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| ! SPDX-License-Identifier: GPL-2.0
| !
| ! 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 minimum 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
|
|
