[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>
diff --git a/arch/arm/lib/muldi3.S b/arch/arm/lib/muldi3.S
new file mode 100644
index 0000000..c7fbdf0
--- /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
+