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kernel/linux-imx6_3.14.28/arch/c6x/lib/mpyll.S 1.55 KB
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  ;;  Copyright (C) 2010 Texas Instruments Incorporated
  ;;  Contributed by Mark Salter <msalter@redhat.com>.
  ;;
  ;; This program is free software; you can redistribute it and/or modify
  ;; it under the terms of the GNU General Public License as published by
  ;; the Free Software Foundation; either version 2 of the License, or
  ;; (at your option) any later version.
  ;;
  ;; This program is distributed in the hope that it will be useful,
  ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ;; GNU General Public License for more details.
  ;;
  ;; You should have received a copy of the GNU General Public License
  ;; along with this program; if not, write to the Free Software
  ;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  
  #include <linux/linkage.h>
  
  	;; uint64_t __c6xabi_mpyll(uint64_t x, uint64_t y)
  	;;
  	;; 64x64 multiply
  	;; First compute partial results using 32-bit parts of x and y:
  	;;
  	;;   b63	 b32 b31	  b0
  	;;    -----------------------------
  	;;    |      1	    |	   0	  |
  	;;    -----------------------------
  	;;
  	;;   P0 = X0*Y0
  	;;   P1 = X0*Y1 + X1*Y0
  	;;   P2 = X1*Y1
  	;;
  	;;   result = (P2 << 64) + (P1 << 32) + P0
  	;;
  	;; Since the result is also 64-bit, we can skip the P2 term.
  
  	.text
  ENTRY(__c6xabi_mpyll)
  	mpy32u	.m1x	A4,B4,A1:A0	; X0*Y0
  	b	.s2	B3
   ||	mpy32u	.m2x	B5,A4,B1:B0	; X0*Y1 (don't need upper 32-bits)
   ||	mpy32u	.m1x	A5,B4,A3:A2	; X1*Y0 (don't need upper 32-bits)
  	nop
  	nop
  	mv	.s1	A0,A4
  	add	.l1x	A2,B0,A5
  	add	.s1	A1,A5,A5
  ENDPROC(__c6xabi_mpyll)