Back out last revision that unnecessarily changed valid assembler

line comments and damaged the CVS history.

Prompted by:	bde, jhb

1 files changed, 163 insertions, 167 deletions

diff --git a/sys/boot/i386/pxeldr/pxeldr.S b/sys/boot/i386/pxeldr/pxeldr.S
index 7c09c8a..25ab5c0 100644
--- a/sys/boot/i386/pxeldr/pxeldr.S
+++ b/sys/boot/i386/pxeldr/pxeldr.S
@@ -19,7 +19,7 @@
  * This simple program is a preloader for the normal boot3 loader.  It is simply
  * prepended to the beginning of a fully built and btxld'd loader.  It then
  * copies the loader to the address boot2 normally loads it, emulates the
- * boot[12] environment (protected mode, a bootinfo struct, etc.) and then jumps
+ * boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps
  * to the start of btxldr to start the boot process.  This method allows a stock
  * /boot/loader to be booted over the network via PXE w/o having to write a
  * separate PXE-aware client just to load the loader.
@@ -28,45 +28,45 @@
 /*
  * Memory locations.
  */
-		.set MEM_PAGE_SIZE,0x1000	// memory page size, 4k
-		.set MEM_ARG,0x900		// Arguments at start
-		.set MEM_ARG_BTX,0xa100		// Where we move them to so the
-						//  BTX client can see them
-		.set MEM_ARG_SIZE,0x18		// Size of the arguments
-		.set MEM_BTX_ADDRESS,0x9000	// where BTX lives
-		.set MEM_BTX_ENTRY,0x9010	// where BTX starts to execute
-		.set MEM_BTX_OFFSET,MEM_PAGE_SIZE // offset of BTX in the loader
-		.set MEM_BTX_CLIENT,0xa000	// where BTX clients live
-		.set MEM_BIOS_KEYBOARD,0x496	// BDA byte with keyboard bit
+		.set MEM_PAGE_SIZE,0x1000	# memory page size, 4k
+		.set MEM_ARG,0x900		# Arguments at start
+		.set MEM_ARG_BTX,0xa100		# Where we move them to so the
+						#  BTX client can see them
+		.set MEM_ARG_SIZE,0x18		# Size of the arguments
+		.set MEM_BTX_ADDRESS,0x9000	# where BTX lives
+		.set MEM_BTX_ENTRY,0x9010	# where BTX starts to execute
+		.set MEM_BTX_OFFSET,MEM_PAGE_SIZE # offset of BTX in the loader
+		.set MEM_BTX_CLIENT,0xa000	# where BTX clients live
+		.set MEM_BIOS_KEYBOARD,0x496	# BDA byte with keyboard bit
 /*
  * a.out header fields
  */
-		.set AOUT_TEXT,0x04		// text segment size
-		.set AOUT_DATA,0x08		// data segment size
-		.set AOUT_BSS,0x0c		// zero'd BSS size
-		.set AOUT_SYMBOLS,0x10		// symbol table
-		.set AOUT_ENTRY,0x14		// entry point
-		.set AOUT_HEADER,MEM_PAGE_SIZE	// size of the a.out header
+		.set AOUT_TEXT,0x04		# text segment size
+		.set AOUT_DATA,0x08		# data segment size
+		.set AOUT_BSS,0x0c		# zero'd BSS size
+		.set AOUT_SYMBOLS,0x10		# symbol table
+		.set AOUT_ENTRY,0x14		# entry point
+		.set AOUT_HEADER,MEM_PAGE_SIZE	# size of the a.out header
 /*
  * Flags for kargs->bootflags
  */
-		.set KARGS_FLAGS_PXE,0x2	// flag to indicate booting from
-						//  PXE loader
+		.set KARGS_FLAGS_PXE,0x2	# flag to indicate booting from
+						#  PXE loader
 /*
  * Boot howto bits
  */
-		.set RB_SERIAL,0x1000		// serial console
+		.set RB_SERIAL,0x1000		# serial console
 /*
  * Segment selectors.
  */
-		.set SEL_SDATA,0x8		// Supervisor data
-		.set SEL_RDATA,0x10		// Real mode data
-		.set SEL_SCODE,0x18		// PM-32 code
-		.set SEL_SCODE16,0x20		// PM-16 code
+		.set SEL_SDATA,0x8		# Supervisor data
+		.set SEL_RDATA,0x10		# Real mode data
+		.set SEL_SCODE,0x18		# PM-32 code
+		.set SEL_SCODE16,0x20		# PM-16 code
 /*
  * BTX constants
  */
-		.set INT_SYS,0x30		// BTX syscall interrupt
+		.set INT_SYS,0x30		# BTX syscall interrupt
 /*
  * Bit in MEM_BIOS_KEYBOARD that is set if an enhanced keyboard is present
  */
@@ -81,190 +81,186 @@
 /*
  * BTX program loader for PXE network booting
  */
-start:		cld				// string ops inc
-		xorw %ax, %ax			// zero %ax
-		movw %ax, %ss			// setup the
-		movw $start, %sp		//  stack
-		movw %es, %cx			// save PXENV+ segment
-		movw %ax, %ds			// setup the
-		movw %ax, %es			//  data segments
-		andl $0xffff, %ecx		// clear upper words
-		andl $0xffff, %ebx		//  of %ebx and %ecx
-		shll $4, %ecx			// calculate the offset of
-		addl %ebx, %ecx			//  the PXENV+ struct and
-		pushl %ecx			//  save it on the stack
-		movw $welcome_msg, %si		// %ds:(%si) -> welcome message
-		callw putstr			// display the welcome message
+start:		cld				# string ops inc
+		xorw %ax, %ax			# zero %ax
+		movw %ax, %ss			# setup the
+		movw $start, %sp		#  stack
+		movw %es, %cx			# save PXENV+ segment
+		movw %ax, %ds			# setup the
+		movw %ax, %es			#  data segments
+		andl $0xffff, %ecx		# clear upper words
+		andl $0xffff, %ebx		#  of %ebx and %ecx
+		shll $4, %ecx			# calculate the offset of
+		addl %ebx, %ecx			#  the PXENV+ struct and
+		pushl %ecx			#  save it on the stack
+		movw $welcome_msg, %si		# %ds:(%si) -> welcome message
+		callw putstr			# display the welcome message
 /*
  * Setup the arguments that the loader is expecting from boot[12]
  */
-		movw $bootinfo_msg, %si		// %ds:(%si) -> boot args
-						//  message
-		callw putstr			// display the message
-		movw $MEM_ARG, %bx		// %ds:(%bx) -> boot args
-		movw %bx, %di			// %es:(%di) -> boot args
-		xorl %eax, %eax			// zero %eax
-		movw $(MEM_ARG_SIZE/4), %cx	// Size of arguments in 32-bit
-						//  dwords
-		rep				// Clear the arguments
-		stosl				//  to zero
-		orb $KARGS_FLAGS_PXE, 0x8(%bx)	// kargs->bootflags |=
-						//  KARGS_FLAGS_PXE
-		popl 0xc(%bx)			// kargs->pxeinfo = *PXENV+
+		movw $bootinfo_msg, %si		# %ds:(%si) -> boot args message
+		callw putstr			# display the message
+		movw $MEM_ARG, %bx		# %ds:(%bx) -> boot args
+		movw %bx, %di			# %es:(%di) -> boot args
+		xorl %eax, %eax			# zero %eax
+		movw $(MEM_ARG_SIZE/4), %cx	# Size of arguments in 32-bit
+						#  dwords
+		rep				# Clear the arguments
+		stosl				#  to zero
+		orb $KARGS_FLAGS_PXE, 0x8(%bx)	# kargs->bootflags |=
+						#  KARGS_FLAGS_PXE
+		popl 0xc(%bx)			# kargs->pxeinfo = *PXENV+
 #ifdef ALWAYS_SERIAL
 /*
  * set the RBX_SERIAL bit in the howto byte.
  */
-		orl $RB_SERIAL, (%bx)		// enable serial console
+		orl $RB_SERIAL, (%bx)		# enable serial console
 #endif
 #ifdef PROBE_KEYBOARD
 /*
  * Look at the BIOS data area to see if we have an enhanced keyboard.  If not,
  * set the RBX_SERIAL bit in the howto byte.
  */
-		testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD // keyboard present?
-		jnz keyb			// yes, so skip
-		orl $RB_SERIAL, (%bx)		// enable serial console
+		testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD # keyboard present?
+		jnz keyb			# yes, so skip
+		orl $RB_SERIAL, (%bx)		# enable serial console
 keyb:
 #endif
 /*
  * Turn on the A20 address line
  */
-		callw seta20			// Turn A20 on
+		callw seta20			# Turn A20 on
 /*
  * Relocate the loader and BTX using a very lazy protected mode
  */
-		movw $relocate_msg, %si		// Display the
-		callw putstr			//  relocation message
-		movl end+AOUT_ENTRY, %edi	// %edi is the destination
-		movl $(end+AOUT_HEADER), %esi	// %esi is
-						//  the start of the text
-						//  segment
-		movl end+AOUT_TEXT, %ecx	// %ecx = length of the text
-						//  segment
-		lgdt gdtdesc			// setup our own gdt
-		cli				// turn off interrupts
-		movl %cr0, %eax			// Turn on
-		orb $0x1, %al			//  protected
-		movl %eax, %cr0			//  mode
-		ljmp $SEL_SCODE,$pm_start	// long jump to clear the
-						//  instruction pre-fetch queue
+		movw $relocate_msg, %si		# Display the
+		callw putstr			#  relocation message
+		movl end+AOUT_ENTRY, %edi	# %edi is the destination
+		movl $(end+AOUT_HEADER), %esi	# %esi is
+						#  the start of the text
+						#  segment
+		movl end+AOUT_TEXT, %ecx	# %ecx = length of the text
+						#  segment
+		lgdt gdtdesc			# setup our own gdt
+		cli				# turn off interrupts
+		movl %cr0, %eax			# Turn on
+		orb $0x1, %al			#  protected
+		movl %eax, %cr0			#  mode
+		ljmp $SEL_SCODE,$pm_start	# long jump to clear the
+						#  instruction pre-fetch queue
 		.code32
-pm_start:	movw $SEL_SDATA, %ax		// Initialize
-		movw %ax, %ds			//  %ds and
-		movw %ax, %es			//  %es to a flat selector
-		rep				// Relocate the
-		movsb				//  text segment
-		addl $(MEM_PAGE_SIZE - 1), %edi	// pad %edi out to a new page
-		andl $~(MEM_PAGE_SIZE - 1), %edi //  for the data segment
-		movl end+AOUT_DATA, %ecx	// size of the data segment
-		rep				// Relocate the
-		movsb				//  data segment
-		movl end+AOUT_BSS, %ecx		// size of the bss
-		xorl %eax, %eax			// zero %eax
-		addb $3, %cl			// round %ecx up to
-		shrl $2, %ecx			//  a multiple of 4
-		rep				// zero the
-		stosl				//  bss
-		movl end+AOUT_ENTRY, %esi	// %esi -> relocated loader
-		addl $MEM_BTX_OFFSET, %esi	// %esi -> BTX in the loader
-		movl $MEM_BTX_ADDRESS, %edi	// %edi -> where BTX needs to go
-		movzwl 0xa(%esi), %ecx		// %ecx -> length of BTX
-		rep				// Relocate
-		movsb				//  BTX
-		ljmp $SEL_SCODE16,$pm_16	// Jump to 16-bit PM
+pm_start:	movw $SEL_SDATA, %ax		# Initialize
+		movw %ax, %ds			#  %ds and
+		movw %ax, %es			#  %es to a flat selector
+		rep				# Relocate the
+		movsb				#  text segment
+		addl $(MEM_PAGE_SIZE - 1), %edi	# pad %edi out to a new page
+		andl $~(MEM_PAGE_SIZE - 1), %edi #  for the data segment
+		movl end+AOUT_DATA, %ecx	# size of the data segment
+		rep				# Relocate the
+		movsb				#  data segment
+		movl end+AOUT_BSS, %ecx		# size of the bss
+		xorl %eax, %eax			# zero %eax
+		addb $3, %cl			# round %ecx up to
+		shrl $2, %ecx			#  a multiple of 4
+		rep				# zero the
+		stosl				#  bss
+		movl end+AOUT_ENTRY, %esi	# %esi -> relocated loader
+		addl $MEM_BTX_OFFSET, %esi	# %esi -> BTX in the loader
+		movl $MEM_BTX_ADDRESS, %edi	# %edi -> where BTX needs to go
+		movzwl 0xa(%esi), %ecx		# %ecx -> length of BTX
+		rep				# Relocate
+		movsb				#  BTX
+		ljmp $SEL_SCODE16,$pm_16	# Jump to 16-bit PM
 		.code16
-pm_16:		movw $SEL_RDATA, %ax		// Initialize
-		movw %ax, %ds			//  %ds and
-		movw %ax, %es			//  %es to a real mode selector
-		movl %cr0, %eax			// Turn off
-		andb $~0x1, %al			//  protected
-		movl %eax, %cr0			//  mode
-		ljmp $0,$pm_end			// Long jump to clear the
-						//  instruction pre-fetch queue
-pm_end:		sti				// Turn interrupts back on now
+pm_16:		movw $SEL_RDATA, %ax		# Initialize
+		movw %ax, %ds			#  %ds and
+		movw %ax, %es			#  %es to a real mode selector
+		movl %cr0, %eax			# Turn off
+		andb $~0x1, %al			#  protected
+		movl %eax, %cr0			#  mode
+		ljmp $0,$pm_end			# Long jump to clear the
+						#  instruction pre-fetch queue
+pm_end:		sti				# Turn interrupts back on now
 /*
  * Copy the BTX client to MEM_BTX_CLIENT
  */
-		xorw %ax, %ax			// zero %ax and set
-		movw %ax, %ds			//  %ds and %es
-		movw %ax, %es			//  to segment 0
-		movw $MEM_BTX_CLIENT, %di	// Prepare to relocate
-		movw $btx_client, %si		//  the simple btx client
-		movw $(btx_client_end-btx_client), %cx // length of btx client
-		rep				// Relocate the
-		movsb				//  simple BTX client
+		xorw %ax, %ax			# zero %ax and set
+		movw %ax, %ds			#  %ds and %es
+		movw %ax, %es			#  to segment 0
+		movw $MEM_BTX_CLIENT, %di	# Prepare to relocate
+		movw $btx_client, %si		#  the simple btx client
+		movw $(btx_client_end-btx_client), %cx # length of btx client
+		rep				# Relocate the
+		movsb				#  simple BTX client
 /*
  * Copy the boot[12] args to where the BTX client can see them
  */
-		movw $MEM_ARG, %si		// where the args are at now
-		movw $MEM_ARG_BTX, %di		// where the args are moving to
-		movw $(MEM_ARG_SIZE/4), %cx	// size of the arguments in
-						//  longs
-		rep				// Relocate
-		movsl				//  the words
+		movw $MEM_ARG, %si		# where the args are at now
+		movw $MEM_ARG_BTX, %di		# where the args are moving to
+		movw $(MEM_ARG_SIZE/4), %cx	# size of the arguments in longs
+		rep				# Relocate
+		movsl				#  the words
 /*
  * Save the entry point so the client can get to it later on
  */
-		movl end+AOUT_ENTRY, %eax	// load the entry point
-		stosl				// add it to the end of the
-						//  arguments
+		movl end+AOUT_ENTRY, %eax	# load the entry point
+		stosl				# add it to the end of the
+						#  arguments
 /*
  * Now we just start up BTX and let it do the rest
  */
-		movw $jump_message, %si		// Display the
-		callw putstr			//  jump message
-		ljmp $0,$MEM_BTX_ENTRY		// Jump to the BTX entry point
+		movw $jump_message, %si		# Display the
+		callw putstr			#  jump message
+		ljmp $0,$MEM_BTX_ENTRY		# Jump to the BTX entry point
 
 /*
  * Display a null-terminated string
  */
-putstr:		lodsb				// load %al from %ds:(%si)
-		testb %al,%al			// stop at null
-		jnz putc			// if the char != null,
-						//  output it
-		retw				// return when null is hit
-putc:		movw $0x7,%bx			// attribute for output
-		movb $0xe,%ah			// BIOS: put_char
-		int $0x10			// call BIOS, print char in %al
-		jmp putstr			// keep looping
+putstr:		lodsb				# load %al from %ds:(%si)
+		testb %al,%al			# stop at null
+		jnz putc			# if the char != null, output it
+		retw				# return when null is hit
+putc:		movw $0x7,%bx			# attribute for output
+		movb $0xe,%ah			# BIOS: put_char
+		int $0x10			# call BIOS, print char in %al
+		jmp putstr			# keep looping
 
 /*
  * Enable A20
  */
-seta20: 	cli				// Disable interrupts
-seta20.1:	inb $0x64,%al			// Get status
-		testb $0x2,%al			// Busy?
-		jnz seta20.1			// Yes
-		movb $0xd1,%al			// Command: Write
-		outb %al,$0x64			//  output port
-seta20.2:	inb $0x64,%al			// Get status
-		testb $0x2,%al			// Busy?
-		jnz seta20.2			// Yes
-		movb $0xdf,%al			// Enable
-		outb %al,$0x60			//  A20
-		sti				// Enable interrupts
-		retw				// To caller
+seta20: 	cli				# Disable interrupts
+seta20.1:	inb $0x64,%al			# Get status
+		testb $0x2,%al			# Busy?
+		jnz seta20.1			# Yes
+		movb $0xd1,%al			# Command: Write
+		outb %al,$0x64			#  output port
+seta20.2:	inb $0x64,%al			# Get status
+		testb $0x2,%al			# Busy?
+		jnz seta20.2			# Yes
+		movb $0xdf,%al			# Enable
+		outb %al,$0x60			#  A20
+		sti				# Enable interrupts
+		retw				# To caller
 
 /*
  * BTX client to start btxldr
  */
 		.code32
 btx_client:	movl $(MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE-4), %esi
-						// %ds:(%esi) -> end
-						//  of boot[12] args
-		movl $(MEM_ARG_SIZE/4), %ecx	// Number of words to push
-		std				// Go backwards
-push_arg:	lodsl				// Read argument
-		pushl %eax			// Push it onto the stack
-		loop push_arg			// Push all of the arguments
-		cld				// In case anyone depends
-						//  on this
-		pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE // Entry point of
-						//  the loader
-		pushl %eax			// Emulate a near call
-		movl $0x1, %eax			// 'exec' system call
-		int $INT_SYS			// BTX system call
+						# %ds:(%esi) -> end
+						#  of boot[12] args
+		movl $(MEM_ARG_SIZE/4), %ecx	# Number of words to push
+		std				# Go backwards
+push_arg:	lodsl				# Read argument
+		pushl %eax			# Push it onto the stack
+		loop push_arg			# Push all of the arguments
+		cld				# In case anyone depends on this
+		pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE # Entry point of
+						#  the loader
+		pushl %eax			# Emulate a near call
+		movl $0x1, %eax			# 'exec' system call
+		int $INT_SYS			# BTX system call
 btx_client_end:
 		.code16
 
@@ -272,17 +268,17 @@ btx_client_end:
 /*
  * Global descriptor table.
  */
-gdt:		.word 0x0,0x0,0x0,0x0		// Null entry
-		.word 0xffff,0x0,0x9200,0xcf	// SEL_SDATA
-		.word 0xffff,0x0,0x9200,0x0	// SEL_RDATA
-		.word 0xffff,0x0,0x9a00,0xcf	// SEL_SCODE (32-bit)
-		.word 0xffff,0x0,0x9a00,0x8f	// SEL_SCODE16 (16-bit)
+gdt:		.word 0x0,0x0,0x0,0x0		# Null entry
+		.word 0xffff,0x0,0x9200,0xcf	# SEL_SDATA
+		.word 0xffff,0x0,0x9200,0x0	# SEL_RDATA
+		.word 0xffff,0x0,0x9a00,0xcf	# SEL_SCODE (32-bit)
+		.word 0xffff,0x0,0x9a00,0x8f	# SEL_SCODE16 (16-bit)
 gdt.1:
 /*
  * Pseudo-descriptors.
  */
-gdtdesc:	.word gdt.1-gdt-1		// Limit
-		.long gdt			// Base
+gdtdesc:	.word gdt.1-gdt-1		# Limit
+		.long gdt			# Base
 
 welcome_msg:	.asciz	"PXE Loader 1.00\r\n\n"
 bootinfo_msg:	.asciz	"Building the boot loader arguments\r\n"