diff options
| author | Aurelien Jacquiot <a-jacquiot@ti.com> | 2011-10-04 11:15:51 -0400 |
|---|---|---|
| committer | Mark Salter <msalter@redhat.com> | 2011-10-06 19:48:23 -0400 |
| commit | 09831ca73443bd819ad7993db5409b19c899ba33 (patch) | |
| tree | 4558fb0a5e0e1fcd8582be2155cd9c7498e429db /arch/c6x/lib/remi.S | |
| parent | a7f626c1948ab6178d2338831c5ffea7385e9f7f (diff) | |
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>
Diffstat (limited to 'arch/c6x/lib/remi.S')
| -rw-r--r-- | arch/c6x/lib/remi.S | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/c6x/lib/remi.S b/arch/c6x/lib/remi.S new file mode 100644 index 000000000000..6f2ca18c3f98 --- /dev/null +++ b/arch/c6x/lib/remi.S @@ -0,0 +1,64 @@ +;; Copyright 2010 Free Software Foundation, Inc. +;; Contributed by Bernd Schmidt <bernds@codesourcery.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> + + ;; ABI considerations for the divide functions + ;; The following registers are call-used: + ;; __c6xabi_divi A0,A1,A2,A4,A6,B0,B1,B2,B4,B5 + ;; __c6xabi_divu A0,A1,A2,A4,A6,B0,B1,B2,B4 + ;; __c6xabi_remi A1,A2,A4,A5,A6,B0,B1,B2,B4 + ;; __c6xabi_remu A1,A4,A5,A7,B0,B1,B2,B4 + ;; + ;; In our implementation, divu and remu are leaf functions, + ;; while both divi and remi call into divu. + ;; A0 is not clobbered by any of the functions. + ;; divu does not clobber B2 either, which is taken advantage of + ;; in remi. + ;; divi uses B5 to hold the original return address during + ;; the call to divu. + ;; remi uses B2 and A5 to hold the input values during the + ;; call to divu. It stores B3 in on the stack. + + .text + +ENTRY(__c6xabi_remi) + stw .d2t2 B3, *B15--[2] +|| cmpgt .l1 0, A4, A1 +|| cmpgt .l2 0, B4, B2 +|| mv .s1 A4, A5 +|| call .s2 __c6xabi_divu + + [A1] neg .l1 A4, A4 +|| [B2] neg .l2 B4, B4 +|| xor .s2x B2, A1, B0 +|| mv .d2 B4, B2 + + [B0] addkpc .s2 _divu_ret_1, B3, 1 + [!B0] addkpc .s2 _divu_ret_2, B3, 1 + nop 2 +_divu_ret_1: + neg .l1 A4, A4 +_divu_ret_2: + ldw .d2t2 *++B15[2], B3 + + mpy32 .m1x A4, B2, A6 + nop 3 + ret .s2 B3 + sub .l1 A5, A6, A4 + nop 4 +ENDPROC(__c6xabi_remi) |