root/arch/c6x/lib/mpyll.S

   1 ;; SPDX-License-Identifier: GPL-2.0-or-later
   2 ;;  Copyright (C) 2010 Texas Instruments Incorporated
   3 ;;  Contributed by Mark Salter <msalter@redhat.com>.
   4 ;;
   5 
   6 #include <linux/linkage.h>
   7 
   8         ;; uint64_t __c6xabi_mpyll(uint64_t x, uint64_t y)
   9         ;;
  10         ;; 64x64 multiply
  11         ;; First compute partial results using 32-bit parts of x and y:
  12         ;;
  13         ;;   b63         b32 b31          b0
  14         ;;    -----------------------------
  15         ;;    |      1      |      0      |
  16         ;;    -----------------------------
  17         ;;
  18         ;;   P0 = X0*Y0
  19         ;;   P1 = X0*Y1 + X1*Y0
  20         ;;   P2 = X1*Y1
  21         ;;
  22         ;;   result = (P2 << 64) + (P1 << 32) + P0
  23         ;;
  24         ;; Since the result is also 64-bit, we can skip the P2 term.
  25 
  26         .text
  27 ENTRY(__c6xabi_mpyll)
  28         mpy32u  .m1x    A4,B4,A1:A0     ; X0*Y0
  29         b       .s2     B3
  30  ||     mpy32u  .m2x    B5,A4,B1:B0     ; X0*Y1 (don't need upper 32-bits)
  31  ||     mpy32u  .m1x    A5,B4,A3:A2     ; X1*Y0 (don't need upper 32-bits)
  32         nop
  33         nop
  34         mv      .s1     A0,A4
  35         add     .l1x    A2,B0,A5
  36         add     .s1     A1,A5,A5
  37 ENDPROC(__c6xabi_mpyll)