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linux/arch/sh/lib/memcpy-sh4.S
Hideo Saito e08b954c9a sh: Fix up optimized SH-4 memcpy on big endian. 
Signed-off-by: Hideo Saito <saito@densan.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-05-16 14:55:07 +09:00

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/*
* "memcpy" implementation of SuperH
*
* Copyright (C) 1999 Niibe Yutaka
* Copyright (c) 2002 STMicroelectronics Ltd
* Modified from memcpy.S and micro-optimised for SH4
* Stuart Menefy (stuart.menefy@st.com)
*
*/
#include <linux/linkage.h>
/*
* void *memcpy(void *dst, const void *src, size_t n);
*
* It is assumed that there is no overlap between src and dst.
* If there is an overlap, then the results are undefined.
*/
!
! GHIJ KLMN OPQR --> ...G HIJK LMNO PQR.
!
! Size is 16 or greater, and may have trailing bytes
.balign 32
.Lcase1:
! Read a long word and write a long word at once
! At the start of each iteration, r7 contains last long load
add #-1,r5 ! 79 EX
mov r4,r2 ! 5 MT (0 cycles latency)
mov.l @(r0,r5),r7 ! 21 LS (2 cycles latency)
add #-4,r5 ! 50 EX
add #7,r2 ! 79 EX
!
#ifdef CONFIG_CPU_LITTLE_ENDIAN
! 6 cycles, 4 bytes per iteration
3: mov.l @(r0,r5),r1 ! 21 LS (latency=2) ! NMLK
mov r7, r3 ! 5 MT (latency=0) ! RQPO
cmp/hi r2,r0 ! 57 MT
shll16 r3 ! 103 EX
mov r1,r6 ! 5 MT (latency=0)
shll8 r3 ! 102 EX ! Oxxx
shlr8 r6 ! 106 EX ! xNML
mov r1, r7 ! 5 MT (latency=0)
or r6,r3 ! 82 EX ! ONML
bt/s 3b ! 109 BR
mov.l r3,@-r0 ! 30 LS
#else
3: mov.l @(r0,r5),r1 ! 21 LS (latency=2) ! KLMN
mov r7,r3 ! 5 MT (latency=0) ! OPQR
cmp/hi r2,r0 ! 57 MT
shlr16 r3 ! 107 EX
shlr8 r3 ! 106 EX ! xxxO
mov r1,r6 ! 5 MT (latency=0)
shll8 r6 ! 102 EX ! LMNx
mov r1,r7 ! 5 MT (latency=0)
or r6,r3 ! 82 EX ! LMNO
bt/s 3b ! 109 BR
mov.l r3,@-r0 ! 30 LS
#endif
! Finally, copy a byte at once, if necessary
add #4,r5 ! 50 EX
cmp/eq r4,r0 ! 54 MT
add #-6,r2 ! 50 EX
bt 9f ! 109 BR
8: cmp/hi r2,r0 ! 57 MT
mov.b @(r0,r5),r1 ! 20 LS (latency=2)
bt/s 8b ! 109 BR
mov.b r1,@-r0 ! 29 LS
9: rts
nop
!
! GHIJ KLMN OPQR --> .GHI JKLM NOPQ R...
!
! Size is 16 or greater, and may have trailing bytes
.balign 32
.Lcase3:
! Read a long word and write a long word at once
! At the start of each iteration, r7 contains last long load
add #-3,r5 ! 79 EX
mov r4,r2 ! 5 MT (0 cycles latency)
mov.l @(r0,r5),r7 ! 21 LS (2 cycles latency)
add #-4,r5 ! 50 EX
add #7,r2 ! 79 EX
!
#ifdef CONFIG_CPU_LITTLE_ENDIAN
! 6 cycles, 4 bytes per iteration
3: mov.l @(r0,r5),r1 ! 21 LS (latency=2) ! NMLK
mov r7, r3 ! 5 MT (latency=0) ! RQPO
cmp/hi r2,r0 ! 57 MT
shll8 r3 ! 102 EX ! QPOx
mov r1,r6 ! 5 MT (latency=0)
shlr16 r6 ! 107 EX
shlr8 r6 ! 106 EX ! xxxN
mov r1, r7 ! 5 MT (latency=0)
or r6,r3 ! 82 EX ! QPON
bt/s 3b ! 109 BR
mov.l r3,@-r0 ! 30 LS
#else
3: mov r7,r3 ! OPQR
shlr8 r3 ! xOPQ
mov.l @(r0,r5),r7 ! KLMN
mov r7,r6
shll16 r6
shll8 r6 ! Nxxx
or r6,r3 ! NOPQ
cmp/hi r2,r0
bt/s 3b
mov.l r3,@-r0
#endif
! Finally, copy a byte at once, if necessary
add #6,r5 ! 50 EX
cmp/eq r4,r0 ! 54 MT
add #-6,r2 ! 50 EX
bt 9f ! 109 BR
8: cmp/hi r2,r0 ! 57 MT
mov.b @(r0,r5),r1 ! 20 LS (latency=2)
bt/s 8b ! 109 BR
mov.b r1,@-r0 ! 29 LS
9: rts
nop
ENTRY(memcpy)
! Calculate the invariants which will be used in the remainder
! of the code:
!
! r4 --> [ ... ] DST [ ... ] SRC
! [ ... ] [ ... ]
! : :
! r0 --> [ ... ] r0+r5 --> [ ... ]
!
!
! Short circuit the common case of src, dst and len being 32 bit aligned
! and test for zero length move
mov r6, r0 ! 5 MT (0 cycle latency)
or r4, r0 ! 82 EX
or r5, r0 ! 82 EX
tst r6, r6 ! 86 MT
bt/s 99f ! 111 BR (zero len)
tst #3, r0 ! 87 MT
mov r4, r0 ! 5 MT (0 cycle latency)
add r6, r0 ! 49 EX
mov #16, r1 ! 6 EX
bt/s .Lcase00 ! 111 BR (aligned)
sub r4, r5 ! 75 EX
! Arguments are not nicely long word aligned or zero len.
! Check for small copies, and if so do a simple byte at a time copy.
!
! Deciding on an exact value of 'small' is not easy, as the point at which
! using the optimised routines become worthwhile varies (these are the
! cycle counts for differnet sizes using byte-at-a-time vs. optimised):
! size byte-at-time long word byte
! 16 42 39-40 46-50 50-55
! 24 58 43-44 54-58 62-67
! 36 82 49-50 66-70 80-85
! However the penalty for getting it 'wrong' is much higher for long word
! aligned data (and this is more common), so use a value of 16.
cmp/gt r6,r1 ! 56 MT
add #-1,r5 ! 50 EX
bf/s 6f ! 108 BR (not small)
mov r5, r3 ! 5 MT (latency=0)
shlr r6 ! 104 EX
mov.b @(r0,r5),r1 ! 20 LS (latency=2)
bf/s 4f ! 111 BR
add #-1,r3 ! 50 EX
tst r6, r6 ! 86 MT
bt/s 98f ! 110 BR
mov.b r1,@-r0 ! 29 LS
! 4 cycles, 2 bytes per iteration
3: mov.b @(r0,r5),r1 ! 20 LS (latency=2)
4: mov.b @(r0,r3),r2 ! 20 LS (latency=2)
dt r6 ! 67 EX
mov.b r1,@-r0 ! 29 LS
bf/s 3b ! 111 BR
mov.b r2,@-r0 ! 29 LS
98:
rts
nop
99: rts
mov r4, r0
! Size is not small, so its worthwhile looking for optimisations.
! First align destination to a long word boundary.
!
! r5 = normal value -1
6: tst #3, r0 ! 87 MT
mov #3, r3 ! 6 EX
bt/s 2f ! 111 BR
and r0,r3 ! 78 EX
! 3 cycles, 1 byte per iteration
1: dt r3 ! 67 EX
mov.b @(r0,r5),r1 ! 19 LS (latency=2)
add #-1, r6 ! 79 EX
bf/s 1b ! 109 BR
mov.b r1,@-r0 ! 28 LS
2: add #1, r5 ! 79 EX
! Now select the appropriate bulk transfer code based on relative
! alignment of src and dst.
mov r0, r3 ! 5 MT (latency=0)
mov r5, r0 ! 5 MT (latency=0)
tst #1, r0 ! 87 MT
bf/s 1f ! 111 BR
mov #64, r7 ! 6 EX
! bit 0 clear
cmp/ge r7, r6 ! 55 MT
bt/s 2f ! 111 BR
tst #2, r0 ! 87 MT
! small
bt/s .Lcase0
mov r3, r0
bra .Lcase2
nop
! big
2: bt/s .Lcase0b
mov r3, r0
bra .Lcase2b
nop
! bit 0 set
1: tst #2, r0 ! 87 MT
bt/s .Lcase1
mov r3, r0
bra .Lcase3
nop
!
! GHIJ KLMN OPQR --> GHIJ KLMN OPQR
!
! src, dst and size are all long word aligned
! size is non-zero
.balign 32
.Lcase00:
mov #64, r1 ! 6 EX
mov r5, r3 ! 5 MT (latency=0)
cmp/gt r6, r1 ! 56 MT
add #-4, r5 ! 50 EX
bf .Lcase00b ! 108 BR (big loop)
shlr2 r6 ! 105 EX
shlr r6 ! 104 EX
mov.l @(r0, r5), r1 ! 21 LS (latency=2)
bf/s 4f ! 111 BR
add #-8, r3 ! 50 EX
tst r6, r6 ! 86 MT
bt/s 5f ! 110 BR
mov.l r1,@-r0 ! 30 LS
! 4 cycles, 2 long words per iteration
3: mov.l @(r0, r5), r1 ! 21 LS (latency=2)
4: mov.l @(r0, r3), r2 ! 21 LS (latency=2)
dt r6 ! 67 EX
mov.l r1, @-r0 ! 30 LS
bf/s 3b ! 109 BR
mov.l r2, @-r0 ! 30 LS
5: rts
nop
! Size is 16 or greater and less than 64, but may have trailing bytes
.balign 32
.Lcase0:
add #-4, r5 ! 50 EX
mov r4, r7 ! 5 MT (latency=0)
mov.l @(r0, r5), r1 ! 21 LS (latency=2)
mov #4, r2 ! 6 EX
add #11, r7 ! 50 EX
tst r2, r6 ! 86 MT
mov r5, r3 ! 5 MT (latency=0)
bt/s 4f ! 111 BR
add #-4, r3 ! 50 EX
mov.l r1,@-r0 ! 30 LS
! 4 cycles, 2 long words per iteration
3: mov.l @(r0, r5), r1 ! 21 LS (latency=2)
4: mov.l @(r0, r3), r2 ! 21 LS (latency=2)
cmp/hi r7, r0
mov.l r1, @-r0 ! 30 LS
bt/s 3b ! 109 BR
mov.l r2, @-r0 ! 30 LS
! Copy the final 0-3 bytes
add #3,r5 ! 50 EX
cmp/eq r0, r4 ! 54 MT
add #-10, r7 ! 50 EX
bt 9f ! 110 BR
! 3 cycles, 1 byte per iteration
1: mov.b @(r0,r5),r1 ! 19 LS
cmp/hi r7,r0 ! 57 MT
bt/s 1b ! 111 BR
mov.b r1,@-r0 ! 28 LS
9: rts
nop
! Size is at least 64 bytes, so will be going round the big loop at least once.
!
! r2 = rounded up r4
! r3 = rounded down r0
.balign 32
.Lcase0b:
add #-4, r5 ! 50 EX
.Lcase00b:
mov r0, r3 ! 5 MT (latency=0)
mov #(~0x1f), r1 ! 6 EX
and r1, r3 ! 78 EX
mov r4, r2 ! 5 MT (latency=0)
cmp/eq r3, r0 ! 54 MT
add #0x1f, r2 ! 50 EX
bt/s 1f ! 110 BR
and r1, r2 ! 78 EX
! copy initial words until cache line aligned
mov.l @(r0, r5), r1 ! 21 LS (latency=2)
tst #4, r0 ! 87 MT
mov r5, r6 ! 5 MT (latency=0)
add #-4, r6 ! 50 EX
bt/s 4f ! 111 BR
add #8, r3 ! 50 EX
tst #0x18, r0 ! 87 MT
bt/s 1f ! 109 BR
mov.l r1,@-r0 ! 30 LS
! 4 cycles, 2 long words per iteration
3: mov.l @(r0, r5), r1 ! 21 LS (latency=2)
4: mov.l @(r0, r6), r7 ! 21 LS (latency=2)
cmp/eq r3, r0 ! 54 MT
mov.l r1, @-r0 ! 30 LS
bf/s 3b ! 109 BR
mov.l r7, @-r0 ! 30 LS
! Copy the cache line aligned blocks
!
! In use: r0, r2, r4, r5
! Scratch: r1, r3, r6, r7
!
! We could do this with the four scratch registers, but if src
! and dest hit the same cache line, this will thrash, so make
! use of additional registers.
!
! We also need r0 as a temporary (for movca), so 'undo' the invariant:
! r5: src (was r0+r5)
! r1: dest (was r0)
! this can be reversed at the end, so we don't need to save any extra
! state.
!
1: mov.l r8, @-r15 ! 30 LS
add r0, r5 ! 49 EX
mov.l r9, @-r15 ! 30 LS
mov r0, r1 ! 5 MT (latency=0)
mov.l r10, @-r15 ! 30 LS
add #-0x1c, r5 ! 50 EX
mov.l r11, @-r15 ! 30 LS
! 16 cycles, 32 bytes per iteration
2: mov.l @(0x00,r5),r0 ! 18 LS (latency=2)
add #-0x20, r1 ! 50 EX
mov.l @(0x04,r5),r3 ! 18 LS (latency=2)
mov.l @(0x08,r5),r6 ! 18 LS (latency=2)
mov.l @(0x0c,r5),r7 ! 18 LS (latency=2)
mov.l @(0x10,r5),r8 ! 18 LS (latency=2)
mov.l @(0x14,r5),r9 ! 18 LS (latency=2)
mov.l @(0x18,r5),r10 ! 18 LS (latency=2)
mov.l @(0x1c,r5),r11 ! 18 LS (latency=2)
movca.l r0,@r1 ! 40 LS (latency=3-7)
mov.l r3,@(0x04,r1) ! 33 LS
mov.l r6,@(0x08,r1) ! 33 LS
mov.l r7,@(0x0c,r1) ! 33 LS
mov.l r8,@(0x10,r1) ! 33 LS
add #-0x20, r5 ! 50 EX
mov.l r9,@(0x14,r1) ! 33 LS
cmp/eq r2,r1 ! 54 MT
mov.l r10,@(0x18,r1) ! 33 LS
bf/s 2b ! 109 BR
mov.l r11,@(0x1c,r1) ! 33 LS
mov r1, r0 ! 5 MT (latency=0)
mov.l @r15+, r11 ! 15 LS
sub r1, r5 ! 75 EX
mov.l @r15+, r10 ! 15 LS
cmp/eq r4, r0 ! 54 MT
bf/s 1f ! 109 BR
mov.l @r15+, r9 ! 15 LS
rts
1: mov.l @r15+, r8 ! 15 LS
sub r4, r1 ! 75 EX (len remaining)
! number of trailing bytes is non-zero
!
! invariants restored (r5 already decremented by 4)
! also r1=num bytes remaining
mov #4, r2 ! 6 EX
mov r4, r7 ! 5 MT (latency=0)
add #0x1c, r5 ! 50 EX (back to -4)
cmp/hs r2, r1 ! 58 MT
bf/s 5f ! 108 BR
add #11, r7 ! 50 EX
mov.l @(r0, r5), r6 ! 21 LS (latency=2)
tst r2, r1 ! 86 MT
mov r5, r3 ! 5 MT (latency=0)
bt/s 4f ! 111 BR
add #-4, r3 ! 50 EX
cmp/hs r2, r1 ! 58 MT
bt/s 5f ! 111 BR
mov.l r6,@-r0 ! 30 LS
! 4 cycles, 2 long words per iteration
3: mov.l @(r0, r5), r6 ! 21 LS (latency=2)
4: mov.l @(r0, r3), r2 ! 21 LS (latency=2)
cmp/hi r7, r0
mov.l r6, @-r0 ! 30 LS
bt/s 3b ! 109 BR
mov.l r2, @-r0 ! 30 LS
! Copy the final 0-3 bytes
5: cmp/eq r0, r4 ! 54 MT
add #-10, r7 ! 50 EX
bt 9f ! 110 BR
add #3,r5 ! 50 EX
! 3 cycles, 1 byte per iteration
1: mov.b @(r0,r5),r1 ! 19 LS
cmp/hi r7,r0 ! 57 MT
bt/s 1b ! 111 BR
mov.b r1,@-r0 ! 28 LS
9: rts
nop
!
! GHIJ KLMN OPQR --> ..GH IJKL MNOP QR..
!
.balign 32
.Lcase2:
! Size is 16 or greater and less then 64, but may have trailing bytes
2: mov r5, r6 ! 5 MT (latency=0)
add #-2,r5 ! 50 EX
mov r4,r2 ! 5 MT (latency=0)
add #-4,r6 ! 50 EX
add #7,r2 ! 50 EX
3: mov.w @(r0,r5),r1 ! 20 LS (latency=2)
mov.w @(r0,r6),r3 ! 20 LS (latency=2)
cmp/hi r2,r0 ! 57 MT
mov.w r1,@-r0 ! 29 LS
bt/s 3b ! 111 BR
mov.w r3,@-r0 ! 29 LS
bra 10f
nop
.balign 32
.Lcase2b:
! Size is at least 64 bytes, so will be going round the big loop at least once.
!
! r2 = rounded up r4
! r3 = rounded down r0
mov r0, r3 ! 5 MT (latency=0)
mov #(~0x1f), r1 ! 6 EX
and r1, r3 ! 78 EX
mov r4, r2 ! 5 MT (latency=0)
cmp/eq r3, r0 ! 54 MT
add #0x1f, r2 ! 50 EX
add #-2, r5 ! 50 EX
bt/s 1f ! 110 BR
and r1, r2 ! 78 EX
! Copy a short word one at a time until we are cache line aligned
! Normal values: r0, r2, r3, r4
! Unused: r1, r6, r7
! Mod: r5 (=r5-2)
!
add #2, r3 ! 50 EX
2: mov.w @(r0,r5),r1 ! 20 LS (latency=2)
cmp/eq r3,r0 ! 54 MT
bf/s 2b ! 111 BR
mov.w r1,@-r0 ! 29 LS
! Copy the cache line aligned blocks
!
! In use: r0, r2, r4, r5 (=r5-2)
! Scratch: r1, r3, r6, r7
!
! We could do this with the four scratch registers, but if src
! and dest hit the same cache line, this will thrash, so make
! use of additional registers.
!
! We also need r0 as a temporary (for movca), so 'undo' the invariant:
! r5: src (was r0+r5)
! r1: dest (was r0)
! this can be reversed at the end, so we don't need to save any extra
! state.
!
1: mov.l r8, @-r15 ! 30 LS
add r0, r5 ! 49 EX
mov.l r9, @-r15 ! 30 LS
mov r0, r1 ! 5 MT (latency=0)
mov.l r10, @-r15 ! 30 LS
add #-0x1e, r5 ! 50 EX
mov.l r11, @-r15 ! 30 LS
mov.l r12, @-r15 ! 30 LS
! 17 cycles, 32 bytes per iteration
#ifdef CONFIG_CPU_LITTLE_ENDIAN
2: mov.w @r5+, r0 ! 14 LS (latency=2) ..JI
add #-0x20, r1 ! 50 EX
mov.l @r5+, r3 ! 15 LS (latency=2) NMLK
mov.l @r5+, r6 ! 15 LS (latency=2) RQPO
shll16 r0 ! 103 EX JI..
mov.l @r5+, r7 ! 15 LS (latency=2)
xtrct r3, r0 ! 48 EX LKJI
mov.l @r5+, r8 ! 15 LS (latency=2)
xtrct r6, r3 ! 48 EX PONM
mov.l @r5+, r9 ! 15 LS (latency=2)
xtrct r7, r6 ! 48 EX
mov.l @r5+, r10 ! 15 LS (latency=2)
xtrct r8, r7 ! 48 EX
mov.l @r5+, r11 ! 15 LS (latency=2)
xtrct r9, r8 ! 48 EX
mov.w @r5+, r12 ! 15 LS (latency=2)
xtrct r10, r9 ! 48 EX
movca.l r0,@r1 ! 40 LS (latency=3-7)
xtrct r11, r10 ! 48 EX
mov.l r3, @(0x04,r1) ! 33 LS
xtrct r12, r11 ! 48 EX
mov.l r6, @(0x08,r1) ! 33 LS
mov.l r7, @(0x0c,r1) ! 33 LS
mov.l r8, @(0x10,r1) ! 33 LS
add #-0x40, r5 ! 50 EX
mov.l r9, @(0x14,r1) ! 33 LS
cmp/eq r2,r1 ! 54 MT
mov.l r10, @(0x18,r1) ! 33 LS
bf/s 2b ! 109 BR
mov.l r11, @(0x1c,r1) ! 33 LS
#else
2: mov.w @(0x1e,r5), r0 ! 17 LS (latency=2)
add #-2, r5 ! 50 EX
mov.l @(0x1c,r5), r3 ! 18 LS (latency=2)
add #-4, r1 ! 50 EX
mov.l @(0x18,r5), r6 ! 18 LS (latency=2)
shll16 r0 ! 103 EX
mov.l @(0x14,r5), r7 ! 18 LS (latency=2)
xtrct r3, r0 ! 48 EX
mov.l @(0x10,r5), r8 ! 18 LS (latency=2)
xtrct r6, r3 ! 48 EX
mov.l @(0x0c,r5), r9 ! 18 LS (latency=2)
xtrct r7, r6 ! 48 EX
mov.l @(0x08,r5), r10 ! 18 LS (latency=2)
xtrct r8, r7 ! 48 EX
mov.l @(0x04,r5), r11 ! 18 LS (latency=2)
xtrct r9, r8 ! 48 EX
mov.l @(0x00,r5), r12 ! 18 LS (latency=2)
xtrct r10, r9 ! 48 EX
movca.l r0,@r1 ! 40 LS (latency=3-7)
add #-0x1c, r1 ! 50 EX
mov.l r3, @(0x18,r1) ! 33 LS
xtrct r11, r10 ! 48 EX
mov.l r6, @(0x14,r1) ! 33 LS
xtrct r12, r11 ! 48 EX
mov.l r7, @(0x10,r1) ! 33 LS
mov.l r8, @(0x0c,r1) ! 33 LS
add #-0x1e, r5 ! 50 EX
mov.l r9, @(0x08,r1) ! 33 LS
cmp/eq r2,r1 ! 54 MT
mov.l r10, @(0x04,r1) ! 33 LS
bf/s 2b ! 109 BR
mov.l r11, @(0x00,r1) ! 33 LS
#endif
mov.l @r15+, r12
mov r1, r0 ! 5 MT (latency=0)
mov.l @r15+, r11 ! 15 LS
sub r1, r5 ! 75 EX
mov.l @r15+, r10 ! 15 LS
cmp/eq r4, r0 ! 54 MT
bf/s 1f ! 109 BR
mov.l @r15+, r9 ! 15 LS
rts
1: mov.l @r15+, r8 ! 15 LS
add #0x1e, r5 ! 50 EX
! Finish off a short word at a time
! r5 must be invariant - 2
10: mov r4,r2 ! 5 MT (latency=0)
add #1,r2 ! 50 EX
cmp/hi r2, r0 ! 57 MT
bf/s 1f ! 109 BR
add #2, r2 ! 50 EX
3: mov.w @(r0,r5),r1 ! 20 LS
cmp/hi r2,r0 ! 57 MT
bt/s 3b ! 109 BR
mov.w r1,@-r0 ! 29 LS
1:
!
! Finally, copy the last byte if necessary
cmp/eq r4,r0 ! 54 MT
bt/s 9b
add #1,r5
mov.b @(r0,r5),r1
rts
mov.b r1,@-r0
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