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Diffstat (limited to 'kernel/arch/c6x/lib/divi.S')
| -rw-r--r-- | kernel/arch/c6x/lib/divi.S | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/kernel/arch/c6x/lib/divi.S b/kernel/arch/c6x/lib/divi.S new file mode 100644 index 000000000..4bde924f2 --- /dev/null +++ b/kernel/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) |