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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 000000000000..f1034418b4db --- /dev/null +++ b/arch/c6x/lib/mpyll.S | |||
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| 1 | ;; Copyright (C) 2010 Texas Instruments Incorporated | ||
| 2 | ;; Contributed by Mark Salter <msalter@redhat.com>. | ||
| 3 | ;; | ||
| 4 | ;; This program is free software; you can redistribute it and/or modify | ||
| 5 | ;; it under the terms of the GNU General Public License as published by | ||
| 6 | ;; the Free Software Foundation; either version 2 of the License, or | ||
| 7 | ;; (at your option) any later version. | ||
| 8 | ;; | ||
| 9 | ;; This program is distributed in the hope that it will be useful, | ||
| 10 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 11 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| 12 | ;; GNU General Public License for more details. | ||
| 13 | ;; | ||
| 14 | ;; You should have received a copy of the GNU General Public License | ||
| 15 | ;; along with this program; if not, write to the Free Software | ||
| 16 | ;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | ||
| 17 | |||
| 18 | #include <linux/linkage.h> | ||
| 19 | |||
| 20 | ;; uint64_t __c6xabi_mpyll(uint64_t x, uint64_t y) | ||
| 21 | ;; | ||
| 22 | ;; 64x64 multiply | ||
| 23 | ;; First compute partial results using 32-bit parts of x and y: | ||
| 24 | ;; | ||
| 25 | ;; b63 b32 b31 b0 | ||
| 26 | ;; ----------------------------- | ||
| 27 | ;; | 1 | 0 | | ||
| 28 | ;; ----------------------------- | ||
| 29 | ;; | ||
| 30 | ;; P0 = X0*Y0 | ||
| 31 | ;; P1 = X0*Y1 + X1*Y0 | ||
| 32 | ;; P2 = X1*Y1 | ||
| 33 | ;; | ||
| 34 | ;; result = (P2 << 64) + (P1 << 32) + P0 | ||
| 35 | ;; | ||
| 36 | ;; Since the result is also 64-bit, we can skip the P2 term. | ||
| 37 | |||
| 38 | .text | ||
| 39 | ENTRY(__c6xabi_mpyll) | ||
| 40 | mpy32u .m1x A4,B4,A1:A0 ; X0*Y0 | ||
| 41 | b .s2 B3 | ||
| 42 | || mpy32u .m2x B5,A4,B1:B0 ; X0*Y1 (don't need upper 32-bits) | ||
| 43 | || mpy32u .m1x A5,B4,A3:A2 ; X1*Y0 (don't need upper 32-bits) | ||
| 44 | nop | ||
| 45 | nop | ||
| 46 | mv .s1 A0,A4 | ||
| 47 | add .l1x A2,B0,A5 | ||
| 48 | add .s1 A1,A5,A5 | ||
| 49 | ENDPROC(__c6xabi_mpyll) | ||