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, 53 insertions, 0 deletions

diff --git a/arch/c6x/lib/divi.S b/arch/c6x/lib/divi.S
new file mode 100644
index 000000000000..4bde924f2a98
--- /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)