/******************************************************************************/
/* */
/* 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 */
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/******************************************************************************/
/***************************************************************************
****************************************************************************
***
*** Program File: @(#)expconstadd.v
***
****************************************************************************
****************************************************************************/
// @(#)expconstadd.v 1.1 4/11/92
//
// **************************************************************
// expconstadd -- carry-save add of a constant, a+b+C, where C is
// either 2's complement 127 (single), 2's complement 1023 (double),
// or 769 (fsmuld).
// It uses 5-bits of carry save adders, and 6-bits of half-adders.
//
// **************************************************************
module expconstadd
(sum,
cout,
a,
b,
fpm_inst
);
output [12:0] sum
;
output [12:0] cout
;
input [10:0] a
, b
;
input [1:0] fpm_inst
; // FMULs=00, FMULd=01, FsMULd=10
ME_TIEOFF t1 (VDD
, GND
);
// 2's complement 127 = 13'b1111110000001
// 2's complement 1023 = 13'b1110000000001
// 769 = 13'b0001100000001
wire c12_10
= ~fpm_inst[1] ;
wire c9_8
= ~fpm_inst[0] ;
wire c7
= ~(fpm_inst[0] | fpm_inst[1]) ;
add2 a0 ( sum[ 0], cout[ 1], a[ 0], b[ 0], VDD );
half_adder a1 ( sum[ 1], cout[ 2], a[ 1], b[ 1] );
half_adder a2 ( sum[ 2], cout[ 3], a[ 2], b[ 2] );
half_adder a3 ( sum[ 3], cout[ 4], a[ 3], b[ 3] );
half_adder a4 ( sum[ 4], cout[ 5], a[ 4], b[ 4] );
half_adder a5 ( sum[ 5], cout[ 6], a[ 5], b[ 5] );
half_adder a6 ( sum[ 6], cout[ 7], a[ 6], b[ 6] );
add2 a7 ( sum[ 7], cout[ 8], a[ 7], b[ 7], c7 );
add2 a8 ( sum[ 8], cout[ 9], a[ 8], b[ 8], c9_8 );
add2 a9 ( sum[ 9], cout[10], a[ 9], b[ 9], c9_8 );
add2 a10 ( sum[10], cout[11], a[10], b[10], c12_10 );
assign sum[12:11] = {c12_10, c12_10} ;
assign cout[12] = GND ;
assign cout[ 0] = GND ;
endmodule
This page: |
Created: | Thu Aug 19 12:03:30 1999 |
| From: |
../../../sparc_v8/ssparc/fpu/fp_fpm/rtl/expconstadd.v
|