From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Sat, 16 Apr 2005 15:20:36 -0700
Subject: Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
---
 arch/sparc/lib/mul.S | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 arch/sparc/lib/mul.S

(limited to 'arch/sparc/lib/mul.S')

diff --git a/arch/sparc/lib/mul.S b/arch/sparc/lib/mul.S
new file mode 100644
index 000000000000..83dffbc2f62f
--- /dev/null
+++ b/arch/sparc/lib/mul.S
@@ -0,0 +1,135 @@
+/* $Id: mul.S,v 1.4 1996/09/30 02:22:32 davem Exp $
+ * mul.S:       This routine was taken from glibc-1.09 and is covered
+ *              by the GNU Library General Public License Version 2.
+ */
+
+/*
+ * Signed multiply, from Appendix E of the Sparc Version 8
+ * Architecture Manual.
+ */
+
+/*
+ * Returns %o0 * %o1 in %o1%o0 (i.e., %o1 holds the upper 32 bits of
+ * the 64-bit product).
+ *
+ * This code optimizes short (less than 13-bit) multiplies.
+ */
+
+	.globl .mul
+.mul:
+	mov	%o0, %y		! multiplier -> Y
+	andncc	%o0, 0xfff, %g0	! test bits 12..31
+	be	Lmul_shortway	! if zero, can do it the short way
+	 andcc	%g0, %g0, %o4	! zero the partial product and clear N and V
+
+	/*
+	 * Long multiply.  32 steps, followed by a final shift step.
+	 */
+	mulscc	%o4, %o1, %o4	! 1
+	mulscc	%o4, %o1, %o4	! 2
+	mulscc	%o4, %o1, %o4	! 3
+	mulscc	%o4, %o1, %o4	! 4
+	mulscc	%o4, %o1, %o4	! 5
+	mulscc	%o4, %o1, %o4	! 6
+	mulscc	%o4, %o1, %o4	! 7
+	mulscc	%o4, %o1, %o4	! 8
+	mulscc	%o4, %o1, %o4	! 9
+	mulscc	%o4, %o1, %o4	! 10
+	mulscc	%o4, %o1, %o4	! 11
+	mulscc	%o4, %o1, %o4	! 12
+	mulscc	%o4, %o1, %o4	! 13
+	mulscc	%o4, %o1, %o4	! 14
+	mulscc	%o4, %o1, %o4	! 15
+	mulscc	%o4, %o1, %o4	! 16
+	mulscc	%o4, %o1, %o4	! 17
+	mulscc	%o4, %o1, %o4	! 18
+	mulscc	%o4, %o1, %o4	! 19
+	mulscc	%o4, %o1, %o4	! 20
+	mulscc	%o4, %o1, %o4	! 21
+	mulscc	%o4, %o1, %o4	! 22
+	mulscc	%o4, %o1, %o4	! 23
+	mulscc	%o4, %o1, %o4	! 24
+	mulscc	%o4, %o1, %o4	! 25
+	mulscc	%o4, %o1, %o4	! 26
+	mulscc	%o4, %o1, %o4	! 27
+	mulscc	%o4, %o1, %o4	! 28
+	mulscc	%o4, %o1, %o4	! 29
+	mulscc	%o4, %o1, %o4	! 30
+	mulscc	%o4, %o1, %o4	! 31
+	mulscc	%o4, %o1, %o4	! 32
+	mulscc	%o4, %g0, %o4	! final shift
+
+	! If %o0 was negative, the result is
+	!	(%o0 * %o1) + (%o1 << 32))
+	! We fix that here.
+
+#if 0
+	tst	%o0
+	bge	1f
+	 rd	%y, %o0
+
+	! %o0 was indeed negative; fix upper 32 bits of result by subtracting 
+	! %o1 (i.e., return %o4 - %o1 in %o1).
+	retl
+	 sub	%o4, %o1, %o1
+
+1:
+	retl
+	 mov	%o4, %o1
+#else
+	/* Faster code adapted from tege@sics.se's code for umul.S.  */
+	sra	%o0, 31, %o2	! make mask from sign bit
+	and	%o1, %o2, %o2	! %o2 = 0 or %o1, depending on sign of %o0
+	rd	%y, %o0		! get lower half of product
+	retl
+	 sub	%o4, %o2, %o1	! subtract compensation 
+				!  and put upper half in place
+#endif
+
+Lmul_shortway:
+	/*
+	 * Short multiply.  12 steps, followed by a final shift step.
+	 * The resulting bits are off by 12 and (32-12) = 20 bit positions,
+	 * but there is no problem with %o0 being negative (unlike above).
+	 */
+	mulscc	%o4, %o1, %o4	! 1
+	mulscc	%o4, %o1, %o4	! 2
+	mulscc	%o4, %o1, %o4	! 3
+	mulscc	%o4, %o1, %o4	! 4
+	mulscc	%o4, %o1, %o4	! 5
+	mulscc	%o4, %o1, %o4	! 6
+	mulscc	%o4, %o1, %o4	! 7
+	mulscc	%o4, %o1, %o4	! 8
+	mulscc	%o4, %o1, %o4	! 9
+	mulscc	%o4, %o1, %o4	! 10
+	mulscc	%o4, %o1, %o4	! 11
+	mulscc	%o4, %o1, %o4	! 12
+	mulscc	%o4, %g0, %o4	! final shift
+
+	/*
+	 *  %o4 has 20 of the bits that should be in the low part of the
+	 * result; %y has the bottom 12 (as %y's top 12).  That is:
+	 *
+	 *	  %o4		    %y
+	 * +----------------+----------------+
+	 * | -12- |   -20-  | -12- |   -20-  |
+	 * +------(---------+------)---------+
+	 *  --hi-- ----low-part----
+	 *
+	 * The upper 12 bits of %o4 should be sign-extended to form the
+	 * high part of the product (i.e., highpart = %o4 >> 20).
+	 */
+
+	rd	%y, %o5
+	sll	%o4, 12, %o0	! shift middle bits left 12
+	srl	%o5, 20, %o5	! shift low bits right 20, zero fill at left
+	or	%o5, %o0, %o0	! construct low part of result
+	retl
+	 sra	%o4, 20, %o1	! ... and extract high part of result
+
+	.globl	.mul_patch
+.mul_patch:
+	smul	%o0, %o1, %o0
+	retl
+	 rd	%y, %o1
+	nop
-- 
cgit v1.2.3