mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 09:44:18 +08:00
218 lines
5.1 KiB
ArmAsm
218 lines
5.1 KiB
ArmAsm
!
|
|
! Fast SH memcpy
|
|
!
|
|
! by Toshiyasu Morita (tm@netcom.com)
|
|
! hacked by J"orn Rernnecke (joern.rennecke@superh.com) ("o for o-umlaut)
|
|
! SH5 code Copyright 2002 SuperH Ltd.
|
|
!
|
|
! Entry: ARG0: destination pointer
|
|
! ARG1: source pointer
|
|
! ARG2: byte count
|
|
!
|
|
! Exit: RESULT: destination pointer
|
|
! any other registers in the range r0-r7: trashed
|
|
!
|
|
! Notes: Usually one wants to do small reads and write a longword, but
|
|
! unfortunately it is difficult in some cases to concatanate bytes
|
|
! into a longword on the SH, so this does a longword read and small
|
|
! writes.
|
|
!
|
|
! This implementation makes two assumptions about how it is called:
|
|
!
|
|
! 1.: If the byte count is nonzero, the address of the last byte to be
|
|
! copied is unsigned greater than the address of the first byte to
|
|
! be copied. This could be easily swapped for a signed comparison,
|
|
! but the algorithm used needs some comparison.
|
|
!
|
|
! 2.: When there are two or three bytes in the last word of an 11-or-more
|
|
! bytes memory chunk to b copied, the rest of the word can be read
|
|
! without side effects.
|
|
! This could be easily changed by increasing the minumum size of
|
|
! a fast memcpy and the amount subtracted from r7 before L_2l_loop be 2,
|
|
! however, this would cost a few extra cyles on average.
|
|
! For SHmedia, the assumption is that any quadword can be read in its
|
|
! enirety if at least one byte is included in the copy.
|
|
|
|
/* Imported into Linux kernel by Richard Curnow. This is used to implement the
|
|
__copy_user function in the general case, so it has to be a distinct
|
|
function from intra-kernel memcpy to allow for exception fix-ups in the
|
|
event that the user pointer is bad somewhere in the copy (e.g. due to
|
|
running off the end of the vma).
|
|
|
|
Note, this algorithm will be slightly wasteful in the case where the source
|
|
and destination pointers are equally aligned, because the stlo/sthi pairs
|
|
could then be merged back into single stores. If there are a lot of cache
|
|
misses, this is probably offset by the stall lengths on the preloads.
|
|
|
|
*/
|
|
|
|
/* NOTE : Prefetches removed and allocos guarded by synco to avoid TAKum03020
|
|
* erratum. The first two prefetches are nop-ed out to avoid upsetting the
|
|
* instruction counts used in the jump address calculation.
|
|
* */
|
|
|
|
.section .text..SHmedia32,"ax"
|
|
.little
|
|
.balign 32
|
|
.global copy_user_memcpy
|
|
.global copy_user_memcpy_end
|
|
copy_user_memcpy:
|
|
|
|
#define LDUAQ(P,O,D0,D1) ldlo.q P,O,D0; ldhi.q P,O+7,D1
|
|
#define STUAQ(P,O,D0,D1) stlo.q P,O,D0; sthi.q P,O+7,D1
|
|
#define LDUAL(P,O,D0,D1) ldlo.l P,O,D0; ldhi.l P,O+3,D1
|
|
#define STUAL(P,O,D0,D1) stlo.l P,O,D0; sthi.l P,O+3,D1
|
|
|
|
nop ! ld.b r3,0,r63 ! TAKum03020
|
|
pta/l Large,tr0
|
|
movi 25,r0
|
|
bgeu/u r4,r0,tr0
|
|
nsb r4,r0
|
|
shlli r0,5,r0
|
|
movi (L1-L0+63*32 + 1) & 0xffff,r1
|
|
sub r1, r0, r0
|
|
L0: ptrel r0,tr0
|
|
add r2,r4,r5
|
|
ptabs r18,tr1
|
|
add r3,r4,r6
|
|
blink tr0,r63
|
|
|
|
/* Rearranged to make cut2 safe */
|
|
.balign 8
|
|
L4_7: /* 4..7 byte memcpy cntd. */
|
|
stlo.l r2, 0, r0
|
|
or r6, r7, r6
|
|
sthi.l r5, -1, r6
|
|
stlo.l r5, -4, r6
|
|
blink tr1,r63
|
|
|
|
.balign 8
|
|
L1: /* 0 byte memcpy */
|
|
nop
|
|
blink tr1,r63
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
|
|
L2_3: /* 2 or 3 byte memcpy cntd. */
|
|
st.b r5,-1,r6
|
|
blink tr1,r63
|
|
|
|
/* 1 byte memcpy */
|
|
ld.b r3,0,r0
|
|
st.b r2,0,r0
|
|
blink tr1,r63
|
|
|
|
L8_15: /* 8..15 byte memcpy cntd. */
|
|
stlo.q r2, 0, r0
|
|
or r6, r7, r6
|
|
sthi.q r5, -1, r6
|
|
stlo.q r5, -8, r6
|
|
blink tr1,r63
|
|
|
|
/* 2 or 3 byte memcpy */
|
|
ld.b r3,0,r0
|
|
nop ! ld.b r2,0,r63 ! TAKum03020
|
|
ld.b r3,1,r1
|
|
st.b r2,0,r0
|
|
pta/l L2_3,tr0
|
|
ld.b r6,-1,r6
|
|
st.b r2,1,r1
|
|
blink tr0, r63
|
|
|
|
/* 4 .. 7 byte memcpy */
|
|
LDUAL (r3, 0, r0, r1)
|
|
pta L4_7, tr0
|
|
ldlo.l r6, -4, r7
|
|
or r0, r1, r0
|
|
sthi.l r2, 3, r0
|
|
ldhi.l r6, -1, r6
|
|
blink tr0, r63
|
|
|
|
/* 8 .. 15 byte memcpy */
|
|
LDUAQ (r3, 0, r0, r1)
|
|
pta L8_15, tr0
|
|
ldlo.q r6, -8, r7
|
|
or r0, r1, r0
|
|
sthi.q r2, 7, r0
|
|
ldhi.q r6, -1, r6
|
|
blink tr0, r63
|
|
|
|
/* 16 .. 24 byte memcpy */
|
|
LDUAQ (r3, 0, r0, r1)
|
|
LDUAQ (r3, 8, r8, r9)
|
|
or r0, r1, r0
|
|
sthi.q r2, 7, r0
|
|
or r8, r9, r8
|
|
sthi.q r2, 15, r8
|
|
ldlo.q r6, -8, r7
|
|
ldhi.q r6, -1, r6
|
|
stlo.q r2, 8, r8
|
|
stlo.q r2, 0, r0
|
|
or r6, r7, r6
|
|
sthi.q r5, -1, r6
|
|
stlo.q r5, -8, r6
|
|
blink tr1,r63
|
|
|
|
Large:
|
|
! ld.b r2, 0, r63 ! TAKum03020
|
|
pta/l Loop_ua, tr1
|
|
ori r3, -8, r7
|
|
sub r2, r7, r22
|
|
sub r3, r2, r6
|
|
add r2, r4, r5
|
|
ldlo.q r3, 0, r0
|
|
addi r5, -16, r5
|
|
movi 64+8, r27 ! could subtract r7 from that.
|
|
stlo.q r2, 0, r0
|
|
sthi.q r2, 7, r0
|
|
ldx.q r22, r6, r0
|
|
bgtu/l r27, r4, tr1
|
|
|
|
addi r5, -48, r27
|
|
pta/l Loop_line, tr0
|
|
addi r6, 64, r36
|
|
addi r6, -24, r19
|
|
addi r6, -16, r20
|
|
addi r6, -8, r21
|
|
|
|
Loop_line:
|
|
! ldx.q r22, r36, r63 ! TAKum03020
|
|
alloco r22, 32
|
|
synco
|
|
addi r22, 32, r22
|
|
ldx.q r22, r19, r23
|
|
sthi.q r22, -25, r0
|
|
ldx.q r22, r20, r24
|
|
ldx.q r22, r21, r25
|
|
stlo.q r22, -32, r0
|
|
ldx.q r22, r6, r0
|
|
sthi.q r22, -17, r23
|
|
sthi.q r22, -9, r24
|
|
sthi.q r22, -1, r25
|
|
stlo.q r22, -24, r23
|
|
stlo.q r22, -16, r24
|
|
stlo.q r22, -8, r25
|
|
bgeu r27, r22, tr0
|
|
|
|
Loop_ua:
|
|
addi r22, 8, r22
|
|
sthi.q r22, -1, r0
|
|
stlo.q r22, -8, r0
|
|
ldx.q r22, r6, r0
|
|
bgtu/l r5, r22, tr1
|
|
|
|
add r3, r4, r7
|
|
ldlo.q r7, -8, r1
|
|
sthi.q r22, 7, r0
|
|
ldhi.q r7, -1, r7
|
|
ptabs r18,tr1
|
|
stlo.q r22, 0, r0
|
|
or r1, r7, r1
|
|
sthi.q r5, 15, r1
|
|
stlo.q r5, 8, r1
|
|
blink tr1, r63
|
|
copy_user_memcpy_end:
|
|
nop
|