/* $OpenBSD: reg_mul.c,v 1.1 1996/08/27 10:33:00 downsj Exp $ */ /* * reg_mul.c * * Multiply one FPU_REG by another, put the result in a destination FPU_REG. * * * Copyright (C) 1992,1993,1994 * W. Metzenthen, 22 Parker St, Ormond, Vic 3163, * Australia. E-mail billm@vaxc.cc.monash.edu.au * All rights reserved. * * This copyright notice covers the redistribution and use of the * FPU emulator developed by W. Metzenthen. It covers only its use * in the 386BSD, FreeBSD and NetBSD operating systems. Any other * use is not permitted under this copyright. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must include information specifying * that source code for the emulator is freely available and include * either: * a) an offer to provide the source code for a nominal distribution * fee, or * b) list at least two alternative methods whereby the source * can be obtained, e.g. a publically accessible bulletin board * and an anonymous ftp site from which the software can be * downloaded. * 3. All advertising materials specifically mentioning features or use of * this emulator must acknowledge that it was developed by W. Metzenthen. * 4. The name of W. Metzenthen may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * * The purpose of this copyright, based upon the Berkeley copyright, is to * ensure that the covered software remains freely available to everyone. * * The software (with necessary differences) is also available, but under * the terms of the GNU copyleft, for the Linux operating system and for * the djgpp ms-dos extender. * * W. Metzenthen June 1994. * * * $FreeBSD: reg_mul.c,v 1.3 1994/06/10 07:44:53 rich Exp $ * */ /*---------------------------------------------------------------------------+ | The destination may be any FPU_REG, including one of the source FPU_REGs. | +---------------------------------------------------------------------------*/ #include <gnu/arch/i386/fpemul/exception.h> #include <gnu/arch/i386/fpemul/reg_constant.h> #include <gnu/arch/i386/fpemul/fpu_emu.h> #include <gnu/arch/i386/fpemul/fpu_system.h> /* This routine must be called with non-empty source registers */ void reg_mul(FPU_REG * a, FPU_REG * b, FPU_REG * dest, unsigned int control_w) { char sign = (a->sign ^ b->sign); if (!(a->tag | b->tag)) { /* This should be the most common case */ reg_u_mul(a, b, dest, control_w); dest->sign = sign; return; } else if ((a->tag <= TW_Zero) && (b->tag <= TW_Zero)) { #ifdef DENORM_OPERAND if (((b->tag == TW_Valid) && (b->exp <= EXP_UNDER)) || ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER))) { if (denormal_operand()) return; } #endif /* DENORM_OPERAND */ /* Must have either both arguments == zero, or one * valid and the other zero. The result is therefore * zero. */ reg_move(&CONST_Z, dest); #ifdef PECULIAR_486 /* The 80486 book says that the answer is +0, but a * real 80486 appears to behave this way... */ dest->sign = sign; #endif /* PECULIAR_486 */ return; } #if 0 /* TW_Denormal is not used yet... perhaps * never will be. */ else if ((a->tag <= TW_Denormal) && (b->tag <= TW_Denormal)) { /* One or both arguments are de-normalized */ /* Internal de-normalized numbers are not * supported yet */ EXCEPTION(EX_INTERNAL | 0x105); reg_move(&CONST_Z, dest); } #endif else { /* Must have infinities, NaNs, etc */ if ((a->tag == TW_NaN) || (b->tag == TW_NaN)) { real_2op_NaN(a, b, dest); return; } else if (a->tag == TW_Infinity) { if (b->tag == TW_Zero) { arith_invalid(dest); return; } /* Zero*Infinity is invalid */ else { #ifdef DENORM_OPERAND if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) && denormal_operand()) return; #endif /* DENORM_OPERAND */ reg_move(a, dest); dest->sign = sign; } return; } else if (b->tag == TW_Infinity) { if (a->tag == TW_Zero) { arith_invalid(dest); return; } /* Zero*Infinity is * invalid */ else { #ifdef DENORM_OPERAND if ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER) && denormal_operand()) return; #endif /* DENORM_OPERAND */ reg_move(b, dest); dest->sign = sign; } return; } #ifdef PARANOID else { EXCEPTION(EX_INTERNAL | 0x102); } #endif /* PARANOID */ } }