u-boot/arch/arc/lib/memcmp.S
Igor Guryanov f958a91fa5 arc: memcmp - fix zero-delay loop utilization
It's prohibited to put branch instruction in the very end of zero-delay
loop. On execution this causes "Illegal instruction" exception.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Igor Guryanov <guryanov@synopsys.com>
2015-02-09 16:41:20 +03:00

123 lines
2.2 KiB
ArmAsm

/*
* Copyright (C) 2004, 2007-2010, 2011-2014 Synopsys, Inc. All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifdef __LITTLE_ENDIAN__
#define WORD2 r2
#define SHIFT r3
#else /* __BIG_ENDIAN__ */
#define WORD2 r3
#define SHIFT r2
#endif /* _ENDIAN__ */
.global memcmp
.align 4
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
lpne .Loop_end
ld_s WORD2, [%r0, 4]
ld_s %r12, [%r1, 4]
brne %r4, %r5, .Leven
ld.a %r4, [%r0, 8]
ld.a %r5, [%r1, 8]
brne WORD2, %r12, .Lodd
nop
.Loop_end:
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
lpne .Lbyte_end
ldb_s %r3, [%r0, 1]
ldb %r12, [%r1, 1]
brne %r4, %r5, .Lbyte_even
ldb.a %r4, [%r0, 2]
ldb.a %r5, [%r1, 2]
brne %r3, %r12, .Lbyte_odd
nop
.Lbyte_end:
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