denormal.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
  4 *
  5 * Floating-point emulation code
  6 *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
  7 */
  8/*
  9 * BEGIN_DESC
 10 *
 11 *  File:
 12 *	@(#)	pa/fp/denormal.c		$ Revision: $
 13 *
 14 *  Purpose:
 15 *	<<please update with a synopsis of the functionality provided by this file>>
 16 *
 17 *  External Interfaces:
 18 *	<<the following list was autogenerated, please review>>
 19 *	dbl_denormalize(dbl_opndp1,dbl_opndp2,inexactflag,rmode)
 20 *	sgl_denormalize(sgl_opnd,inexactflag,rmode)
 21 *
 22 *  Internal Interfaces:
 23 *	<<please update>>
 24 *
 25 *  Theory:
 26 *	<<please update with a overview of the operation of this file>>
 27 *
 28 * END_DESC
 29*/
 30
 31
 32
 33#include "float.h"
 34#include "sgl_float.h"
 35#include "dbl_float.h"
 36#include "hppa.h"
 37#include <linux/kernel.h>
 38/* #include <machine/sys/mdep_private.h> */
 39
 40#undef Fpustatus_register
 41#define Fpustatus_register Fpu_register[0]
 42
 43void
 44sgl_denormalize(unsigned int *sgl_opnd, boolean *inexactflag, int rmode)
 45{
 46	unsigned int opnd;
 47	int sign, exponent;
 48	boolean guardbit = FALSE, stickybit, inexact;
 49
 50	opnd = *sgl_opnd;
 51	stickybit = *inexactflag;
 52        exponent = Sgl_exponent(opnd) - SGL_WRAP;
 53        sign = Sgl_sign(opnd);
 54	Sgl_denormalize(opnd,exponent,guardbit,stickybit,inexact);
 55	if (inexact) {
 56	    switch (rmode) {
 57	      case ROUNDPLUS:
 58		if (sign == 0) {
 59			Sgl_increment(opnd);
 60		}
 61		break;
 62	      case ROUNDMINUS:
 63		if (sign != 0) {
 64			Sgl_increment(opnd);
 65		}
 66		break;
 67	      case ROUNDNEAREST:
 68		if (guardbit && (stickybit || 
 69		       Sgl_isone_lowmantissa(opnd))) {
 70			   Sgl_increment(opnd);
 71		}
 72		break;
 73	    }
 74	}
 75	Sgl_set_sign(opnd,sign);
 76	*sgl_opnd = opnd;
 77	*inexactflag = inexact;
 78	return;
 79}
 80
 81void
 82dbl_denormalize(unsigned int *dbl_opndp1,
 83	unsigned int * dbl_opndp2,
 84	boolean *inexactflag,
 85	int rmode)
 86{
 87	unsigned int opndp1, opndp2;
 88	int sign, exponent;
 89	boolean guardbit = FALSE, stickybit, inexact;
 90
 91	opndp1 = *dbl_opndp1;
 92	opndp2 = *dbl_opndp2;
 93	stickybit = *inexactflag;
 94	exponent = Dbl_exponent(opndp1) - DBL_WRAP;
 95	sign = Dbl_sign(opndp1);
 96	Dbl_denormalize(opndp1,opndp2,exponent,guardbit,stickybit,inexact);
 97	if (inexact) {
 98	    switch (rmode) {
 99	      case ROUNDPLUS:
100		if (sign == 0) {
101			Dbl_increment(opndp1,opndp2);
102		}
103		break;
104	      case ROUNDMINUS:
105		if (sign != 0) {
106			Dbl_increment(opndp1,opndp2);
107		}
108		break;
109	      case ROUNDNEAREST:
110		if (guardbit && (stickybit || 
111		       Dbl_isone_lowmantissap2(opndp2))) {
112			   Dbl_increment(opndp1,opndp2);
113		}
114		break;
115	    }
116	}
117	Dbl_set_sign(opndp1,sign);
118	*dbl_opndp1 = opndp1;
119	*dbl_opndp2 = opndp2;
120	*inexactflag = inexact;
121	return;
122}