/*
*
* (c) Copyright 1989 OPEN SOFTWARE FOUNDATION, INC.
* (c) Copyright 1989 HEWLETT-PACKARD COMPANY
* (c) Copyright 1989 DIGITAL EQUIPMENT CORPORATION
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this
* file for any purpose is hereby granted without fee, provided that
* the above copyright notices and this notice appears in all source
* code copies, and that none of the names of Open Software
* Foundation, Inc., Hewlett-Packard Company, or Digital Equipment
* Corporation be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission. Neither Open Software Foundation, Inc., Hewlett-
* Packard Company, nor Digital Equipment Corporation makes any
* representations about the suitability of this software for any
* purpose.
*
*/
/*
**
** NAME:
**
** upkvaxg.c
**
** FACILITY:
**
** IDL Stub Runtime Support
**
** ABSTRACT:
**
** This module contains code to extract information from a VAX
** g_floating number and to initialize an UNPACKED_REAL structure
** with those bits.
**
** This module is meant to be used as an include file.
**
** VERSION: DCE 1.0
**
*/
/*
**++
** Functional Description:
**
** This module contains code to extract information from a VAX
** g_floating number and to initialize an UNPACKED_REAL structure
** with those bits.
**
** See the header files for a description of the UNPACKED_REAL
** structure.
**
** A VAX g_floating number in (16 bit words) looks like:
**
** [0]: Sign bit, 11 exp bits (bias 1024), 4 fraction bits
** [1]: 16 more fraction bits
** [2]: 16 more fraction bits
** [3]: 16 more fraction bits
**
** 0.5 <= fraction < 1.0, MSB implicit
**
**
** Implicit parameters:
**
** input_value: a pointer to the input parameter.
**
** r: an UNPACKED_REAL structure
**
**--
*/
memcpy(&r[1], input_value, 8);
/* Initialize FLAGS and perhaps set NEGATIVE bit */
r[U_R_FLAGS] = (r[1] >> 15) & U_R_NEGATIVE;
/* Extract VAX biased exponent */
r[U_R_EXP] = (r[1] >> 4) & 0x000007FFL;
if (r[U_R_EXP] == 0) {
if (r[U_R_FLAGS])
r[U_R_FLAGS] |= U_R_INVALID;
else
r[U_R_FLAGS] = U_R_ZERO;
} else {
/* Adjust for VAX 16 bit floating format */
r[1] = ((r[1] << 16) | (r[1] >> 16));
r[2] = ((r[2] << 16) | (r[2] >> 16));
/* Add unpacked real bias and subtract VAX bias */
r[U_R_EXP] += (U_R_BIAS - 1024);
/* Set hidden bit */
r[1] |= 0x00100000L;
/* Left justify fraction bits */
r[1] <<= 11;
r[1] |= (r[2] >> 21);
r[2] <<= 11;
/* Clear uninitialized part of unpacked real */
r[3] = 0;
r[4] = 0;
}