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linux-next/arch/arc/lib/memcmp.S
Vineet Gupta 8922bc3058 ARCv2: Adhere to Zero Delay loop restriction
Branch insn can't be scheduled as last insn of Zero Overhead loop

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-22 14:06:56 +05:30

153 lines
2.6 KiB
ArmAsm

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* 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 __LITTLE_ENDIAN__
#define WORD2 r2
#define SHIFT r3
#else /* BIG ENDIAN */
#define WORD2 r3
#define SHIFT r2
#endif
ENTRY(memcmp)
or r12,r0,r1
asl_s r12,r12,30
sub r3,r2,1
brls r2,r12,.Lbytewise
ld r4,[r0,0]
ld r5,[r1,0]
lsr.f lp_count,r3,3
#ifdef CONFIG_ISA_ARCV2
/* In ARCv2 a branch can't be the last instruction in a zero overhead
* loop.
* So we move the branch to the start of the loop, duplicate it
* after the end, and set up r12 so that the branch isn't taken
* initially.
*/
mov_s r12,WORD2
lpne .Loop_end
brne WORD2,r12,.Lodd
ld WORD2,[r0,4]
#else
lpne .Loop_end
ld_s WORD2,[r0,4]
#endif
ld_s r12,[r1,4]
brne r4,r5,.Leven
ld.a r4,[r0,8]
ld.a r5,[r1,8]
#ifdef CONFIG_ISA_ARCV2
.Loop_end:
brne WORD2,r12,.Lodd
#else
brne WORD2,r12,.Lodd
.Loop_end:
#endif
asl_s SHIFT,SHIFT,3
bhs_s .Last_cmp
brne r4,r5,.Leven
ld r4,[r0,4]
ld r5,[r1,4]
#ifdef __LITTLE_ENDIAN__
nop_s
; one more load latency cycle
.Last_cmp:
xor r0,r4,r5
bset r0,r0,SHIFT
sub_s r1,r0,1
bic_s r1,r1,r0
norm r1,r1
b.d .Leven_cmp
and r1,r1,24
.Leven:
xor r0,r4,r5
sub_s r1,r0,1
bic_s r1,r1,r0
norm r1,r1
; slow track insn
and r1,r1,24
.Leven_cmp:
asl r2,r4,r1
asl r12,r5,r1
lsr_s r2,r2,1
lsr_s r12,r12,1
j_s.d [blink]
sub r0,r2,r12
.balign 4
.Lodd:
xor r0,WORD2,r12
sub_s r1,r0,1
bic_s r1,r1,r0
norm r1,r1
; slow track insn
and r1,r1,24
asl_s r2,r2,r1
asl_s r12,r12,r1
lsr_s r2,r2,1
lsr_s r12,r12,1
j_s.d [blink]
sub r0,r2,r12
#else /* BIG ENDIAN */
.Last_cmp:
neg_s SHIFT,SHIFT
lsr r4,r4,SHIFT
lsr r5,r5,SHIFT
; slow track insn
.Leven:
sub.f r0,r4,r5
mov.ne r0,1
j_s.d [blink]
bset.cs r0,r0,31
.Lodd:
cmp_s WORD2,r12
mov_s r0,1
j_s.d [blink]
bset.cs r0,r0,31
#endif /* ENDIAN */
.balign 4
.Lbytewise:
breq r2,0,.Lnil
ldb r4,[r0,0]
ldb r5,[r1,0]
lsr.f lp_count,r3
#ifdef CONFIG_ISA_ARCV2
mov r12,r3
lpne .Lbyte_end
brne r3,r12,.Lbyte_odd
#else
lpne .Lbyte_end
#endif
ldb_s r3,[r0,1]
ldb r12,[r1,1]
brne r4,r5,.Lbyte_even
ldb.a r4,[r0,2]
ldb.a r5,[r1,2]
#ifdef CONFIG_ISA_ARCV2
.Lbyte_end:
brne r3,r12,.Lbyte_odd
#else
brne r3,r12,.Lbyte_odd
.Lbyte_end:
#endif
bcc .Lbyte_even
brne r4,r5,.Lbyte_even
ldb_s r3,[r0,1]
ldb_s r12,[r1,1]
.Lbyte_odd:
j_s.d [blink]
sub r0,r3,r12
.Lbyte_even:
j_s.d [blink]
sub r0,r4,r5
.Lnil:
j_s.d [blink]
mov r0,0
END(memcmp)