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write_rnd(3)
NAME
  write_rnd, read_rnd - Sets and returns IEEE dynamic rounding mode for
  floating-point operations

LIBRARY
  Standard C Library (libc.so, libc.a)

SYNOPSIS
  #include <float.h>

  unsigned int write_rnd(
	  unsigned int	rnd);

  unsigned int read_rnd();

DESCRIPTION
  The write_rnd function sets the dynamic rounding mode in the floating-point
  control register (fpcr) for IEEE floating-point operations and returns the
  previous dynamic rounding mode.  Dynamic rounding mode for IEEE floating-
  point operations is enabled for code generated by the C compiler by
  specifying -fprm d to cc(1), and by using the d floating-point instruction
  operator in assembly language code.

  Specify rnd as one of the following constants defined in float.h

  ______________________________________
  Constant    Meaning
  ______________________________________
  FP_RND_RZ

	      Round toward zero (chopped
	      rounding)

  FP_RND_RN

	      Round toward nearest
	      (normal rounding)

  FP_RND_RP

	      Round toward plus infinity

  FP_RND_RM

	      Round toward minus
	      infinity
  ______________________________________

  The read_rnd function returns the current dynamic rounding mode for
  floating-point operations.

RETURN VALUES
  The write_rnd function returns the previous IEEE floating-point rounding
  mode.	 The read_rnd function returns the current IEEE floating-point
  rounding mode.


RELATED INFORMATION
  Commands: cc(1).


  Files: float.h.

  Assembly Language Programmer's Guide.

  Alpha Architecture Reference Manual.

  IEEE Standard for Binary Floating-Point Arithmetic