diff options
Diffstat (limited to 'arch/sh/lib64/copy_user_memcpy.S')
| -rw-r--r-- | arch/sh/lib64/copy_user_memcpy.S | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/arch/sh/lib64/copy_user_memcpy.S b/arch/sh/lib64/copy_user_memcpy.S new file mode 100644 index 0000000..2a62816 --- /dev/null +++ b/arch/sh/lib64/copy_user_memcpy.S @@ -0,0 +1,217 @@ +! +! 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 |
