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Diffstat (limited to 'arch/c6x/lib/mpyll.S')

-rw-r--r-- | arch/c6x/lib/mpyll.S | 49 |

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/c6x/lib/mpyll.S b/arch/c6x/lib/mpyll.S new file mode 100644 index 00000000000..f1034418b4d --- /dev/null +++ b/arch/c6x/lib/mpyll.S @@ -0,0 +1,49 @@ +;; 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) |