[ARM] 3049/1: More optimized libgcc functions

Patch from Nicolas Pitre

This patch gets rid of the last C implementations of needed libgcc
functions for the kernel, replacing them with optimized assembly
versions.

Those functions are:

__ashldi3
__ashrdi3
__lshrdi3
__muldi3
__ucmpdi2

The first 3 were lifted from gcc, the other two were written from scratch.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/arm/lib/muldi3.S b/arch/arm/lib/muldi3.S
new file mode 100644
index 000000000000..c7fbdf005319
--- /dev/null
+++ b/arch/arm/lib/muldi3.S
@@ -0,0 +1,44 @@
+/*
+ *  linux/arch/arm/lib/muldi3.S
+ *
+ *  Author:     Nicolas Pitre
+ *  Created:    Oct 19, 2005
+ *  Copyright:  Monta Vista Software, Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+
+#ifdef __ARMEB__
+#define xh r0
+#define xl r1
+#define yh r2
+#define yl r3
+#else
+#define xl r0
+#define xh r1
+#define yl r2
+#define yh r3
+#endif
+
+ENTRY(__muldi3)
+
+        mul     xh, yl, xh
+        mla     xh, xl, yh, xh
+        mov     ip, xl, asr #16
+        mov     yh, yl, asr #16
+        bic     xl, xl, ip, lsl #16
+        bic     yl, yl, yh, lsl #16
+        mla     xh, yh, ip, xh
+        mul     yh, xl, yh
+        mul     xl, yl, xl
+        mul     ip, yl, ip
+        adds    xl, xl, yh, lsl #16
+        adc     xh, xh, yh, lsr #16
+        adds    xl, xl, ip, lsl #16
+        adc     xh, xh, ip, lsr #16
+        mov     pc, lr
+