Back out last revision that unnecessarily changed valid assembler

line comments and damaged the CVS history.

Prompted by:	bde, jhb

1 files changed, 920 insertions, 921 deletions

diff --git a/sys/boot/i386/btx/btx/btx.S b/sys/boot/i386/btx/btx/btx.S
index 77cfe861a377..7581519ba536 100644
--- a/sys/boot/i386/btx/btx/btx.S
+++ b/sys/boot/i386/btx/btx/btx.S
@@ -18,588 +18,587 @@
 /*
  * Memory layout.
  */
-		.set MEM_BTX,0x1000		// Start of BTX memory
-		.set MEM_ESP0,0x1800		// Supervisor stack
-		.set MEM_BUF,0x1800		// Scratch buffer
-		.set MEM_ESP1,0x1e00		// Link stack
-		.set MEM_IDT,0x1e00		// IDT
-		.set MEM_TSS,0x1f98		// TSS
-		.set MEM_MAP,0x2000		// I/O bit map
-		.set MEM_DIR,0x4000		// Page directory
-		.set MEM_TBL,0x5000		// Page tables
-		.set MEM_ORG,0x9000		// BTX code
-		.set MEM_USR,0xa000		// Start of user memory
+		.set MEM_BTX,0x1000		# Start of BTX memory
+		.set MEM_ESP0,0x1800		# Supervisor stack
+		.set MEM_BUF,0x1800		# Scratch buffer
+		.set MEM_ESP1,0x1e00		# Link stack
+		.set MEM_IDT,0x1e00		# IDT
+		.set MEM_TSS,0x1f98		# TSS
+		.set MEM_MAP,0x2000		# I/O bit map
+		.set MEM_DIR,0x4000		# Page directory
+		.set MEM_TBL,0x5000		# Page tables
+		.set MEM_ORG,0x9000		# BTX code
+		.set MEM_USR,0xa000		# Start of user memory
 /*
  * Paging control.
  */
-		.set PAG_SIZ,0x1000		// Page size
-		.set PAG_CNT,0x1000		// Pages to map
+		.set PAG_SIZ,0x1000		# Page size
+		.set PAG_CNT,0x1000		# Pages to map
 /*
  * Segment selectors.
  */
-		.set SEL_SCODE,0x8		// Supervisor code
-		.set SEL_SDATA,0x10		// Supervisor data
-		.set SEL_RCODE,0x18		// Real mode code
-		.set SEL_RDATA,0x20		// Real mode data
-		.set SEL_UCODE,0x28|3		// User code
-		.set SEL_UDATA,0x30|3		// User data
-		.set SEL_TSS,0x38		// TSS
+		.set SEL_SCODE,0x8		# Supervisor code
+		.set SEL_SDATA,0x10		# Supervisor data
+		.set SEL_RCODE,0x18		# Real mode code
+		.set SEL_RDATA,0x20		# Real mode data
+		.set SEL_UCODE,0x28|3		# User code
+		.set SEL_UDATA,0x30|3		# User data
+		.set SEL_TSS,0x38		# TSS
 /*
  * Task state segment fields.
  */
-		.set TSS_ESP0,0x4		// PL 0 ESP
-		.set TSS_SS0,0x8		// PL 0 SS
-		.set TSS_ESP1,0xc		// PL 1 ESP
-		.set TSS_MAP,0x66		// I/O bit map base
+		.set TSS_ESP0,0x4		# PL 0 ESP
+		.set TSS_SS0,0x8		# PL 0 SS
+		.set TSS_ESP1,0xc		# PL 1 ESP
+		.set TSS_MAP,0x66		# I/O bit map base
 /*
  * System calls.
  */
-		.set SYS_EXIT,0x0		// Exit
-		.set SYS_EXEC,0x1		// Exec
+		.set SYS_EXIT,0x0		# Exit
+		.set SYS_EXEC,0x1		# Exec
 /*
  * V86 constants.
  */
-		.set V86_FLG,0x208eff		// V86 flag mask
-		.set V86_STK,0x400		// V86 stack allowance
+		.set V86_FLG,0x208eff		# V86 flag mask
+		.set V86_STK,0x400		# V86 stack allowance
 /*
  * Dump format control bytes.
  */
-		.set DMP_X16,0x1		// Word
-		.set DMP_X32,0x2		// Long
-		.set DMP_MEM,0x4		// Memory
-		.set DMP_EOL,0x8		// End of line
+		.set DMP_X16,0x1		# Word
+		.set DMP_X32,0x2		# Long
+		.set DMP_MEM,0x4		# Memory
+		.set DMP_EOL,0x8		# End of line
 /*
  * Screen defaults and assumptions.
  */
-		.set SCR_MAT,0x7		// Mode/attribute
-		.set SCR_COL,0x50		// Columns per row
-		.set SCR_ROW,0x19		// Rows per screen
+		.set SCR_MAT,0x7		# Mode/attribute
+		.set SCR_COL,0x50		# Columns per row
+		.set SCR_ROW,0x19		# Rows per screen
 /*
  * BIOS Data Area locations.
  */
-		.set BDA_MEM,0x413		// Free memory
-		.set BDA_KEYFLAGS,0x417		// Keyboard shift-state flags
-		.set BDA_SCR,0x449		// Video mode
-		.set BDA_POS,0x450		// Cursor position
-		.set BDA_BOOT,0x472		// Boot howto flag
+		.set BDA_MEM,0x413		# Free memory
+		.set BDA_KEYFLAGS,0x417		# Keyboard shift-state flags
+		.set BDA_SCR,0x449		# Video mode
+		.set BDA_POS,0x450		# Cursor position
+		.set BDA_BOOT,0x472		# Boot howto flag
 /*
  * Derivations, for brevity.
  */
-		.set _ESP0H,MEM_ESP0>>0x8	// Byte 1 of ESP0
-		.set _ESP1H,MEM_ESP1>>0x8	// Byte 1 of ESP1
-		.set _TSSIO,MEM_MAP-MEM_TSS	// TSS I/O base
-		.set _TSSLM,MEM_DIR-MEM_TSS-1	// TSS limit
-		.set _IDTLM,MEM_TSS-MEM_IDT-1	// IDT limit
+		.set _ESP0H,MEM_ESP0>>0x8	# Byte 1 of ESP0
+		.set _ESP1H,MEM_ESP1>>0x8	# Byte 1 of ESP1
+		.set _TSSIO,MEM_MAP-MEM_TSS	# TSS I/O base
+		.set _TSSLM,MEM_DIR-MEM_TSS-1	# TSS limit
+		.set _IDTLM,MEM_TSS-MEM_IDT-1	# IDT limit
 /*
  * Code segment.
  */
 		.globl start
 		.code16
-start:						// Start of code
+start:						# Start of code
 /*
  * BTX header.
  */
-btx_hdr:	.byte 0xeb			// Machine ID
-		.byte 0xe			// Header size
-		.ascii "BTX"			// Magic
-		.byte 0x1			// Major version
-		.byte 0x1			// Minor version
-		.byte BTX_FLAGS			// Flags
-		.word PAG_CNT-MEM_ORG>>0xc	// Paging control
-		.word break-start		// Text size
-		.long 0x0			// Entry address
+btx_hdr:	.byte 0xeb			# Machine ID
+		.byte 0xe			# Header size
+		.ascii "BTX"			# Magic
+		.byte 0x1			# Major version
+		.byte 0x1			# Minor version
+		.byte BTX_FLAGS			# Flags
+		.word PAG_CNT-MEM_ORG>>0xc	# Paging control
+		.word break-start		# Text size
+		.long 0x0			# Entry address
 /*
  * Initialization routine.
  */
-init:		cli				// Disable interrupts
-		xor %ax,%ax			// Zero/segment
-		mov %ax,%ss			// Set up
-		mov $MEM_ESP0,%sp		//  stack
-		mov %ax,%es			// Address
-		mov %ax,%ds			//  data
-		pushl $0x2			// Clear
-		popfl				//  flags
+init:		cli				# Disable interrupts
+		xor %ax,%ax			# Zero/segment
+		mov %ax,%ss			# Set up
+		mov $MEM_ESP0,%sp		#  stack
+		mov %ax,%es			# Address
+		mov %ax,%ds			#  data
+		pushl $0x2			# Clear
+		popfl				#  flags
 /*
  * Initialize memory.
  */
-		mov $MEM_IDT,%di		// Memory to initialize
-		mov $(MEM_ORG-MEM_IDT)/2,%cx	// Words to zero
-		push %di			// Save
-		rep				// Zero-fill
-		stosw				//  memory
-		pop %di				// Restore
+		mov $MEM_IDT,%di		# Memory to initialize
+		mov $(MEM_ORG-MEM_IDT)/2,%cx	# Words to zero
+		push %di			# Save
+		rep				# Zero-fill
+		stosw				#  memory
+		pop %di				# Restore
 /*
  * Create IDT.
  */
-		mov $idtctl,%si			// Control string
-init.1: 	lodsb				// Get entry
-		cbw				//  count
-		xchg %ax,%cx			//  as word
-		jcxz init.4			// If done
-		lodsb				// Get segment
-		xchg %ax,%dx	 		//  P:DPL:type
-		lodsw				// Get control
-		xchg %ax,%bx			//  set
-		lodsw				// Get handler offset
-		mov $SEL_SCODE,%dh		// Segment selector
-init.2: 	shr %bx				// Handle this int?
-		jnc init.3			// No
-		mov %ax,(%di)			// Set handler offset
-		mov %dh,0x2(%di)		//  and selector
-		mov %dl,0x5(%di)		// Set P:DPL:type
-		add $0x4,%ax			// Next handler
-init.3: 	lea 0x8(%di),%di		// Next entry
-		loop init.2			// Till set done
-		jmp init.1			// Continue
+		mov $idtctl,%si			# Control string
+init.1: 	lodsb				# Get entry
+		cbw				#  count
+		xchg %ax,%cx			#  as word
+		jcxz init.4			# If done
+		lodsb				# Get segment
+		xchg %ax,%dx	 		#  P:DPL:type
+		lodsw				# Get control
+		xchg %ax,%bx			#  set
+		lodsw				# Get handler offset
+		mov $SEL_SCODE,%dh		# Segment selector
+init.2: 	shr %bx				# Handle this int?
+		jnc init.3			# No
+		mov %ax,(%di)			# Set handler offset
+		mov %dh,0x2(%di)		#  and selector
+		mov %dl,0x5(%di)		# Set P:DPL:type
+		add $0x4,%ax			# Next handler
+init.3: 	lea 0x8(%di),%di		# Next entry
+		loop init.2			# Till set done
+		jmp init.1			# Continue
 /*
  * Initialize TSS.
  */
-init.4: 	movb $_ESP0H,TSS_ESP0+1(%di)	// Set ESP0
-		movb $SEL_SDATA,TSS_SS0(%di)	// Set SS0
-		movb $_ESP1H,TSS_ESP1+1(%di)	// Set ESP1
-		movb $_TSSIO,TSS_MAP(%di)	// Set I/O bit map base
+init.4: 	movb $_ESP0H,TSS_ESP0+1(%di)	# Set ESP0
+		movb $SEL_SDATA,TSS_SS0(%di)	# Set SS0
+		movb $_ESP1H,TSS_ESP1+1(%di)	# Set ESP1
+		movb $_TSSIO,TSS_MAP(%di)	# Set I/O bit map base
 #ifdef PAGING
 /*
  * Create page directory.
  */
-		xor %edx,%edx			// Page
-		mov $PAG_SIZ>>0x8,%dh		//  size
-		xor %eax,%eax			// Zero
-		mov $MEM_DIR,%di		// Page directory
-		mov $PAG_CNT>>0xa,%cl		// Entries
-		mov $MEM_TBL|0x7,%ax	 	// First entry
-init.5: 	stosl				// Write entry
-		add %dx,%ax			// To next
-		loop init.5			// Till done
+		xor %edx,%edx			# Page
+		mov $PAG_SIZ>>0x8,%dh		#  size
+		xor %eax,%eax			# Zero
+		mov $MEM_DIR,%di		# Page directory
+		mov $PAG_CNT>>0xa,%cl		# Entries
+		mov $MEM_TBL|0x7,%ax	 	# First entry
+init.5: 	stosl				# Write entry
+		add %dx,%ax			# To next
+		loop init.5			# Till done
 /*
  * Create page tables.
  */
-		mov $MEM_TBL,%di		// Page table
-		mov $PAG_CNT>>0x8,%ch		// Entries
-		xor %ax,%ax			// Start address
-init.6: 	mov $0x7,%al			// Set U:W:P flags
-		cmp btx_hdr+0x8,%cx	 	// Standard user page?
-		jb init.7			// Yes
-		cmp $PAG_CNT-MEM_BTX>>0xc,%cx	// BTX memory?
-		jae init.7			// No or first page
-		and $~0x2,%al			// Clear W flag
-		cmp $PAG_CNT-MEM_USR>>0xc,%cx	// User page zero?
-		jne init.7			// No
-		testb $0x80,btx_hdr+0x7		// Unmap it?
-		jz init.7			// No
-		and $~0x1,%al			// Clear P flag
-init.7: 	stosl				// Set entry
-		add %edx,%eax			// Next address
-		loop init.6			// Till done
+		mov $MEM_TBL,%di		# Page table
+		mov $PAG_CNT>>0x8,%ch		# Entries
+		xor %ax,%ax			# Start address
+init.6: 	mov $0x7,%al			# Set U:W:P flags
+		cmp btx_hdr+0x8,%cx	 	# Standard user page?
+		jb init.7			# Yes
+		cmp $PAG_CNT-MEM_BTX>>0xc,%cx	# BTX memory?
+		jae init.7			# No or first page
+		and $~0x2,%al			# Clear W flag
+		cmp $PAG_CNT-MEM_USR>>0xc,%cx	# User page zero?
+		jne init.7			# No
+		testb $0x80,btx_hdr+0x7		# Unmap it?
+		jz init.7			# No
+		and $~0x1,%al			# Clear P flag
+init.7: 	stosl				# Set entry
+		add %edx,%eax			# Next address
+		loop init.6			# Till done
 #endif
 /*
  * Bring up the system.
  */
-		mov $0x2820,%bx			// Set protected mode
-		callw setpic			//  IRQ offsets
-		lidt idtdesc	 		// Set IDT
+		mov $0x2820,%bx			# Set protected mode
+		callw setpic			#  IRQ offsets
+		lidt idtdesc	 		# Set IDT
 #ifdef PAGING
-		xor %eax,%eax			// Set base
-		mov $MEM_DIR>>0x8,%ah		//  of page
-		mov %eax,%cr3			//  directory
+		xor %eax,%eax			# Set base
+		mov $MEM_DIR>>0x8,%ah		#  of page
+		mov %eax,%cr3			#  directory
 #endif
-		lgdt gdtdesc	 		// Set GDT
-		mov %cr0,%eax			// Switch to protected
+		lgdt gdtdesc	 		# Set GDT
+		mov %cr0,%eax			# Switch to protected
 #ifdef PAGING
-		or $0x80000001,%eax             //  mode and enable paging
+		or $0x80000001,%eax             #  mode and enable paging
 #else
-		or $0x01,%eax			//  mode
+		or $0x01,%eax			#  mode
 #endif
-		mov %eax,%cr0			//
-		ljmp $SEL_SCODE,$init.8		// To 32-bit code
+		mov %eax,%cr0			#
+		ljmp $SEL_SCODE,$init.8		# To 32-bit code
 		.code32
-init.8: 	xorl %ecx,%ecx			// Zero
-		movb $SEL_SDATA,%cl		// To 32-bit
-		movw %cx,%ss			//  stack
+init.8: 	xorl %ecx,%ecx			# Zero
+		movb $SEL_SDATA,%cl		# To 32-bit
+		movw %cx,%ss			#  stack
 /*
  * Launch user task.
  */
-		movb $SEL_TSS,%cl		// Set task
-		ltr %cx				//  register
-		movl $MEM_USR,%edx		// User base address
-		movzwl %ss:BDA_MEM,%eax 	// Get free memory
-		shll $0xa,%eax			// To bytes
-		subl $0x1000,%eax		// Less arg space
-		subl %edx,%eax			// Less base
-		movb $SEL_UDATA,%cl		// User data selector
-		pushl %ecx			// Set SS
-		pushl %eax			// Set ESP
-		push $0x202			// Set flags (IF set)
-		push $SEL_UCODE			// Set CS
-		pushl btx_hdr+0xc		// Set EIP
-		pushl %ecx			// Set GS
-		pushl %ecx			// Set FS
-		pushl %ecx			// Set DS
-		pushl %ecx			// Set ES
-		pushl %edx			// Set EAX
-		movb $0x7,%cl			// Set remaining
-init.9:		push $0x0			//  general
-		loop init.9			//  registers
+		movb $SEL_TSS,%cl		# Set task
+		ltr %cx				#  register
+		movl $MEM_USR,%edx		# User base address
+		movzwl %ss:BDA_MEM,%eax 	# Get free memory
+		shll $0xa,%eax			# To bytes
+		subl $0x1000,%eax		# Less arg space
+		subl %edx,%eax			# Less base
+		movb $SEL_UDATA,%cl		# User data selector
+		pushl %ecx			# Set SS
+		pushl %eax			# Set ESP
+		push $0x202			# Set flags (IF set)
+		push $SEL_UCODE			# Set CS
+		pushl btx_hdr+0xc		# Set EIP
+		pushl %ecx			# Set GS
+		pushl %ecx			# Set FS
+		pushl %ecx			# Set DS
+		pushl %ecx			# Set ES
+		pushl %edx			# Set EAX
+		movb $0x7,%cl			# Set remaining
+init.9:		push $0x0			#  general
+		loop init.9			#  registers
 #ifdef BTX_SERIAL
-		call sio_init			// setup the serial console
+		call sio_init			# setup the serial console
 #endif
-		popa				//  and initialize
-		popl %es			// Initialize
-		popl %ds			//  user
-		popl %fs			//  segment
-		popl %gs			//  registers
-		iret				// To user mode
+		popa				#  and initialize
+		popl %es			# Initialize
+		popl %ds			#  user
+		popl %fs			#  segment
+		popl %gs			#  registers
+		iret				# To user mode
 /*
  * Exit routine.
  */
-exit:		cli				// Disable interrupts
-		movl $MEM_ESP0,%esp		// Clear stack
+exit:		cli				# Disable interrupts
+		movl $MEM_ESP0,%esp		# Clear stack
 /*
  * Turn off paging.
  */
-		movl %cr0,%eax			// Get CR0
-		andl $~0x80000000,%eax		// Disable
-		movl %eax,%cr0			//  paging
-		xorl %ecx,%ecx			// Zero
-		movl %ecx,%cr3			// Flush TLB
+		movl %cr0,%eax			# Get CR0
+		andl $~0x80000000,%eax		# Disable
+		movl %eax,%cr0			#  paging
+		xorl %ecx,%ecx			# Zero
+		movl %ecx,%cr3			# Flush TLB
 /*
  * Restore the GDT in case we caught a kernel trap.
  */
-		lgdt gdtdesc	 		// Set GDT
+		lgdt gdtdesc	 		# Set GDT
 /*
  * To 16 bits.
  */
-		ljmpw $SEL_RCODE,$exit.1	// Reload CS
+		ljmpw $SEL_RCODE,$exit.1	# Reload CS
 		.code16
-exit.1: 	mov $SEL_RDATA,%cl		// 16-bit selector
-		mov %cx,%ss			// Reload SS
-		mov %cx,%ds			// Load
-		mov %cx,%es			//  remaining
-		mov %cx,%fs			//  segment
-		mov %cx,%gs			//  registers
+exit.1: 	mov $SEL_RDATA,%cl		# 16-bit selector
+		mov %cx,%ss			# Reload SS
+		mov %cx,%ds			# Load
+		mov %cx,%es			#  remaining
+		mov %cx,%fs			#  segment
+		mov %cx,%gs			#  registers
 /*
  * To real-address mode.
  */
-		dec %ax				// Switch to
-		mov %eax,%cr0			//  real mode
-		ljmp $0x0,$exit.2		// Reload CS
-exit.2: 	xor %ax,%ax			// Real mode segment
-		mov %ax,%ss			// Reload SS
-		mov %ax,%ds			// Address data
-		mov $0x7008,%bx			// Set real mode
-		callw setpic			//  IRQ offsets
-		lidt ivtdesc	 		// Set IVT
+		dec %ax				# Switch to
+		mov %eax,%cr0			#  real mode
+		ljmp $0x0,$exit.2		# Reload CS
+exit.2: 	xor %ax,%ax			# Real mode segment
+		mov %ax,%ss			# Reload SS
+		mov %ax,%ds			# Address data
+		mov $0x7008,%bx			# Set real mode
+		callw setpic			#  IRQ offsets
+		lidt ivtdesc	 		# Set IVT
 /*
  * Reboot or await reset.
  */
-		sti				// Enable interrupts
-		testb $0x1,btx_hdr+0x7		// Reboot?
-exit.3:		jz exit.3			// No
-		movw $0x1234, BDA_BOOT		// Do a warm boot
-		ljmp $0xf000,$0xfff0		// reboot the machine
+		sti				# Enable interrupts
+		testb $0x1,btx_hdr+0x7		# Reboot?
+exit.3:		jz exit.3			# No
+		movw $0x1234, BDA_BOOT		# Do a warm boot
+		ljmp $0xf000,$0xfff0		# reboot the machine
 /*
  * Set IRQ offsets by reprogramming 8259A PICs.
  */
-setpic: 	in $0x21,%al			// Save master
-		push %ax			//  IMR
-		in $0xa1,%al			// Save slave
-		push %ax			//  IMR
-		movb $0x11,%al			// ICW1 to
-		outb %al,$0x20			//  master,
-		outb %al,$0xa0			//  slave
-		movb %bl,%al			// ICW2 to
-		outb %al,$0x21			//  master
-		movb %bh,%al			// ICW2 to
-		outb %al,$0xa1			//  slave
-		movb $0x4,%al			// ICW3 to
-		outb %al,$0x21			//  master
-		movb $0x2,%al			// ICW3 to
-		outb %al,$0xa1			//  slave
-		movb $0x1,%al			// ICW4 to
-		outb %al,$0x21			//  master,
-		outb %al,$0xa1			//  slave
-		pop %ax				// Restore slave
-		outb %al,$0xa1			//  IMR
-		pop %ax				// Restore master
-		outb %al,$0x21			//  IMR
-		retw				// To caller
+setpic: 	in $0x21,%al			# Save master
+		push %ax			#  IMR
+		in $0xa1,%al			# Save slave
+		push %ax			#  IMR
+		movb $0x11,%al			# ICW1 to
+		outb %al,$0x20			#  master,
+		outb %al,$0xa0			#  slave
+		movb %bl,%al			# ICW2 to
+		outb %al,$0x21			#  master
+		movb %bh,%al			# ICW2 to
+		outb %al,$0xa1			#  slave
+		movb $0x4,%al			# ICW3 to
+		outb %al,$0x21			#  master
+		movb $0x2,%al			# ICW3 to
+		outb %al,$0xa1			#  slave
+		movb $0x1,%al			# ICW4 to
+		outb %al,$0x21			#  master,
+		outb %al,$0xa1			#  slave
+		pop %ax				# Restore slave
+		outb %al,$0xa1			#  IMR
+		pop %ax				# Restore master
+		outb %al,$0x21			#  IMR
+		retw				# To caller
 		.code32
 /*
  * Initiate return from V86 mode to user mode.
  */
-inthlt: 	hlt				// To supervisor mode
+inthlt: 	hlt				# To supervisor mode
 /*
  * Exception jump table.
  */
-intx00: 	push $0x0			// Int 0x0: #DE
-		jmp ex_noc			// Divide error
-		push $0x1			// Int 0x1: #DB
-		jmp ex_noc			// Debug
-		push $0x3			// Int 0x3: #BP
-		jmp ex_noc			// Breakpoint
-		push $0x4			// Int 0x4: #OF
-		jmp ex_noc			// Overflow
-		push $0x5			// Int 0x5: #BR
-		jmp ex_noc			// BOUND range exceeded
-		push $0x6			// Int 0x6: #UD
-		jmp ex_noc			// Invalid opcode
-		push $0x7			// Int 0x7: #NM
-		jmp ex_noc			// Device not available
-		push $0x8			// Int 0x8: #DF
-		jmp except			// Double fault
-		push $0xa			// Int 0xa: #TS
-		jmp except			// Invalid TSS
-		push $0xb			// Int 0xb: #NP
-		jmp except			// Segment not present
-		push $0xc			// Int 0xc: #SS
-		jmp except			// Stack segment fault
-		push $0xd			// Int 0xd: #GP
-		jmp ex_v86			// General protection
-		push $0xe			// Int 0xe: #PF
-		jmp except			// Page fault
-intx10: 	push $0x10			// Int 0x10: #MF
-		jmp ex_noc			// Floating-point error
+intx00: 	push $0x0			# Int 0x0: #DE
+		jmp ex_noc			# Divide error
+		push $0x1			# Int 0x1: #DB
+		jmp ex_noc			# Debug
+		push $0x3			# Int 0x3: #BP
+		jmp ex_noc			# Breakpoint
+		push $0x4			# Int 0x4: #OF
+		jmp ex_noc			# Overflow
+		push $0x5			# Int 0x5: #BR
+		jmp ex_noc			# BOUND range exceeded
+		push $0x6			# Int 0x6: #UD
+		jmp ex_noc			# Invalid opcode
+		push $0x7			# Int 0x7: #NM
+		jmp ex_noc			# Device not available
+		push $0x8			# Int 0x8: #DF
+		jmp except			# Double fault
+		push $0xa			# Int 0xa: #TS
+		jmp except			# Invalid TSS
+		push $0xb			# Int 0xb: #NP
+		jmp except			# Segment not present
+		push $0xc			# Int 0xc: #SS
+		jmp except			# Stack segment fault
+		push $0xd			# Int 0xd: #GP
+		jmp ex_v86			# General protection
+		push $0xe			# Int 0xe: #PF
+		jmp except			# Page fault
+intx10: 	push $0x10			# Int 0x10: #MF
+		jmp ex_noc			# Floating-point error
 /*
  * Handle #GP exception.
  */
-ex_v86: 	testb $0x2,0x12(%esp,1) 	// V86 mode?
-		jz except			// No
-		jmp v86mon			// To monitor
+ex_v86: 	testb $0x2,0x12(%esp,1) 	# V86 mode?
+		jz except			# No
+		jmp v86mon			# To monitor
 /*
  * Save a zero error code.
  */
-ex_noc: 	pushl (%esp,1)			// Duplicate int no
-		movb $0x0,0x4(%esp,1)		// Fake error code
+ex_noc: 	pushl (%esp,1)			# Duplicate int no
+		movb $0x0,0x4(%esp,1)		# Fake error code
 /*
  * Handle exception.
  */
-except: 	cld				// String ops inc
-		pushl %ds			// Save
-		pushl %es			//  most
-		pusha				//  registers
-		movb $0x6,%al			// Push loop count
-		testb $0x2,0x3a(%esp,1) 	// V86 mode?
-		jnz except.1			// Yes
-		pushl %gs			// Set GS
-		pushl %fs			// Set FS
-		pushl %ds			// Set DS
-		pushl %es			// Set ES
-		movb $0x2,%al			// Push loop count
-		cmpw $SEL_SCODE,0x44(%esp,1)	// Supervisor mode?
-		jne except.1			// No
-		pushl %ss			// Set SS
-		leal 0x50(%esp,1),%eax		// Set
-		pushl %eax			//  ESP
-		jmp except.2			// Join common code
-except.1:	pushl 0x50(%esp,1)		// Set GS, FS, DS, ES
-		decb %al			//  (if V86 mode), and
-		jne except.1			//  SS, ESP
-except.2:	push $SEL_SDATA			// Set up
-		popl %ds			//  to
-		pushl %ds			//  address
-		popl %es			//  data
-		movl %esp,%ebx			// Stack frame
-		movl $dmpfmt,%esi		// Dump format string
-		movl $MEM_BUF,%edi		// Buffer
-		pushl %edi			// Dump to
-		call dump			//  buffer
-		popl %esi			//  and
-		call putstr			//  display
-		leal 0x18(%esp,1),%esp		// Discard frame
-		popa				// Restore
-		popl %es			//  registers
-		popl %ds			//  saved
-		cmpb $0x3,(%esp,1)		// Breakpoint?
-		je except.3			// Yes
-		cmpb $0x1,(%esp,1)		// Debug?
-		jne except.2a			// No
-		testl $0x100,0x10(%esp,1)	// Trap flag set?
-		jnz except.3			// Yes
-except.2a:	jmp exit			// Exit
-except.3:	leal 0x8(%esp,1),%esp		// Discard err, int no
-		iret				// From interrupt
+except: 	cld				# String ops inc
+		pushl %ds			# Save
+		pushl %es			#  most
+		pusha				#  registers
+		movb $0x6,%al			# Push loop count
+		testb $0x2,0x3a(%esp,1) 	# V86 mode?
+		jnz except.1			# Yes
+		pushl %gs			# Set GS
+		pushl %fs			# Set FS
+		pushl %ds			# Set DS
+		pushl %es			# Set ES
+		movb $0x2,%al			# Push loop count
+		cmpw $SEL_SCODE,0x44(%esp,1)	# Supervisor mode?
+		jne except.1			# No
+		pushl %ss			# Set SS
+		leal 0x50(%esp,1),%eax		# Set
+		pushl %eax			#  ESP
+		jmp except.2			# Join common code
+except.1:	pushl 0x50(%esp,1)		# Set GS, FS, DS, ES
+		decb %al			#  (if V86 mode), and
+		jne except.1			#  SS, ESP
+except.2:	push $SEL_SDATA			# Set up
+		popl %ds			#  to
+		pushl %ds			#  address
+		popl %es			#  data
+		movl %esp,%ebx			# Stack frame
+		movl $dmpfmt,%esi		# Dump format string
+		movl $MEM_BUF,%edi		# Buffer
+		pushl %edi			# Dump to
+		call dump			#  buffer
+		popl %esi			#  and
+		call putstr			#  display
+		leal 0x18(%esp,1),%esp		# Discard frame
+		popa				# Restore
+		popl %es			#  registers
+		popl %ds			#  saved
+		cmpb $0x3,(%esp,1)		# Breakpoint?
+		je except.3			# Yes
+		cmpb $0x1,(%esp,1)		# Debug?
+		jne except.2a			# No
+		testl $0x100,0x10(%esp,1)	# Trap flag set?
+		jnz except.3			# Yes
+except.2a:	jmp exit			# Exit
+except.3:	leal 0x8(%esp,1),%esp		# Discard err, int no
+		iret				# From interrupt
 /*
  * Return to user mode from V86 mode.
  */
-intrtn: 	cld				// String ops inc
-		pushl %ds			// Address
-		popl %es			//  data
-		leal 0x3c(%ebp),%edx		// V86 Segment registers
-		movl MEM_TSS+TSS_ESP1,%esi	// Link stack pointer
-		lodsl				// INT_V86 args pointer
-		movl %esi,%ebx			// Saved exception frame
-		testl %eax,%eax 		// INT_V86 args?
-		jz intrtn.2			// No
-		movl $MEM_USR,%edi		// User base
-		movl 0x1c(%esi),%ebx		// User ESP
-		movl %eax,(%edi,%ebx,1) 	// Restore to user stack
-		leal 0x8(%edi,%eax,1),%edi	// Arg segment registers
-		testb $0x4,-0x6(%edi)		// Return flags?
-		jz intrtn.1			// No
-		movl 0x30(%ebp),%eax		// Get V86 flags
-		movw %ax,0x18(%esi)		// Set user flags
-intrtn.1:	leal 0x10(%esi),%ebx		// Saved exception frame
-		xchgl %edx,%esi 		// Segment registers
-		movb $0x4,%cl			// Update seg regs
-		rep				//  in INT_V86
-		movsl				//  args
-intrtn.2:	movl %edx,%esi			// Segment registers
-		leal 0x28(%ebp),%edi		// Set up seg
-		movb $0x4,%cl			//  regs for
-		rep				//  later
-		movsl				//  pop
-		movl %ebx,%esi			// Restore exception
-		movb $0x5,%cl			//  frame to
-		rep				//  supervisor
-		movsl				//  stack
-		movl %esi,MEM_TSS+TSS_ESP1	// Link stack pointer
-		popa				// Restore
-		leal 0x8(%esp,1),%esp		// Discard err, int no
-		popl %es			// Restore
-		popl %ds			//  user
-		popl %fs			//  segment
-		popl %gs			//  registers
-		iret				// To user mode
+intrtn: 	cld				# String ops inc
+		pushl %ds			# Address
+		popl %es			#  data
+		leal 0x3c(%ebp),%edx		# V86 Segment registers
+		movl MEM_TSS+TSS_ESP1,%esi	# Link stack pointer
+		lodsl				# INT_V86 args pointer
+		movl %esi,%ebx			# Saved exception frame
+		testl %eax,%eax 		# INT_V86 args?
+		jz intrtn.2			# No
+		movl $MEM_USR,%edi		# User base
+		movl 0x1c(%esi),%ebx		# User ESP
+		movl %eax,(%edi,%ebx,1) 	# Restore to user stack
+		leal 0x8(%edi,%eax,1),%edi	# Arg segment registers
+		testb $0x4,-0x6(%edi)		# Return flags?
+		jz intrtn.1			# No
+		movl 0x30(%ebp),%eax		# Get V86 flags
+		movw %ax,0x18(%esi)		# Set user flags
+intrtn.1:	leal 0x10(%esi),%ebx		# Saved exception frame
+		xchgl %edx,%esi 		# Segment registers
+		movb $0x4,%cl			# Update seg regs
+		rep				#  in INT_V86
+		movsl				#  args
+intrtn.2:	movl %edx,%esi			# Segment registers
+		leal 0x28(%ebp),%edi		# Set up seg
+		movb $0x4,%cl			#  regs for
+		rep				#  later
+		movsl				#  pop
+		movl %ebx,%esi			# Restore exception
+		movb $0x5,%cl			#  frame to
+		rep				#  supervisor
+		movsl				#  stack
+		movl %esi,MEM_TSS+TSS_ESP1	# Link stack pointer
+		popa				# Restore
+		leal 0x8(%esp,1),%esp		# Discard err, int no
+		popl %es			# Restore
+		popl %ds			#  user
+		popl %fs			#  segment
+		popl %gs			#  registers
+		iret				# To user mode
 /*
  * V86 monitor.
  */
-v86mon: 	cld				// String ops inc
-		pushl $SEL_SDATA		// Set up for
-		popl %ds			//  flat addressing
-		pusha				// Save registers
-		movl %esp,%ebp			// Address stack frame
-		movzwl 0x2c(%ebp),%edi		// Load V86 CS
-		shll $0x4,%edi			// To linear
-		movl 0x28(%ebp),%esi		// Load V86 IP
-		addl %edi,%esi			// Code pointer
-		xorl %ecx,%ecx			// Zero
-		movb $0x2,%cl			// 16-bit operands
-		xorl %eax,%eax			// Zero
-v86mon.1:	lodsb				// Get opcode
-		cmpb $0x66,%al			// Operand size prefix?
-		jne v86mon.2			// No
-		movb $0x4,%cl			// 32-bit operands
-		jmp v86mon.1			// Continue
-v86mon.2:	cmpb $0xf4,%al			// HLT?
-		jne v86mon.3			// No
-		cmpl $inthlt+0x1,%esi		// Is inthlt?
-		jne v86mon.7			// No (ignore)
-		jmp intrtn			// Return to user mode
-v86mon.3:	cmpb $0xf,%al			// Prefixed instruction?
-		jne v86mon.4			// No
-		cmpb $0x09,(%esi)		// Is it a WBINVD?
-		je v86wbinvd			// Yes
-		cmpb $0x30,(%esi)		// Is it a WRMSR?
-		je v86wrmsr			// Yes
-		cmpb $0x32,(%esi)		// Is it a RDMSR?
-		je v86rdmsr			// Yes
-		cmpb $0x20,(%esi)		// Is this a
-		jne v86mon.4			//  MOV EAX,CR0
-		cmpb $0xc0,0x1(%esi)		//  instruction?
-		je v86mov			// Yes
-v86mon.4:	cmpb $0xfa,%al			// CLI?
-		je v86cli			// Yes
-		cmpb $0xfb,%al			// STI?
-		je v86sti			// Yes
-		movzwl 0x38(%ebp),%ebx		// Load V86 SS
-		shll $0x4,%ebx			// To offset
-		pushl %ebx			// Save
-		addl 0x34(%ebp),%ebx		// Add V86 SP
-		movl 0x30(%ebp),%edx		// Load V86 flags
-		cmpb $0x9c,%al			// PUSHF/PUSHFD?
-		je v86pushf			// Yes
-		cmpb $0x9d,%al			// POPF/POPFD?
-		je v86popf			// Yes
-		cmpb $0xcd,%al			// INT imm8?
-		je v86intn			// Yes
-		cmpb $0xcf,%al			// IRET/IRETD?
-		je v86iret			// Yes
-		popl %ebx			// Restore
-		popa				// Restore
-		jmp except			// Handle exception
-v86mon.5:	movl %edx,0x30(%ebp)		// Save V86 flags
-v86mon.6:	popl %edx			// V86 SS adjustment
-		subl %edx,%ebx			// Save V86
-		movl %ebx,0x34(%ebp)		//  SP
-v86mon.7:	subl %edi,%esi			// From linear
-		movl %esi,0x28(%ebp)		// Save V86 IP
-		popa				// Restore
-		leal 0x8(%esp,1),%esp		// Discard int no, error
-		iret				// To V86 mode
+v86mon: 	cld				# String ops inc
+		pushl $SEL_SDATA		# Set up for
+		popl %ds			#  flat addressing
+		pusha				# Save registers
+		movl %esp,%ebp			# Address stack frame
+		movzwl 0x2c(%ebp),%edi		# Load V86 CS
+		shll $0x4,%edi			# To linear
+		movl 0x28(%ebp),%esi		# Load V86 IP
+		addl %edi,%esi			# Code pointer
+		xorl %ecx,%ecx			# Zero
+		movb $0x2,%cl			# 16-bit operands
+		xorl %eax,%eax			# Zero
+v86mon.1:	lodsb				# Get opcode
+		cmpb $0x66,%al			# Operand size prefix?
+		jne v86mon.2			# No
+		movb $0x4,%cl			# 32-bit operands
+		jmp v86mon.1			# Continue
+v86mon.2:	cmpb $0xf4,%al			# HLT?
+		jne v86mon.3			# No
+		cmpl $inthlt+0x1,%esi		# Is inthlt?
+		jne v86mon.7			# No (ignore)
+		jmp intrtn			# Return to user mode
+v86mon.3:	cmpb $0xf,%al			# Prefixed instruction?
+		jne v86mon.4			# No
+		cmpb $0x09,(%esi)		# Is it a WBINVD?
+		je v86wbinvd			# Yes
+		cmpb $0x30,(%esi)		# Is it a WRMSR?
+		je v86wrmsr			# Yes
+		cmpb $0x32,(%esi)		# Is it a RDMSR?
+		je v86rdmsr			# Yes
+		cmpb $0x20,(%esi)		# Is this a
+		jne v86mon.4			#  MOV EAX,CR0
+		cmpb $0xc0,0x1(%esi)		#  instruction?
+		je v86mov			# Yes
+v86mon.4:	cmpb $0xfa,%al			# CLI?
+		je v86cli			# Yes
+		cmpb $0xfb,%al			# STI?
+		je v86sti			# Yes
+		movzwl 0x38(%ebp),%ebx		# Load V86 SS
+		shll $0x4,%ebx			# To offset
+		pushl %ebx			# Save
+		addl 0x34(%ebp),%ebx		# Add V86 SP
+		movl 0x30(%ebp),%edx		# Load V86 flags
+		cmpb $0x9c,%al			# PUSHF/PUSHFD?
+		je v86pushf			# Yes
+		cmpb $0x9d,%al			# POPF/POPFD?
+		je v86popf			# Yes
+		cmpb $0xcd,%al			# INT imm8?
+		je v86intn			# Yes
+		cmpb $0xcf,%al			# IRET/IRETD?
+		je v86iret			# Yes
+		popl %ebx			# Restore
+		popa				# Restore
+		jmp except			# Handle exception
+v86mon.5:	movl %edx,0x30(%ebp)		# Save V86 flags
+v86mon.6:	popl %edx			# V86 SS adjustment
+		subl %edx,%ebx			# Save V86
+		movl %ebx,0x34(%ebp)		#  SP
+v86mon.7:	subl %edi,%esi			# From linear
+		movl %esi,0x28(%ebp)		# Save V86 IP
+		popa				# Restore
+		leal 0x8(%esp,1),%esp		# Discard int no, error
+		iret				# To V86 mode
 /*
  * Emulate MOV EAX,CR0.
  */
-v86mov: 	movl %cr0,%eax			// CR0 to
-		movl %eax,0x1c(%ebp)		//  saved EAX
-		incl %esi			// Adjust IP
+v86mov: 	movl %cr0,%eax			# CR0 to
+		movl %eax,0x1c(%ebp)		#  saved EAX
+		incl %esi			# Adjust IP
 /*
  * Return from emulating a 0x0f prefixed instruction
  */
-v86preret:	incl %esi			// Adjust IP
-		jmp v86mon.7			// Finish up
+v86preret:	incl %esi			# Adjust IP
+		jmp v86mon.7			# Finish up
 /*
  * Emulate WBINVD
  */
-v86wbinvd:	wbinvd				// Write back and invalidate
-						//  cache
-		jmp v86preret			// Finish up
+v86wbinvd:	wbinvd				# Write back and invalidate
+						#  cache
+		jmp v86preret			# Finish up
 /*
  * Emulate WRMSR
  */
-v86wrmsr:	movl 0x18(%ebp),%ecx		// Get user's %ecx
-						//  (MSR to write)
-		movl 0x14(%ebp),%edx		// Load the value
-		movl 0x1c(%ebp),%eax		//  to write
-		wrmsr				// Write MSR
-		jmp v86preret			// Finish up
+v86wrmsr:	movl 0x18(%ebp),%ecx		# Get user's %ecx (MSR to write)
+		movl 0x14(%ebp),%edx		# Load the value
+		movl 0x1c(%ebp),%eax		#  to write
+		wrmsr				# Write MSR
+		jmp v86preret			# Finish up
 /*
  * Emulate RDMSR
  */
-v86rdmsr:	movl 0x18(%ebp),%ecx		// MSR to read
-		rdmsr				// Read the MSR
-		movl %eax,0x1c(%ebp)		// Return the value of
-		movl %edx,0x14(%ebp)		//  the MSR to the user
-		jmp v86preret			// Finish up
+v86rdmsr:	movl 0x18(%ebp),%ecx		# MSR to read
+		rdmsr				# Read the MSR
+		movl %eax,0x1c(%ebp)		# Return the value of
+		movl %edx,0x14(%ebp)		#  the MSR to the user
+		jmp v86preret			# Finish up
 /*
  * Emulate CLI.
  */
-v86cli: 	andb $~0x2,0x31(%ebp)		// Clear IF
-		jmp v86mon.7			// Finish up
+v86cli: 	andb $~0x2,0x31(%ebp)		# Clear IF
+		jmp v86mon.7			# Finish up
 /*
  * Emulate STI.
  */
-v86sti: 	orb $0x2,0x31(%ebp)		// Set IF
-		jmp v86mon.7			// Finish up
+v86sti: 	orb $0x2,0x31(%ebp)		# Set IF
+		jmp v86mon.7			# Finish up
 /*
  * Emulate PUSHF/PUSHFD.
  */
-v86pushf:	subl %ecx,%ebx			// Adjust SP
-		cmpb $0x4,%cl			// 32-bit
-		je v86pushf.1			// Yes
-		data16				// 16-bit
-v86pushf.1:	movl %edx,(%ebx)		// Save flags
-		jmp v86mon.6			// Finish up
+v86pushf:	subl %ecx,%ebx			# Adjust SP
+		cmpb $0x4,%cl			# 32-bit
+		je v86pushf.1			# Yes
+		data16				# 16-bit
+v86pushf.1:	movl %edx,(%ebx)		# Save flags
+		jmp v86mon.6			# Finish up
 /*
  * Emulate IRET/IRETD.
  */
-v86iret:	movzwl (%ebx),%esi		// Load V86 IP
-		movzwl 0x2(%ebx),%edi		// Load V86 CS
-		leal 0x4(%ebx),%ebx		// Adjust SP
-		movl %edi,0x2c(%ebp)		// Save V86 CS
-		xorl %edi,%edi			// No ESI adjustment
+v86iret:	movzwl (%ebx),%esi		# Load V86 IP
+		movzwl 0x2(%ebx),%edi		# Load V86 CS
+		leal 0x4(%ebx),%ebx		# Adjust SP
+		movl %edi,0x2c(%ebp)		# Save V86 CS
+		xorl %edi,%edi			# No ESI adjustment
 /*
  * Emulate POPF/POPFD (and remainder of IRET/IRETD).
  */
-v86popf:	cmpb $0x4,%cl			// 32-bit?
-		je v86popf.1			// Yes
-		movl %edx,%eax			// Initialize
-		data16				// 16-bit
-v86popf.1:	movl (%ebx),%eax		// Load flags
-		addl %ecx,%ebx			// Adjust SP
-		andl $V86_FLG,%eax		// Merge
-		andl $~V86_FLG,%edx		//  the
-		orl %eax,%edx			//  flags
-		jmp v86mon.5			// Finish up
+v86popf:	cmpb $0x4,%cl			# 32-bit?
+		je v86popf.1			# Yes
+		movl %edx,%eax			# Initialize
+		data16				# 16-bit
+v86popf.1:	movl (%ebx),%eax		# Load flags
+		addl %ecx,%ebx			# Adjust SP
+		andl $V86_FLG,%eax		# Merge
+		andl $~V86_FLG,%edx		#  the
+		orl %eax,%edx			#  flags
+		jmp v86mon.5			# Finish up
 /*
  * trap int 15, function 87
  * reads %es:%si from saved registers on stack to find a GDT containing
@@ -607,566 +606,566 @@ v86popf.1:	movl (%ebx),%eax		// Load flags
  * reads count of words from saved %cx
  * returns success by setting %ah to 0
  */
-int15_87:	pushl %eax			// Save
-		pushl %ebx			//  some information
-		pushl %esi			//  onto the stack.
+int15_87:	pushl %eax			# Save
+		pushl %ebx			#  some information
+		pushl %esi			#  onto the stack.
 		pushl %edi
-		xorl %eax,%eax			// clean EAX
-		xorl %ebx,%ebx			// clean EBX
-		movl 0x4(%ebp),%esi		// Get user's ESI
-		movl 0x3C(%ebp),%ebx		// store ES
-		movw %si,%ax			// store SI
-		shll $0x4,%ebx			// Make it a seg.
-		addl %eax,%ebx			// ebx=(es<<4)+si
-		movb 0x14(%ebx),%al		// Grab the
-		movb 0x17(%ebx),%ah		//  necessary
-		shll $0x10,%eax			//  information
-		movw 0x12(%ebx),%ax		//  from
-		movl %eax,%esi			//  the
-		movb 0x1c(%ebx),%al		//  GDT in order to
-		movb 0x1f(%ebx),%ah		//  have %esi offset
-		shll $0x10,%eax			//  of source and %edi
-		movw 0x1a(%ebx),%ax		//  of destination.
+		xorl %eax,%eax			# clean EAX
+		xorl %ebx,%ebx			# clean EBX
+		movl 0x4(%ebp),%esi		# Get user's ESI
+		movl 0x3C(%ebp),%ebx		# store ES
+		movw %si,%ax			# store SI
+		shll $0x4,%ebx			# Make it a seg.
+		addl %eax,%ebx			# ebx=(es<<4)+si
+		movb 0x14(%ebx),%al		# Grab the
+		movb 0x17(%ebx),%ah		#  necessary
+		shll $0x10,%eax			#  information
+		movw 0x12(%ebx),%ax		#  from
+		movl %eax,%esi			#  the
+		movb 0x1c(%ebx),%al		#  GDT in order to
+		movb 0x1f(%ebx),%ah		#  have %esi offset
+		shll $0x10,%eax			#  of source and %edi
+		movw 0x1a(%ebx),%ax		#  of destination.
 		movl %eax,%edi
-		pushl %ds			// Make:
-		popl %es			// es = ds
-		pushl %ecx			// stash ECX
-		xorl %ecx,%ecx			// highw of ECX is clear
-		movw 0x18(%ebp),%cx		// Get user's ECX
-		shll $0x1,%ecx			// Convert from num words to num
-						//  bytes
-		rep				// repeat...
-		movsb				//  perform copy.
-		popl %ecx			// Restore
+		pushl %ds			# Make:
+		popl %es			# es = ds
+		pushl %ecx			# stash ECX
+		xorl %ecx,%ecx			# highw of ECX is clear
+		movw 0x18(%ebp),%cx		# Get user's ECX
+		shll $0x1,%ecx			# Convert from num words to num
+						#  bytes
+		rep				# repeat...
+		movsb				#  perform copy.
+		popl %ecx			# Restore
 		popl %edi
-		popl %esi			//  previous
-		popl %ebx			//  register
-		popl %eax			//  values.
-		movb $0x0,0x1d(%ebp)		// set ah = 0 to indicate
-						//  success
-		andb $0xfe,%dl			// clear CF
-		jmp v86mon.5			// Finish up
+		popl %esi			#  previous
+		popl %ebx			#  register
+		popl %eax			#  values.
+		movb $0x0,0x1d(%ebp)		# set ah = 0 to indicate
+						#  success
+		andb $0xfe,%dl			# clear CF
+		jmp v86mon.5			# Finish up
 
 /*
  * Reboot the machine by setting the reboot flag and exiting
  */
-reboot:		orb $0x1,btx_hdr+0x7		// Set the reboot flag
-		jmp exit			// Terminate BTX and reboot
+reboot:		orb $0x1,btx_hdr+0x7		# Set the reboot flag
+		jmp exit			# Terminate BTX and reboot
 
 /*
  * Emulate INT imm8... also make sure to check if it's int 15/87
  */
-v86intn:	lodsb				// Get int no
-		cmpb $0x19,%al			// is it int 19?
-		je reboot			//  yes, reboot the machine
-		cmpb $0x15,%al			// is it int 15?
-		jne v86intn.3			//  no, skip parse
-		pushl %eax                      // stash EAX
-		movl 0x1c(%ebp),%eax		// user's saved EAX
-		cmpb $0x87,%ah			// is it the memcpy subfunction?
-		jne v86intn.1			//  no, keep checking
-		popl %eax			// get the stack straight
-		jmp int15_87			// it's our cue
-v86intn.1:	cmpw $0x4f53,%ax		// is it the delete key callout?
-		jne v86intn.2			//  no, handle the int normally
-		movb BDA_KEYFLAGS,%al		// get the shift key state
-		andb $0xc,%al			// mask off just Ctrl and Alt
-		cmpb $0xc,%al			// are both Ctrl and Alt down?
-		jne v86intn.2			//  no, handle the int normally
-		popl %eax			// restore EAX
-		jmp reboot			// reboot the machine
-v86intn.2:	popl %eax			// restore EAX
-v86intn.3:	subl %edi,%esi			// From
-		shrl $0x4,%edi			//  linear
-		movw %dx,-0x2(%ebx)		// Save flags
-		movw %di,-0x4(%ebx)		// Save CS
-		leal -0x6(%ebx),%ebx		// Adjust SP
-		movw %si,(%ebx) 		// Save IP
-		shll $0x2,%eax			// Scale
-		movzwl (%eax),%esi		// Load IP
-		movzwl 0x2(%eax),%edi		// Load CS
-		movl %edi,0x2c(%ebp)		// Save CS
-		xorl %edi,%edi			// No ESI adjustment
-		andb $~0x1,%dh			// Clear TF
-		jmp v86mon.5			// Finish up
+v86intn:	lodsb				# Get int no
+		cmpb $0x19,%al			# is it int 19?
+		je reboot			#  yes, reboot the machine
+		cmpb $0x15,%al			# is it int 15?
+		jne v86intn.3			#  no, skip parse
+		pushl %eax                      # stash EAX
+		movl 0x1c(%ebp),%eax		# user's saved EAX
+		cmpb $0x87,%ah			# is it the memcpy subfunction?
+		jne v86intn.1			#  no, keep checking
+		popl %eax			# get the stack straight
+		jmp int15_87			# it's our cue
+v86intn.1:	cmpw $0x4f53,%ax		# is it the delete key callout?
+		jne v86intn.2			#  no, handle the int normally
+		movb BDA_KEYFLAGS,%al		# get the shift key state
+		andb $0xc,%al			# mask off just Ctrl and Alt
+		cmpb $0xc,%al			# are both Ctrl and Alt down?
+		jne v86intn.2			#  no, handle the int normally
+		popl %eax			# restore EAX
+		jmp reboot			# reboot the machine
+v86intn.2:	popl %eax			# restore EAX
+v86intn.3:	subl %edi,%esi			# From
+		shrl $0x4,%edi			#  linear
+		movw %dx,-0x2(%ebx)		# Save flags
+		movw %di,-0x4(%ebx)		# Save CS
+		leal -0x6(%ebx),%ebx		# Adjust SP
+		movw %si,(%ebx) 		# Save IP
+		shll $0x2,%eax			# Scale
+		movzwl (%eax),%esi		# Load IP
+		movzwl 0x2(%eax),%edi		# Load CS
+		movl %edi,0x2c(%ebp)		# Save CS
+		xorl %edi,%edi			# No ESI adjustment
+		andb $~0x1,%dh			# Clear TF
+		jmp v86mon.5			# Finish up
 /*
  * Hardware interrupt jump table.
  */
-intx20: 	push $0x8			// Int 0x20: IRQ0
-		jmp int_hw			// V86 int 0x8
-		push $0x9			// Int 0x21: IRQ1
-		jmp int_hw			// V86 int 0x9
-		push $0xa			// Int 0x22: IRQ2
-		jmp int_hw			// V86 int 0xa
-		push $0xb			// Int 0x23: IRQ3
-		jmp int_hw			// V86 int 0xb
-		push $0xc			// Int 0x24: IRQ4
-		jmp int_hw			// V86 int 0xc
-		push $0xd			// Int 0x25: IRQ5
-		jmp int_hw			// V86 int 0xd
-		push $0xe			// Int 0x26: IRQ6
-		jmp int_hw			// V86 int 0xe
-		push $0xf			// Int 0x27: IRQ7
-		jmp int_hw			// V86 int 0xf
-		push $0x70			// Int 0x28: IRQ8
-		jmp int_hw			// V86 int 0x70
-		push $0x71			// Int 0x29: IRQ9
-		jmp int_hw			// V86 int 0x71
-		push $0x72			// Int 0x2a: IRQ10
-		jmp int_hw			// V86 int 0x72
-		push $0x73			// Int 0x2b: IRQ11
-		jmp int_hw			// V86 int 0x73
-		push $0x74			// Int 0x2c: IRQ12
-		jmp int_hw			// V86 int 0x74
-		push $0x75			// Int 0x2d: IRQ13
-		jmp int_hw			// V86 int 0x75
-		push $0x76			// Int 0x2e: IRQ14
-		jmp int_hw			// V86 int 0x76
-		push $0x77			// Int 0x2f: IRQ15
-		jmp int_hw			// V86 int 0x77
+intx20: 	push $0x8			# Int 0x20: IRQ0
+		jmp int_hw			# V86 int 0x8
+		push $0x9			# Int 0x21: IRQ1
+		jmp int_hw			# V86 int 0x9
+		push $0xa			# Int 0x22: IRQ2
+		jmp int_hw			# V86 int 0xa
+		push $0xb			# Int 0x23: IRQ3
+		jmp int_hw			# V86 int 0xb
+		push $0xc			# Int 0x24: IRQ4
+		jmp int_hw			# V86 int 0xc
+		push $0xd			# Int 0x25: IRQ5
+		jmp int_hw			# V86 int 0xd
+		push $0xe			# Int 0x26: IRQ6
+		jmp int_hw			# V86 int 0xe
+		push $0xf			# Int 0x27: IRQ7
+		jmp int_hw			# V86 int 0xf
+		push $0x70			# Int 0x28: IRQ8
+		jmp int_hw			# V86 int 0x70
+		push $0x71			# Int 0x29: IRQ9
+		jmp int_hw			# V86 int 0x71
+		push $0x72			# Int 0x2a: IRQ10
+		jmp int_hw			# V86 int 0x72
+		push $0x73			# Int 0x2b: IRQ11
+		jmp int_hw			# V86 int 0x73
+		push $0x74			# Int 0x2c: IRQ12
+		jmp int_hw			# V86 int 0x74
+		push $0x75			# Int 0x2d: IRQ13
+		jmp int_hw			# V86 int 0x75
+		push $0x76			# Int 0x2e: IRQ14
+		jmp int_hw			# V86 int 0x76
+		push $0x77			# Int 0x2f: IRQ15
+		jmp int_hw			# V86 int 0x77
 /*
  * Reflect hardware interrupts.
  */
-int_hw: 	testb $0x2,0xe(%esp,1)		// V86 mode?
-		jz intusr			// No
-		pushl $SEL_SDATA		// Address
-		popl %ds			//  data
-		xchgl %eax,(%esp,1)		// Swap EAX, int no
-		pushl %ebp			// Address
-		movl %esp,%ebp			//  stack frame
-		pushl %ebx			// Save
-		shll $0x2,%eax			// Get int
-		movl (%eax),%eax		//  vector
-		subl $0x6,0x14(%ebp)		// Adjust V86 ESP
-		movzwl 0x18(%ebp),%ebx		// V86 SS
-		shll $0x4,%ebx			//  * 0x10
-		addl 0x14(%ebp),%ebx		//  + V86 ESP
-		xchgw %ax,0x8(%ebp)		// Swap V86 IP
-		rorl $0x10,%eax 		// Swap words
-		xchgw %ax,0xc(%ebp)		// Swap V86 CS
-		roll $0x10,%eax 		// Swap words
-		movl %eax,(%ebx)		// CS:IP for IRET
-		movl 0x10(%ebp),%eax		// V86 flags
-		movw %ax,0x4(%ebx)		// Flags for IRET
-		andb $~0x3,0x11(%ebp)		// Clear IF, TF
-		popl %ebx			// Restore
-		popl %ebp			//  saved
-		popl %eax			//  registers
-		iret				// To V86 mode
+int_hw: 	testb $0x2,0xe(%esp,1)		# V86 mode?
+		jz intusr			# No
+		pushl $SEL_SDATA		# Address
+		popl %ds			#  data
+		xchgl %eax,(%esp,1)		# Swap EAX, int no
+		pushl %ebp			# Address
+		movl %esp,%ebp			#  stack frame
+		pushl %ebx			# Save
+		shll $0x2,%eax			# Get int
+		movl (%eax),%eax		#  vector
+		subl $0x6,0x14(%ebp)		# Adjust V86 ESP
+		movzwl 0x18(%ebp),%ebx		# V86 SS
+		shll $0x4,%ebx			#  * 0x10
+		addl 0x14(%ebp),%ebx		#  + V86 ESP
+		xchgw %ax,0x8(%ebp)		# Swap V86 IP
+		rorl $0x10,%eax 		# Swap words
+		xchgw %ax,0xc(%ebp)		# Swap V86 CS
+		roll $0x10,%eax 		# Swap words
+		movl %eax,(%ebx)		# CS:IP for IRET
+		movl 0x10(%ebp),%eax		# V86 flags
+		movw %ax,0x4(%ebx)		# Flags for IRET
+		andb $~0x3,0x11(%ebp)		# Clear IF, TF
+		popl %ebx			# Restore
+		popl %ebp			#  saved
+		popl %eax			#  registers
+		iret				# To V86 mode
 /*
  * Invoke V86 interrupt from user mode, with arguments.
  */
-intx31: 	stc				// Have btx_v86
-		pushl %eax			// Missing int no
+intx31: 	stc				# Have btx_v86
+		pushl %eax			# Missing int no
 /*
  * Invoke V86 interrupt from user mode.
  */
-intusr: 	std				// String ops dec
-		pushl %eax			// Expand
-		pushl %eax			//  stack
-		pushl %eax			//  frame
-		pusha				// Save
-		pushl %gs			// Save
-		movl %esp,%eax			//  seg regs
-		pushl %fs			//  and
-		pushl %ds			//  point
-		pushl %es			//  to them
-		push $SEL_SDATA			// Set up
-		popl %ds			//  to
-		pushl %ds			//  address
-		popl %es			//  data
-		movl $MEM_USR,%ebx		// User base
-		movl %ebx,%edx			//  address
-		jc intusr.1			// If btx_v86
-		xorl %edx,%edx			// Control flags
-		xorl %ebp,%ebp			// btx_v86 pointer
-intusr.1:	leal 0x50(%esp,1),%esi		// Base of frame
-		pushl %esi			// Save
-		addl -0x4(%esi),%ebx		// User ESP
-		movl MEM_TSS+TSS_ESP1,%edi	// Link stack pointer
-		leal -0x4(%edi),%edi		// Adjust for push
-		xorl %ecx,%ecx			// Zero
-		movb $0x5,%cl			// Push exception
-		rep				//  frame on
-		movsl				//  link stack
-		xchgl %eax,%esi 		// Saved seg regs
-		movl 0x40(%esp,1),%eax		// Get int no
-		testl %edx,%edx 		// Have btx_v86?
-		jz intusr.2			// No
-		movl (%ebx),%ebp		// btx_v86 pointer
-		movb $0x4,%cl			// Count
-		addl %ecx,%ebx			// Adjust for pop
-		rep				// Push saved seg regs
-		movsl				//  on link stack
-		addl %ebp,%edx			// Flatten btx_v86 ptr
-		leal 0x14(%edx),%esi		// Seg regs pointer
-		movl 0x4(%edx),%eax		// Get int no/address
-		movzwl 0x2(%edx),%edx		// Get control flags
-intusr.2:	movl %ebp,(%edi)		// Push btx_v86 and
-		movl %edi,MEM_TSS+TSS_ESP1	//  save link stack ptr
-		popl %edi			// Base of frame
-		xchgl %eax,%ebp 		// Save intno/address
-		movl 0x48(%esp,1),%eax		// Get flags
-		testb $0x2,%dl			// Simulate CALLF?
-		jnz intusr.3			// Yes
-		decl %ebx			// Push flags
-		decl %ebx			//  on V86
-		movw %ax,(%ebx) 		//  stack
-intusr.3:	movb $0x4,%cl			// Count
-		subl %ecx,%ebx			// Push return address
-		movl $inthlt,(%ebx)		//  on V86 stack
-		rep				// Copy seg regs to
-		movsl				//  exception frame
-		xchgl %eax,%ecx 		// Save flags
-		movl %ebx,%eax			// User ESP
-		subl $V86_STK,%eax		// Less bytes
-		ja intusr.4			//  to
-		xorl %eax,%eax			//  keep
-intusr.4:	shrl $0x4,%eax			// Gives segment
-		stosl				// Set SS
-		shll $0x4,%eax			// To bytes
-		xchgl %eax,%ebx 		// Swap
-		subl %ebx,%eax			// Gives offset
-		stosl				// Set ESP
-		xchgl %eax,%ecx 		// Get flags
-		btsl $0x11,%eax 		// Set VM
-		andb $~0x1,%ah			// Clear TF
-		stosl				// Set EFL
-		xchgl %eax,%ebp 		// Get int no/address
-		testb $0x1,%dl			// Address?
-		jnz intusr.5			// Yes
-		shll $0x2,%eax			// Scale
-		movl (%eax),%eax		// Load int vector
-intusr.5:	movl %eax,%ecx			// Save
-		shrl $0x10,%eax 		// Gives segment
-		stosl				// Set CS
-		movw %cx,%ax			// Restore
-		stosl				// Set EIP
-		leal 0x10(%esp,1),%esp		// Discard seg regs
-		popa				// Restore
-		iret				// To V86 mode
+intusr: 	std				# String ops dec
+		pushl %eax			# Expand
+		pushl %eax			#  stack
+		pushl %eax			#  frame
+		pusha				# Save
+		pushl %gs			# Save
+		movl %esp,%eax			#  seg regs
+		pushl %fs			#  and
+		pushl %ds			#  point
+		pushl %es			#  to them
+		push $SEL_SDATA			# Set up
+		popl %ds			#  to
+		pushl %ds			#  address
+		popl %es			#  data
+		movl $MEM_USR,%ebx		# User base
+		movl %ebx,%edx			#  address
+		jc intusr.1			# If btx_v86
+		xorl %edx,%edx			# Control flags
+		xorl %ebp,%ebp			# btx_v86 pointer
+intusr.1:	leal 0x50(%esp,1),%esi		# Base of frame
+		pushl %esi			# Save
+		addl -0x4(%esi),%ebx		# User ESP
+		movl MEM_TSS+TSS_ESP1,%edi	# Link stack pointer
+		leal -0x4(%edi),%edi		# Adjust for push
+		xorl %ecx,%ecx			# Zero
+		movb $0x5,%cl			# Push exception
+		rep				#  frame on
+		movsl				#  link stack
+		xchgl %eax,%esi 		# Saved seg regs
+		movl 0x40(%esp,1),%eax		# Get int no
+		testl %edx,%edx 		# Have btx_v86?
+		jz intusr.2			# No
+		movl (%ebx),%ebp		# btx_v86 pointer
+		movb $0x4,%cl			# Count
+		addl %ecx,%ebx			# Adjust for pop
+		rep				# Push saved seg regs
+		movsl				#  on link stack
+		addl %ebp,%edx			# Flatten btx_v86 ptr
+		leal 0x14(%edx),%esi		# Seg regs pointer
+		movl 0x4(%edx),%eax		# Get int no/address
+		movzwl 0x2(%edx),%edx		# Get control flags
+intusr.2:	movl %ebp,(%edi)		# Push btx_v86 and
+		movl %edi,MEM_TSS+TSS_ESP1	#  save link stack ptr
+		popl %edi			# Base of frame
+		xchgl %eax,%ebp 		# Save intno/address
+		movl 0x48(%esp,1),%eax		# Get flags
+		testb $0x2,%dl			# Simulate CALLF?
+		jnz intusr.3			# Yes
+		decl %ebx			# Push flags
+		decl %ebx			#  on V86
+		movw %ax,(%ebx) 		#  stack
+intusr.3:	movb $0x4,%cl			# Count
+		subl %ecx,%ebx			# Push return address
+		movl $inthlt,(%ebx)		#  on V86 stack
+		rep				# Copy seg regs to
+		movsl				#  exception frame
+		xchgl %eax,%ecx 		# Save flags
+		movl %ebx,%eax			# User ESP
+		subl $V86_STK,%eax		# Less bytes
+		ja intusr.4			#  to
+		xorl %eax,%eax			#  keep
+intusr.4:	shrl $0x4,%eax			# Gives segment
+		stosl				# Set SS
+		shll $0x4,%eax			# To bytes
+		xchgl %eax,%ebx 		# Swap
+		subl %ebx,%eax			# Gives offset
+		stosl				# Set ESP
+		xchgl %eax,%ecx 		# Get flags
+		btsl $0x11,%eax 		# Set VM
+		andb $~0x1,%ah			# Clear TF
+		stosl				# Set EFL
+		xchgl %eax,%ebp 		# Get int no/address
+		testb $0x1,%dl			# Address?
+		jnz intusr.5			# Yes
+		shll $0x2,%eax			# Scale
+		movl (%eax),%eax		# Load int vector
+intusr.5:	movl %eax,%ecx			# Save
+		shrl $0x10,%eax 		# Gives segment
+		stosl				# Set CS
+		movw %cx,%ax			# Restore
+		stosl				# Set EIP
+		leal 0x10(%esp,1),%esp		# Discard seg regs
+		popa				# Restore
+		iret				# To V86 mode
 /*
  * System Call.
  */
-intx30: 	cmpl $SYS_EXEC,%eax		// Exec system call?
-		jne intx30.1			// No
-		pushl %ss			// Set up
-		popl %es			//  all
-		pushl %es			//  segment
-		popl %ds			//  registers
-		pushl %ds			//  for the
-		popl %fs			//  program
-		pushl %fs			//  we're
-		popl %gs			//  invoking
-		movl $MEM_USR,%eax		// User base address
-		addl 0xc(%esp,1),%eax		// Change to user
-		leal 0x4(%eax),%esp		//  stack
+intx30: 	cmpl $SYS_EXEC,%eax		# Exec system call?
+		jne intx30.1			# No
+		pushl %ss			# Set up
+		popl %es			#  all
+		pushl %es			#  segment
+		popl %ds			#  registers
+		pushl %ds			#  for the
+		popl %fs			#  program
+		pushl %fs			#  we're
+		popl %gs			#  invoking
+		movl $MEM_USR,%eax		# User base address
+		addl 0xc(%esp,1),%eax		# Change to user
+		leal 0x4(%eax),%esp		#  stack
 #ifdef PAGING
-		movl %cr0,%eax			// Turn
-		andl $~0x80000000,%eax		//  off
-		movl %eax,%cr0			//  paging
-		xorl %eax,%eax			// Flush
-		movl %eax,%cr3			//  TLB
+		movl %cr0,%eax			# Turn
+		andl $~0x80000000,%eax		#  off
+		movl %eax,%cr0			#  paging
+		xorl %eax,%eax			# Flush
+		movl %eax,%cr3			#  TLB
 #endif
-		popl %eax			// Call
-		call *%eax			//  program
-intx30.1:	orb $0x1,%ss:btx_hdr+0x7	// Flag reboot
-		jmp exit			// Exit
+		popl %eax			# Call
+		call *%eax			#  program
+intx30.1:	orb $0x1,%ss:btx_hdr+0x7	# Flag reboot
+		jmp exit			# Exit
 /*
  * Dump structure [EBX] to [EDI], using format string [ESI].
  */
-dump.0: 	stosb				// Save char
-dump:		lodsb				// Load char
-		testb %al,%al			// End of string?
-		jz dump.10			// Yes
-		testb $0x80,%al 		// Control?
-		jz dump.0			// No
-		movb %al,%ch			// Save control
-		movb $'=',%al			// Append
-		stosb				//  '='
-		lodsb				// Get offset
-		pushl %esi			// Save
-		movsbl %al,%esi 		// To
-		addl %ebx,%esi			//  pointer
-		testb $DMP_X16,%ch		// Dump word?
-		jz dump.1			// No
-		lodsw				// Get and
-		call hex16			//  dump it
-dump.1: 	testb $DMP_X32,%ch		// Dump long?
-		jz dump.2			// No
-		lodsl				// Get and
-		call hex32			//  dump it
-dump.2: 	testb $DMP_MEM,%ch		// Dump memory?
-		jz dump.8			// No
-		pushl %ds			// Save
-		testb $0x2,0x52(%ebx)		// V86 mode?
-		jnz dump.3			// Yes
-		verr 0x4(%esi)	 		// Readable selector?
-		jnz dump.3			// No
-		ldsl (%esi),%esi		// Load pointer
-		jmp dump.4			// Join common code
-dump.3: 	lodsl				// Set offset
-		xchgl %eax,%edx 		// Save
-		lodsl				// Get segment
-		shll $0x4,%eax			//  * 0x10
-		addl %edx,%eax			//  + offset
-		xchgl %eax,%esi 		// Set pointer
-dump.4: 	movb $2,%dl			// Num lines
-dump.4a:	movb $0x10,%cl			// Bytes to dump
-dump.5: 	lodsb				// Get byte and
-		call hex8			//  dump it
-		decb %cl			// Keep count
-		jz dump.6a			// If done
-		movb $'-',%al			// Separator
-		cmpb $0x8,%cl			// Half way?
-		je dump.6			// Yes
-		movb $' ',%al			// Use space
-dump.6: 	stosb				// Save separator
-		jmp dump.5			// Continue
-dump.6a:	decb %dl			// Keep count
-		jz dump.7			// If done
-		movb $0xa,%al			// Line feed
-		stosb				// Save one
-		movb $7,%cl			// Leading
-		movb $' ',%al			//  spaces
-dump.6b:	stosb				// Dump
-		decb %cl			//  spaces
+dump.0: 	stosb				# Save char
+dump:		lodsb				# Load char
+		testb %al,%al			# End of string?
+		jz dump.10			# Yes
+		testb $0x80,%al 		# Control?
+		jz dump.0			# No
+		movb %al,%ch			# Save control
+		movb $'=',%al			# Append
+		stosb				#  '='
+		lodsb				# Get offset
+		pushl %esi			# Save
+		movsbl %al,%esi 		# To
+		addl %ebx,%esi			#  pointer
+		testb $DMP_X16,%ch		# Dump word?
+		jz dump.1			# No
+		lodsw				# Get and
+		call hex16			#  dump it
+dump.1: 	testb $DMP_X32,%ch		# Dump long?
+		jz dump.2			# No
+		lodsl				# Get and
+		call hex32			#  dump it
+dump.2: 	testb $DMP_MEM,%ch		# Dump memory?
+		jz dump.8			# No
+		pushl %ds			# Save
+		testb $0x2,0x52(%ebx)		# V86 mode?
+		jnz dump.3			# Yes
+		verr 0x4(%esi)	 		# Readable selector?
+		jnz dump.3			# No
+		ldsl (%esi),%esi		# Load pointer
+		jmp dump.4			# Join common code
+dump.3: 	lodsl				# Set offset
+		xchgl %eax,%edx 		# Save
+		lodsl				# Get segment
+		shll $0x4,%eax			#  * 0x10
+		addl %edx,%eax			#  + offset
+		xchgl %eax,%esi 		# Set pointer
+dump.4: 	movb $2,%dl			# Num lines
+dump.4a:	movb $0x10,%cl			# Bytes to dump
+dump.5: 	lodsb				# Get byte and
+		call hex8			#  dump it
+		decb %cl			# Keep count
+		jz dump.6a			# If done
+		movb $'-',%al			# Separator
+		cmpb $0x8,%cl			# Half way?
+		je dump.6			# Yes
+		movb $' ',%al			# Use space
+dump.6: 	stosb				# Save separator
+		jmp dump.5			# Continue
+dump.6a:	decb %dl			# Keep count
+		jz dump.7			# If done
+		movb $0xa,%al			# Line feed
+		stosb				# Save one
+		movb $7,%cl			# Leading
+		movb $' ',%al			#  spaces
+dump.6b:	stosb				# Dump
+		decb %cl			#  spaces
 		jnz dump.6b
-		jmp dump.4a			// Next line
-dump.7: 	popl %ds			// Restore
-dump.8: 	popl %esi			// Restore
-		movb $0xa,%al			// Line feed
-		testb $DMP_EOL,%ch		// End of line?
-		jnz dump.9			// Yes
-		movb $' ',%al			// Use spaces
-		stosb				// Save one
-dump.9: 	jmp dump.0			// Continue
-dump.10:	stosb				// Terminate string
-		ret				// To caller
+		jmp dump.4a			# Next line
+dump.7: 	popl %ds			# Restore
+dump.8: 	popl %esi			# Restore
+		movb $0xa,%al			# Line feed
+		testb $DMP_EOL,%ch		# End of line?
+		jnz dump.9			# Yes
+		movb $' ',%al			# Use spaces
+		stosb				# Save one
+dump.9: 	jmp dump.0			# Continue
+dump.10:	stosb				# Terminate string
+		ret				# To caller
 /*
  * Convert EAX, AX, or AL to hex, saving the result to [EDI].
  */
-hex32:		pushl %eax			// Save
-		shrl $0x10,%eax 		// Do upper
-		call hex16			//  16
-		popl %eax			// Restore
-hex16:		call hex16.1			// Do upper 8
-hex16.1:	xchgb %ah,%al			// Save/restore
-hex8:		pushl %eax			// Save
-		shrb $0x4,%al			// Do upper
-		call hex8.1			//  4
-		popl %eax			// Restore
-hex8.1: 	andb $0xf,%al			// Get lower 4
-		cmpb $0xa,%al			// Convert
-		sbbb $0x69,%al			//  to hex
-		das				//  digit
-		orb $0x20,%al			// To lower case
-		stosb				// Save char
-		ret				// (Recursive)
+hex32:		pushl %eax			# Save
+		shrl $0x10,%eax 		# Do upper
+		call hex16			#  16
+		popl %eax			# Restore
+hex16:		call hex16.1			# Do upper 8
+hex16.1:	xchgb %ah,%al			# Save/restore
+hex8:		pushl %eax			# Save
+		shrb $0x4,%al			# Do upper
+		call hex8.1			#  4
+		popl %eax			# Restore
+hex8.1: 	andb $0xf,%al			# Get lower 4
+		cmpb $0xa,%al			# Convert
+		sbbb $0x69,%al			#  to hex
+		das				#  digit
+		orb $0x20,%al			# To lower case
+		stosb				# Save char
+		ret				# (Recursive)
 /*
  * Output zero-terminated string [ESI] to the console.
  */
-putstr.0:	call putchr			// Output char
-putstr: 	lodsb				// Load char
-		testb %al,%al			// End of string?
-		jnz putstr.0			// No
-		ret				// To caller
+putstr.0:	call putchr			# Output char
+putstr: 	lodsb				# Load char
+		testb %al,%al			# End of string?
+		jnz putstr.0			# No
+		ret				# To caller
 #ifdef BTX_SERIAL
-		.set SIO_PRT,SIOPRT		// Base port
-		.set SIO_FMT,SIOFMT		// 8N1
-		.set SIO_DIV,(115200/SIOSPD)	// 115200 / SPD
+		.set SIO_PRT,SIOPRT		# Base port
+		.set SIO_FMT,SIOFMT		# 8N1
+		.set SIO_DIV,(115200/SIOSPD)	# 115200 / SPD
 
  * void sio_init(void)
 
-sio_init:	movw $SIO_PRT+0x3,%dx		// Data format reg
-		movb $SIO_FMT|0x80,%al		// Set format
-		outb %al,(%dx)			//  and DLAB
-		pushl %edx			// Save
-		subb $0x3,%dl			// Divisor latch reg
-		movw $SIO_DIV,%ax		// Set
-		outw %ax,(%dx)			//  BPS
-		popl %edx			// Restore
-		movb $SIO_FMT,%al		// Clear
-		outb %al,(%dx)			//  DLAB
-		incl %edx			// Modem control reg
-		movb $0x3,%al			// Set RTS,
-		outb %al,(%dx)			//  DTR
-		incl %edx			// Line status reg
+sio_init:	movw $SIO_PRT+0x3,%dx		# Data format reg
+		movb $SIO_FMT|0x80,%al		# Set format
+		outb %al,(%dx)			#  and DLAB
+		pushl %edx			# Save
+		subb $0x3,%dl			# Divisor latch reg
+		movw $SIO_DIV,%ax		# Set
+		outw %ax,(%dx)			#  BPS
+		popl %edx			# Restore
+		movb $SIO_FMT,%al		# Clear
+		outb %al,(%dx)			#  DLAB
+		incl %edx			# Modem control reg
+		movb $0x3,%al			# Set RTS,
+		outb %al,(%dx)			#  DTR
+		incl %edx			# Line status reg
 
  * void sio_flush(void)
 
-sio_flush.0:	call sio_getc.1 		// Get character
-sio_flush:	call sio_ischar 		// Check for character
-		jnz sio_flush.0 		// Till none
-		ret				// To caller
+sio_flush.0:	call sio_getc.1 		# Get character
+sio_flush:	call sio_ischar 		# Check for character
+		jnz sio_flush.0 		# Till none
+		ret				# To caller
 
  * void sio_putc(int c)
 
-sio_putc:	movw $SIO_PRT+0x5,%dx		// Line status reg
-		xor %ecx,%ecx			// Timeout
-		movb $0x40,%ch			//  counter
-sio_putc.1:	inb (%dx),%al			// Transmitter
-		testb $0x20,%al 		//  buffer empty?
-		loopz sio_putc.1		// No
-		jz sio_putc.2			// If timeout
-		movb 0x4(%esp,1),%al		// Get character
-		subb $0x5,%dl			// Transmitter hold reg
-		outb %al,(%dx)			// Write character
-sio_putc.2:	ret $0x4			// To caller
+sio_putc:	movw $SIO_PRT+0x5,%dx		# Line status reg
+		xor %ecx,%ecx			# Timeout
+		movb $0x40,%ch			#  counter
+sio_putc.1:	inb (%dx),%al			# Transmitter
+		testb $0x20,%al 		#  buffer empty?
+		loopz sio_putc.1		# No
+		jz sio_putc.2			# If timeout
+		movb 0x4(%esp,1),%al		# Get character
+		subb $0x5,%dl			# Transmitter hold reg
+		outb %al,(%dx)			# Write character
+sio_putc.2:	ret $0x4			# To caller
 
  * int sio_getc(void)
 
-sio_getc:	call sio_ischar 		// Character available?
-		jz sio_getc			// No
-sio_getc.1:	subb $0x5,%dl			// Receiver buffer reg
-		inb (%dx),%al			// Read character
-		ret				// To caller
+sio_getc:	call sio_ischar 		# Character available?
+		jz sio_getc			# No
+sio_getc.1:	subb $0x5,%dl			# Receiver buffer reg
+		inb (%dx),%al			# Read character
+		ret				# To caller
 
  * int sio_ischar(void)
 
-sio_ischar:	movw $SIO_PRT+0x5,%dx		// Line status register
-		xorl %eax,%eax			// Zero
-		inb (%dx),%al			// Received data
-		andb $0x1,%al			//  ready?
-		ret				// To caller
+sio_ischar:	movw $SIO_PRT+0x5,%dx		# Line status register
+		xorl %eax,%eax			# Zero
+		inb (%dx),%al			# Received data
+		andb $0x1,%al			#  ready?
+		ret				# To caller
 
 /*
  * Output character AL to the serial console.
  */
-putchr: 	pusha				// Save
-		cmpb $10, %al			// is it a newline?
-		jne putchr.1			//  no?, then leave
-		push $13			// output a carriage
-		call sio_putc			//  return first
-		movb $10, %al			// restore %al
-putchr.1:	pushl %eax			// Push the character
-						//  onto the stack
-		call sio_putc			// Output the character
-		popa				// Restore
-		ret				// To caller
+putchr: 	pusha				# Save
+		cmpb $10, %al			# is it a newline?
+		jne putchr.1			#  no?, then leave
+		push $13			# output a carriage
+		call sio_putc			#  return first
+		movb $10, %al			# restore %al
+putchr.1:	pushl %eax			# Push the character
+						#  onto the stack
+		call sio_putc			# Output the character
+		popa				# Restore
+		ret				# To caller
 #else
 /*
  * Output character AL to the console.
  */
-putchr: 	pusha				// Save
-		xorl %ecx,%ecx			// Zero for loops
-		movb $SCR_MAT,%ah		// Mode/attribute
-		movl $BDA_POS,%ebx		// BDA pointer
-		movw (%ebx),%dx 		// Cursor position
-		movl $0xb8000,%edi		// Regen buffer (color)
-		cmpb %ah,BDA_SCR-BDA_POS(%ebx)	// Mono mode?
-		jne putchr.1			// No
-		xorw %di,%di			// Regen buffer (mono)
-putchr.1:	cmpb $0xa,%al			// New line?
-		je putchr.2			// Yes
-		xchgl %eax,%ecx 		// Save char
-		movb $SCR_COL,%al		// Columns per row
-		mulb %dh			//  * row position
-		addb %dl,%al			//  + column
-		adcb $0x0,%ah			//  position
-		shll %eax			//  * 2
-		xchgl %eax,%ecx 		// Swap char, offset
-		movw %ax,(%edi,%ecx,1)		// Write attr:char
-		incl %edx			// Bump cursor
-		cmpb $SCR_COL,%dl		// Beyond row?
-		jb putchr.3			// No
-putchr.2:	xorb %dl,%dl			// Zero column
-		incb %dh			// Bump row
-putchr.3:	cmpb $SCR_ROW,%dh		// Beyond screen?
-		jb putchr.4			// No
-		leal 2*SCR_COL(%edi),%esi	// New top line
-		movw $(SCR_ROW-1)*SCR_COL/2,%cx // Words to move
-		rep				// Scroll
-		movsl				//  screen
-		movb $0x20,%al			// Space
-		movb $SCR_COL,%cl		// Columns to clear
-		rep				// Clear
-		stosw				//  line
-		movb $SCR_ROW-1,%dh		// Bottom line
-putchr.4:	movw %dx,(%ebx) 		// Update position
-		popa				// Restore
-		ret				// To caller
+putchr: 	pusha				# Save
+		xorl %ecx,%ecx			# Zero for loops
+		movb $SCR_MAT,%ah		# Mode/attribute
+		movl $BDA_POS,%ebx		# BDA pointer
+		movw (%ebx),%dx 		# Cursor position
+		movl $0xb8000,%edi		# Regen buffer (color)
+		cmpb %ah,BDA_SCR-BDA_POS(%ebx)	# Mono mode?
+		jne putchr.1			# No
+		xorw %di,%di			# Regen buffer (mono)
+putchr.1:	cmpb $0xa,%al			# New line?
+		je putchr.2			# Yes
+		xchgl %eax,%ecx 		# Save char
+		movb $SCR_COL,%al		# Columns per row
+		mulb %dh			#  * row position
+		addb %dl,%al			#  + column
+		adcb $0x0,%ah			#  position
+		shll %eax			#  * 2
+		xchgl %eax,%ecx 		# Swap char, offset
+		movw %ax,(%edi,%ecx,1)		# Write attr:char
+		incl %edx			# Bump cursor
+		cmpb $SCR_COL,%dl		# Beyond row?
+		jb putchr.3			# No
+putchr.2:	xorb %dl,%dl			# Zero column
+		incb %dh			# Bump row
+putchr.3:	cmpb $SCR_ROW,%dh		# Beyond screen?
+		jb putchr.4			# No
+		leal 2*SCR_COL(%edi),%esi	# New top line
+		movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move
+		rep				# Scroll
+		movsl				#  screen
+		movb $0x20,%al			# Space
+		movb $SCR_COL,%cl		# Columns to clear
+		rep				# Clear
+		stosw				#  line
+		movb $SCR_ROW-1,%dh		# Bottom line
+putchr.4:	movw %dx,(%ebx) 		# Update position
+		popa				# Restore
+		ret				# To caller
 #endif
 
 		.p2align 4
 /*
  * Global descriptor table.
  */
-gdt:		.word 0x0,0x0,0x0,0x0		// Null entry
-		.word 0xffff,0x0,0x9a00,0xcf	// SEL_SCODE
-		.word 0xffff,0x0,0x9200,0xcf	// SEL_SDATA
-		.word 0xffff,0x0,0x9a00,0x0	// SEL_RCODE
-		.word 0xffff,0x0,0x9200,0x0	// SEL_RDATA
-		.word 0xffff,MEM_USR,0xfa00,0xcf// SEL_UCODE
-		.word 0xffff,MEM_USR,0xf200,0xcf// SEL_UDATA
-		.word _TSSLM,MEM_TSS,0x8900,0x0 // SEL_TSS
+gdt:		.word 0x0,0x0,0x0,0x0		# Null entry
+		.word 0xffff,0x0,0x9a00,0xcf	# SEL_SCODE
+		.word 0xffff,0x0,0x9200,0xcf	# SEL_SDATA
+		.word 0xffff,0x0,0x9a00,0x0	# SEL_RCODE
+		.word 0xffff,0x0,0x9200,0x0	# SEL_RDATA
+		.word 0xffff,MEM_USR,0xfa00,0xcf# SEL_UCODE
+		.word 0xffff,MEM_USR,0xf200,0xcf# SEL_UDATA
+		.word _TSSLM,MEM_TSS,0x8900,0x0 # SEL_TSS
 gdt.1:
 /*
  * Pseudo-descriptors.
  */
-gdtdesc:	.word gdt.1-gdt-1,gdt,0x0	// GDT
-idtdesc:	.word _IDTLM,MEM_IDT,0x0	// IDT
-ivtdesc:	.word 0x400-0x0-1,0x0,0x0	// IVT
+gdtdesc:	.word gdt.1-gdt-1,gdt,0x0	# GDT
+idtdesc:	.word _IDTLM,MEM_IDT,0x0	# IDT
+ivtdesc:	.word 0x400-0x0-1,0x0,0x0	# IVT
 /*
  * IDT construction control string.
  */
-idtctl: 	.byte 0x10,  0x8e		// Int 0x0-0xf
-		.word 0x7dfb,intx00		//  (exceptions)
-		.byte 0x10,  0x8e		// Int 0x10
-		.word 0x1,   intx10		//  (exception)
-		.byte 0x10,  0x8e		// Int 0x20-0x2f
-		.word 0xffff,intx20		//  (hardware)
-		.byte 0x1,   0xee		// int 0x30
-		.word 0x1,   intx30		//  (system call)
-		.byte 0x2,   0xee		// Int 0x31-0x32
-		.word 0x1,   intx31		//  (V86, null)
-		.byte 0x0			// End of string
+idtctl: 	.byte 0x10,  0x8e		# Int 0x0-0xf
+		.word 0x7dfb,intx00		#  (exceptions)
+		.byte 0x10,  0x8e		# Int 0x10
+		.word 0x1,   intx10		#  (exception)
+		.byte 0x10,  0x8e		# Int 0x20-0x2f
+		.word 0xffff,intx20		#  (hardware)
+		.byte 0x1,   0xee		# int 0x30
+		.word 0x1,   intx30		#  (system call)
+		.byte 0x2,   0xee		# Int 0x31-0x32
+		.word 0x1,   intx31		#  (V86, null)
+		.byte 0x0			# End of string
 /*
  * Dump format string.
  */
-dmpfmt: 	.byte '\n'			// "\n"
-		.ascii "int"			// "int="
-		.byte 0x80|DMP_X32,	   0x40 // "00000000  "
-		.ascii "err"			// "err="
-		.byte 0x80|DMP_X32,	   0x44 // "00000000  "
-		.ascii "efl"			// "efl="
-		.byte 0x80|DMP_X32,	   0x50 // "00000000  "
-		.ascii "eip"			// "eip="
-		.byte 0x80|DMP_X32|DMP_EOL,0x48 // "00000000\n"
-		.ascii "eax"			// "eax="
-		.byte 0x80|DMP_X32,	   0x34 // "00000000  "
-		.ascii "ebx"			// "ebx="
-		.byte 0x80|DMP_X32,	   0x28 // "00000000  "
-		.ascii "ecx"			// "ecx="
-		.byte 0x80|DMP_X32,	   0x30 // "00000000  "
-		.ascii "edx"			// "edx="
-		.byte 0x80|DMP_X32|DMP_EOL,0x2c // "00000000\n"
-		.ascii "esi"			// "esi="
-		.byte 0x80|DMP_X32,	   0x1c // "00000000  "
-		.ascii "edi"			// "edi="
-		.byte 0x80|DMP_X32,	   0x18 // "00000000  "
-		.ascii "ebp"			// "ebp="
-		.byte 0x80|DMP_X32,	   0x20 // "00000000  "
-		.ascii "esp"			// "esp="
-		.byte 0x80|DMP_X32|DMP_EOL,0x0	// "00000000\n"
-		.ascii "cs"			// "cs="
-		.byte 0x80|DMP_X16,	   0x4c // "0000  "
-		.ascii "ds"			// "ds="
-		.byte 0x80|DMP_X16,	   0xc	// "0000  "
-		.ascii "es"			// "es="
-		.byte 0x80|DMP_X16,	   0x8	// "0000  "
-		.ascii "  "			// "  "
-		.ascii "fs"			// "fs="
-		.byte 0x80|DMP_X16,	   0x10 // "0000  "
-		.ascii "gs"			// "gs="
-		.byte 0x80|DMP_X16,	   0x14 // "0000  "
-		.ascii "ss"			// "ss="
-		.byte 0x80|DMP_X16|DMP_EOL,0x4	// "0000\n"
-		.ascii "cs:eip" 		// "cs:eip="
-		.byte 0x80|DMP_MEM|DMP_EOL,0x48 // "00 00 ... 00 00\n"
-		.ascii "ss:esp" 		// "ss:esp="
-		.byte 0x80|DMP_MEM|DMP_EOL,0x0	// "00 00 ... 00 00\n"
-		.asciz "BTX halted\n"		// End
+dmpfmt: 	.byte '\n'			# "\n"
+		.ascii "int"			# "int="
+		.byte 0x80|DMP_X32,	   0x40 # "00000000  "
+		.ascii "err"			# "err="
+		.byte 0x80|DMP_X32,	   0x44 # "00000000  "
+		.ascii "efl"			# "efl="
+		.byte 0x80|DMP_X32,	   0x50 # "00000000  "
+		.ascii "eip"			# "eip="
+		.byte 0x80|DMP_X32|DMP_EOL,0x48 # "00000000\n"
+		.ascii "eax"			# "eax="
+		.byte 0x80|DMP_X32,	   0x34 # "00000000  "
+		.ascii "ebx"			# "ebx="
+		.byte 0x80|DMP_X32,	   0x28 # "00000000  "
+		.ascii "ecx"			# "ecx="
+		.byte 0x80|DMP_X32,	   0x30 # "00000000  "
+		.ascii "edx"			# "edx="
+		.byte 0x80|DMP_X32|DMP_EOL,0x2c # "00000000\n"
+		.ascii "esi"			# "esi="
+		.byte 0x80|DMP_X32,	   0x1c # "00000000  "
+		.ascii "edi"			# "edi="
+		.byte 0x80|DMP_X32,	   0x18 # "00000000  "
+		.ascii "ebp"			# "ebp="
+		.byte 0x80|DMP_X32,	   0x20 # "00000000  "
+		.ascii "esp"			# "esp="
+		.byte 0x80|DMP_X32|DMP_EOL,0x0	# "00000000\n"
+		.ascii "cs"			# "cs="
+		.byte 0x80|DMP_X16,	   0x4c # "0000  "
+		.ascii "ds"			# "ds="
+		.byte 0x80|DMP_X16,	   0xc	# "0000  "
+		.ascii "es"			# "es="
+		.byte 0x80|DMP_X16,	   0x8	# "0000  "
+		.ascii "  "			# "  "
+		.ascii "fs"			# "fs="
+		.byte 0x80|DMP_X16,	   0x10 # "0000  "
+		.ascii "gs"			# "gs="
+		.byte 0x80|DMP_X16,	   0x14 # "0000  "
+		.ascii "ss"			# "ss="
+		.byte 0x80|DMP_X16|DMP_EOL,0x4	# "0000\n"
+		.ascii "cs:eip" 		# "cs:eip="
+		.byte 0x80|DMP_MEM|DMP_EOL,0x48 # "00 00 ... 00 00\n"
+		.ascii "ss:esp" 		# "ss:esp="
+		.byte 0x80|DMP_MEM|DMP_EOL,0x0	# "00 00 ... 00 00\n"
+		.asciz "BTX halted\n"		# End
 /*
  * End of BTX memory.
  */