Bug 19969

When trying to build a custom kernel with the following config file:#
# SHASTA -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
#    http://www.FreeBSD.org/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ./LINT configuration file. If you are
# in doubt as to the purpose or necessity of a line, check first in LINT.
#
# $FreeBSD: src/sys/i386/conf/SHASTA,v 1.246.2.6 2000/06/22 06:03:12 peter Exp $

machine         i386
cpu             I486_CPU
ident           SHASTA
maxusers        32

# Include text of this file in compiled kernel
options         INCLUDE_CONFIG_FILE


options         MATH_EMULATE            #Support for x87 emulation
options         INET                    #InterNETworking
options         FFS                     #Berkeley Fast Filesystem
options         FFS_ROOT                #FFS usable as root device [keep this!]
options         SOFTUPDATES             #Enable FFS soft updates support
options         MFS                     #Memory Filesystem
options         NFS                     #Network Filesystem
options         NFS_ROOT                #NFS usable as root device, NFS required
options         MSDOSFS                 #MSDOS Filesystem
options         CD9660                  #ISO 9660 Filesystem
options         CD9660_ROOT             #CD-ROM usable as root, CD9660 required
options         PROCFS                  #Process filesystem
options         COMPAT_43               #Compatible with BSD 4.3 [KEEP THIS!]
options         SCSI_DELAY=15000        #Delay (in ms) before probing SCSI
options         UCONSOLE                #Allow users to grab the console
options         USERCONFIG              #boot -c editor
options         VISUAL_USERCONFIG       #visual boot -c editor
options         KTRACE                  #ktrace(1) support
options         SYSVSHM                 #SYSV-style shared memory
options         SYSVMSG                 #SYSV-style message queues
options         SYSVSEM                 #SYSV-style semaphores
options         P1003_1B                #Posix P1003_1B real-time extensions
options         _KPOSIX_PRIORITY_SCHEDULING
options         ICMP_BANDLIM            #Rate limit bad replies
options         KBD_INSTALL_CDEV        # install a CDEV entry in /dev

device          isa
device          pci

# Floppy drives
device          fdc0    at isa? port IO_FD1 irq 6 drq 2
device          fd0     at fdc0 drive 0

# ATA and ATAPI devices
device          ata0    at isa? port IO_WD1 irq 14
device          ata1    at isa? port IO_WD2 irq 15
device          ata
device          atadisk                 # ATA disk drives
device          atapicd                 # ATAPI CDROM drives
options         ATA_STATIC_ID           #Static device numbering

# atkbdc0 controls both the keyboard and the PS/2 mouse
device          atkbdc0 at isa? port IO_KBD
device          atkbd0  at atkbdc? irq 1 flags 0x1

device          vga0    at isa?

# splash screen/screen saver
pseudo-device   splash

# syscons is the default console driver, resembling an SCO console
device          sc0     at isa? flags 0x100

options         XSERVER                 # support for X server on a vt console

# Floating point support - do not disable.
device          npx0    at nexus? port IO_NPX irq 13

# Power management support (see LINT for more options)
device          apm0    at nexus? disable flags 0x20 # Advanced Power Management

# Serial (COM) ports
device          sio0    at isa? port IO_COM1 flags 0x10 irq 4
device          sio1    at isa? port IO_COM2 irq 3

# Parallel port
device          ppc0    at isa? irq 7
device          ppbus           # Parallel port bus (required)
device          lpt             # Printer
device          plip            # TCP/IP over parallel
device          ppi             # Parallel port interface device


# PCI Ethernet NICs.
device          ep

# Pseudo devices - the number indicates how many units to allocated.
pseudo-device   loop            # Network loopback
pseudo-device   ether           # Ethernet support
pseudo-device   ppp     1       # Kernel PPP
pseudo-device   tun             # Packet tunnel.
pseudo-device   pty             # Pseudo-ttys (telnet etc)

# The `bpf' pseudo-device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
pseudo-device   bpf             #Berkeley packet filter

device          pcm
device          sbc


the compile progresses to
cc -c -x assembler-with-cpp -DLOCORE -O -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual -fformat-extensions -ansi -nostdinc -I- -I. -I../.. -I../../../include -D_KERNEL -include opt_global.h -elf -mpreferred-stack-boundary=2 ../../i386/i386/bioscall.s
/tmp/cciS5737.s: Assembler messages:
/tmp/cciS5737.s:773: Error: operands given don't match any known 386 instruction
/tmp/cciS5737.s:838: Error: operands given don't match any known 386 instruction

*** Error code 1

Stop in /usr/src/sys/compile/SHASTA.
shasta#

How-To-Repeat: See above.  Build that kernel.