C6X: library code

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

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
@@ -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)