw // To caller -# One-sector disk I/O routine +/* 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 +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 +/* Menu strings */ #ifndef SIO item: .ascii " "; .byte ' '|0x80 @@ -435,38 +435,38 @@ prompt: .ascii "\nDef:"; .byte ' '|0x80 #endif /* SIO */ crlf: .ascii "\r"; .byte '\n'|0x80 -# Partition type tables +/* Partition type tables */ tables: -# -# These entries identify invalid or NON BOOT types and partitions. -# +/* + * These entries identify invalid or NON BOOT types and partitions. + */ .byte 0x0, 0x5, 0xf -# -# These values indicate bootable types we know the names of -# +/* + * 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...) -# +/* + * 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 @@ -475,22 +475,22 @@ os_bsd: .ascii "BS"; .byte 'D'|0x80 .org PRT_OFF-0xe,0x90 - .word B0MAGIC # Magic number + .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. -# +/* + * 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 +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 +/* + * here is the 64 byte partition table that fdisk would fiddle with. + */ +partbl: .fill 0x40,0x1,0x0 // Partition table + .word MAGIC // Magic number |