| GENASSYM.CF(5) | File Formats Manual | GENASSYM.CF(5) | 
genassym.cf —
assym.h definition file
The genassym.cf file is used by
  genassym(1) to make constant C
  expressions known to assembler source files. Lines starting with '#' are
  discarded by genassym(1).
  Lines starting with include, ifdef,
  if, else or endif are
  preceded with '#' and passed otherwise unmodified to the C compiler. Lines
  starting with quote get passed on with the
  quote command removed. The first word after a
  define command is taken as a CPP identifier and the rest of
  the line has to be a constant C expression. The output of
  genassym(1) will assign the
  numerical value of this expression to the CPP identifier. export
  X is a shorthand for define X X. struct
  X remembers X for the member command and does a
  define X_SIZEOF sizeof(X). member X does a
  define X offsetof(<last struct>, X).
  config <ctype> <gcc constraint> <asm print
  modifier> can be used to customize the output of
  genassym(1). When producing C
  output, values are casted to <ctype> (default: long) before they get
  handed to printf. <gcc constraint> (default: n) is the constraint used
  in the __asm__ statements. <asm print modifier> (default: empty) can be
  used to force gcc to output operands in different ways then normal. The
  "a" modifier e.g. stops gcc from emitting immediate prefixes in
  front of constants for the i386 and m68k port.
/usr/src/sys/arch/${MACHINE}/${MACHINE}/genassym.cf
The genassym.cf file appeared in NetBSD
  1.3.