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, 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)