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>
diff --git a/arch/c6x/lib/divi.S b/arch/c6x/lib/divi.S
new file mode 100644
index 0000000..4bde924
--- /dev/null
+++ b/arch/c6x/lib/divi.S
@@ -0,0 +1,53 @@
+;; 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_divi)
+ call .s2 __c6xabi_divu
+|| mv .d2 B3, B5
+|| cmpgt .l1 0, A4, A1
+|| cmpgt .l2 0, B4, B1
+
+ [A1] neg .l1 A4, A4
+|| [B1] neg .l2 B4, B4
+|| xor .s1x A1, B1, A1
+ [A1] addkpc .s2 _divu_ret, B3, 4
+_divu_ret:
+ neg .l1 A4, A4
+|| mv .l2 B3,B5
+|| ret .s2 B5
+ nop 5
+ENDPROC(__c6xabi_divi)