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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/h8300/lib/mulsi3.S
parentInitial commit. (diff)
downloadlinux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz
linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/h8300/lib/mulsi3.S')
-rw-r--r--arch/h8300/lib/mulsi3.S39
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/h8300/lib/mulsi3.S b/arch/h8300/lib/mulsi3.S
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+; SPDX-License-Identifier: GPL-2.0
+;
+; mulsi3 for H8/300H - based on Renesas SH implementation
+;
+; by Toshiyasu Morita
+;
+; Old code:
+;
+; 16b * 16b = 372 states (worst case)
+; 32b * 32b = 724 states (worst case)
+;
+; New code:
+;
+; 16b * 16b = 48 states
+; 16b * 32b = 72 states
+; 32b * 32b = 92 states
+;
+
+ .global __mulsi3
+__mulsi3:
+ mov.w r1,r2 ; ( 2 states) b * d
+ mulxu r0,er2 ; (22 states)
+
+ mov.w e0,r3 ; ( 2 states) a * d
+ beq L_skip1 ; ( 4 states)
+ mulxu r1,er3 ; (22 states)
+ add.w r3,e2 ; ( 2 states)
+
+L_skip1:
+ mov.w e1,r3 ; ( 2 states) c * b
+ beq L_skip2 ; ( 4 states)
+ mulxu r0,er3 ; (22 states)
+ add.w r3,e2 ; ( 2 states)
+
+L_skip2:
+ mov.l er2,er0 ; ( 2 states)
+ rts ; (10 states)
+
+ .end