diff options
Diffstat (limited to 'sys/gnu/i386/fpemul/reg_mul.c')
| -rw-r--r-- | sys/gnu/i386/fpemul/reg_mul.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/sys/gnu/i386/fpemul/reg_mul.c b/sys/gnu/i386/fpemul/reg_mul.c new file mode 100644 index 0000000..4ae5fb3 --- /dev/null +++ b/sys/gnu/i386/fpemul/reg_mul.c @@ -0,0 +1,149 @@ +/* + * reg_mul.c + * + * Multiply one FPU_REG by another, put the result in a destination FPU_REG. + * + * + * Copyright (C) 1992, 1993 W. Metzenthen, 22 Parker St, Ormond, + * Vic 3163, Australia. + * E-mail apm233m@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 operating system. 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 destination may be any FPU_REG, including one of the source FPU_REGs. | + +---------------------------------------------------------------------------*/ + +#include "exception.h" +#include "reg_constant.h" +#include "fpu_emu.h" +#include "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 */ + } +} |
