/******************************************************************************/
/* */
/* Copyright (c) 1999 Sun Microsystems, Inc. All rights reserved. */
/* */
/* The contents of this file are subject to the current version of the Sun */
/* Community Source License, microSPARCII ("the License"). You may not use */
/* this file except in compliance with the License. You may obtain a copy */
/* of the License by searching for "Sun Community Source License" on the */
/* World Wide Web at http://www.sun.com. See the License for the rights, */
/* obligations, and limitations governing use of the contents of this file. */
/* */
/* Sun Microsystems, Inc. has intellectual property rights relating to the */
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/* these intellectual property rights may include one or more U.S. patents, */
/* foreign patents, or pending applications. */
/* */
/* Sun, Sun Microsystems, the Sun logo, all Sun-based trademarks and logos, */
/* Solaris, Java and all Java-based trademarks and logos are trademarks or */
/* registered trademarks of Sun Microsystems, Inc. in the United States and */
/* other countries. microSPARC is a trademark or registered trademark of */
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/* */
/******************************************************************************/
// @(#)preventswapctl.v 1.1 4/7/92
//
module PreventSwapCtl
(FracAgtB, notExpAgtB, ExpZero,
RomPrevIfBgtA, FpLd,
PreventSwap,
PreventSwapExp);
input FracAgtB
, notExpAgtB
, ExpZero
,
FpLd
, RomPrevIfBgtA
;
output PreventSwap
;
output PreventSwapExp
;
// Preventing swap on add
// Use seperate line for Exp
ME_INV_A psg0 (FpLd, notFpLd
); // On FpLd remove prevent swap
ME_INV_A psg3 (ExpZero, notExpZero
);
ME_NAND3_B psg4 (notFpLd, RomPrevIfBgtA, notExpAgtB, notPrevSwap_F0
);
ME_NAND4 psg5 (notFpLd, RomPrevIfBgtA, notExpAgtB, notExpZero, notPrevSwap_F1
);
ME_NMUX2B_B psg6 (FracAgtB, notPrevSwap_F0, notPrevSwap_F1, PreventSwap);
// Add seperate PreventSwap for Exp
ME_INV_B psg7 (notPrevSwap_F0, PreventSwapExp);
//ME_XOR psg8 (PreventSwapExp, PreventSwap, WrongSwap);
//ME_FD1 psg8 (Phi, WrongSwap, L_WrongSwap, ); // So swap back !!
/* **************************************************** /
/ We know that we've done the wrong swap. Since the
/ swap is only done at the begining of add we can be sure
/ that FracAreg is going to be loaded from the shifter on
/ the subsequent cycle. So we can force it to be loaded from
/ Breg and also force Breg to be loaded from Areg. So that
/ if a swap was prevented it can be redone
* **************************************************** */
endmodule
This page: |
Created: | Thu Aug 19 12:03:14 1999 |
| From: |
../../../sparc_v8/ssparc/fpu/fp_ctl/rtl/preventswapctl.v
|