/* * M7memcpy: Optimized SPARC M7 memcpy * * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
*/
.file"M7memcpy.S"
/* * memcpy(s1, s2, len) * * Copy s2 to s1, always copy n bytes. * Note: this C code does not work for overlapped copies. * * Fast assembler language version of the following C-program for memcpy * which represents the `standard' for the C-library. * * void * * memcpy(void *s, const void *s0, size_t n) * { * if (n != 0) { * char *s1 = s; * const char *s2 = s0; * do { * *s1++ = *s2++; * } while (--n != 0); * } * return (s); * } * * * SPARC T7/M7 Flow : * * if (count < SMALL_MAX) { * if count < SHORTCOPY (SHORTCOPY=3) * copy bytes; exit with dst addr * if src & dst aligned on word boundary but not long word boundary, * copy with ldw/stw; branch to finish_up * if src & dst aligned on long word boundary * copy with ldx/stx; branch to finish_up * if src & dst not aligned and length <= SHORTCHECK (SHORTCHECK=14) * copy bytes; exit with dst addr * move enough bytes to get src to word boundary * if dst now on word boundary * move_words: * copy words; branch to finish_up * if dst now on half word boundary * load words, shift half words, store words; branch to finish_up * if dst on byte 1 * load words, shift 3 bytes, store words; branch to finish_up * if dst on byte 3 * load words, shift 1 byte, store words; branch to finish_up * finish_up: * copy bytes; exit with dst addr * } else { More than SMALL_MAX bytes * move bytes until dst is on long word boundary * if( src is on long word boundary ) { * if (count < MED_MAX) { * finish_long: src/dst aligned on 8 bytes * copy with ldx/stx in 8-way unrolled loop; * copy final 0-63 bytes; exit with dst addr * } else { src/dst aligned; count > MED_MAX * align dst on 64 byte boundary; for main data movement: * prefetch src data to L2 cache; let HW prefetch move data to L1 cache * Use BIS (block initializing store) to avoid copying store cache * lines from memory. But pre-store first element of each cache line * ST_CHUNK lines in advance of the rest of that cache line. That * gives time for replacement cache lines to be written back without * excess STQ and Miss Buffer filling. Repeat until near the end, * then finish up storing before going to finish_long. * } * } else { src/dst not aligned on 8 bytes * if src is word aligned and count < MED_WMAX * move words in 8-way unrolled loop * move final 0-31 bytes; exit with dst addr * if count < MED_UMAX * use alignaddr/faligndata combined with ldd/std in 8-way * unrolled loop to move data. * go to unalign_done * else * setup alignaddr for faligndata instructions * align dst on 64 byte boundary; prefetch src data to L1 cache * loadx8, falign, block-store, prefetch loop * (only use block-init-store when src/dst on 8 byte boundaries.) * unalign_done: * move remaining bytes for unaligned cases. exit with dst addr. * } *
*/
#ifndef EX_LD
#define EX_LD(x,y) x
#endif
#ifndef EX_LD_FP
#define EX_LD_FP(x,y) x
#endif
#ifndef EX_ST
#define EX_ST(x,y) x
#endif
#ifndef EX_ST_FP
#define EX_ST_FP(x,y) x
#endif
#ifndef EX_RETVAL
#define EX_RETVAL(x) x
#endif
#ifndef LOAD
#define LOAD(type,addr,dest) type [addr], dest
#endif
#ifndef STORE
#define STORE(type,src,addr) type src, [addr]
#endif
/* * ASI_BLK_INIT_QUAD_LDD_P/ASI_BLK_INIT_QUAD_LDD_S marks the cache * line as "least recently used" which means if many threads are * active, it has a high probability of being pushed out of the cache * between the first initializing store and the final stores. * Thus, we use ASI_ST_BLKINIT_MRU_P/ASI_ST_BLKINIT_MRU_S which * marks the cache line as "most recently used" for all * but the last cache line
*/
#ifndef STORE_ASI
#ifndef SIMULATE_NIAGARA_ON_NON_NIAGARA
#define STORE_ASI ASI_BLK_INIT_QUAD_LDD_P
#else
#define STORE_ASI 0x80 /* ASI_P */
#endif
#endif
#define BLOCK_SIZE 64
#define SHORTCOPY 3
#define SHORTCHECK 14
#define SHORT_LONG 64 /* max copy for short longword-aligned case */ /* must be at least 64 */
#define SMALL_MAX 128
#define MED_UMAX 1024 /* max copy for medium un-aligned case */
#define MED_WMAX 1024 /* max copy for medium word-aligned case */
#define MED_MAX 1024 /* max copy for medium longword-aligned case */
#define ST_CHUNK 24 /* ST_CHUNK - block of values for BIS Store */
#define ALIGN_PRE 24 /* distance for aligned prefetch loop */
! %o5 has the bytes to be written in partial store. sub %o2, %o5, %o2 sub %o1, %o0, %o1 ! %o1 gets the difference
7: ! dst aligning loop
add %o1, %o0, %o4
EX_LD(LOAD(ldub, %o4, %o4), memcpy_retl_o2_plus_o5) ! load one byte
subcc %o5, 1, %o5
EX_ST(STORE(stb, %o4, %o0), memcpy_retl_o2_plus_o5_plus_1)
bgu,pt %xcc, 7b
add %o0, 1, %o0 ! advance dst
add %o1, %o0, %o1 ! restore %o1
.Ldst_aligned_on_8:
andcc %o1, 7, %o5
brnz,pt %o5, .Lsrc_dst_unaligned_on_8
nop
.Lsrc_dst_aligned_on_8: ! check if we are copying MED_MAX or more bytes set MED_MAX, %o3
cmp %o2, %o3 ! limit to store buffer size
bgu,pn %xcc, .Llarge_align8_copy
nop
/* * Special case for handling when src and dest are both long word aligned * and total data to move is less than MED_MAX bytes
*/
.Lmedlong:
subcc %o2, 63, %o2 ! adjust length to allow cc test
ble,pn %xcc, .Lmedl63 ! skip big loop if less than 64 bytes
nop
.Lmedl64:
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2_plus_63) ! load
subcc %o2, 64, %o2 ! decrement length count
EX_ST(STORE(stx, %o4, %o0), memcpy_retl_o2_plus_63_64) ! and store
EX_LD(LOAD(ldx, %o1+8, %o3), memcpy_retl_o2_plus_63_56) ! a block of 64
EX_ST(STORE(stx, %o3, %o0+8), memcpy_retl_o2_plus_63_56)
EX_LD(LOAD(ldx, %o1+16, %o4), memcpy_retl_o2_plus_63_48)
EX_ST(STORE(stx, %o4, %o0+16), memcpy_retl_o2_plus_63_48)
EX_LD(LOAD(ldx, %o1+24, %o3), memcpy_retl_o2_plus_63_40)
EX_ST(STORE(stx, %o3, %o0+24), memcpy_retl_o2_plus_63_40)
EX_LD(LOAD(ldx, %o1+32, %o4), memcpy_retl_o2_plus_63_32)! load and store
EX_ST(STORE(stx, %o4, %o0+32), memcpy_retl_o2_plus_63_32)
EX_LD(LOAD(ldx, %o1+40, %o3), memcpy_retl_o2_plus_63_24)! a block of 64
add %o1, 64, %o1 ! increase src ptr by 64
EX_ST(STORE(stx, %o3, %o0+40), memcpy_retl_o2_plus_63_24)
EX_LD(LOAD(ldx, %o1-16, %o4), memcpy_retl_o2_plus_63_16)
add %o0, 64, %o0 ! increase dst ptr by 64
EX_ST(STORE(stx, %o4, %o0-16), memcpy_retl_o2_plus_63_16)
EX_LD(LOAD(ldx, %o1-8, %o3), memcpy_retl_o2_plus_63_8)
bgu,pt %xcc, .Lmedl64 ! repeat if at least 64 bytes left
EX_ST(STORE(stx, %o3, %o0-8), memcpy_retl_o2_plus_63_8)
.Lmedl63:
addcc %o2, 32, %o2 ! adjust remaining count
ble,pt %xcc, .Lmedl31 ! to skip if 31 or fewer bytes left
nop
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2_plus_31) ! load sub %o2, 32, %o2 ! decrement length count
EX_ST(STORE(stx, %o4, %o0), memcpy_retl_o2_plus_31_32) ! and store
EX_LD(LOAD(ldx, %o1+8, %o3), memcpy_retl_o2_plus_31_24) ! a block of 32
add %o1, 32, %o1 ! increase src ptr by 32
EX_ST(STORE(stx, %o3, %o0+8), memcpy_retl_o2_plus_31_24)
EX_LD(LOAD(ldx, %o1-16, %o4), memcpy_retl_o2_plus_31_16)
add %o0, 32, %o0 ! increase dst ptr by 32
EX_ST(STORE(stx, %o4, %o0-16), memcpy_retl_o2_plus_31_16)
EX_LD(LOAD(ldx, %o1-8, %o3), memcpy_retl_o2_plus_31_8)
EX_ST(STORE(stx, %o3, %o0-8), memcpy_retl_o2_plus_31_8)
.Lmedl31:
addcc %o2, 16, %o2 ! adjust remaining count
ble,pt %xcc, .Lmedl15 ! skip if 15 or fewer bytes left
nop !
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2_plus_15)
add %o1, 16, %o1 ! increase src ptr by 16
EX_ST(STORE(stx, %o4, %o0), memcpy_retl_o2_plus_15) sub %o2, 16, %o2 ! decrease count by 16
EX_LD(LOAD(ldx, %o1-8, %o3), memcpy_retl_o2_plus_15_8)
add %o0, 16, %o0 ! increase dst ptr by 16
EX_ST(STORE(stx, %o3, %o0-8), memcpy_retl_o2_plus_15_8)
.Lmedl15:
addcc %o2, 15, %o2 ! restore count
bz,pt %xcc, .Lsmallx ! exit if finished
cmp %o2, 8
blt,pt %xcc, .Lmedw7 ! skip if 7 or fewer bytes left
tst %o2
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2) ! load 8 bytes
add %o1, 8, %o1 ! increase src ptr by 8
add %o0, 8, %o0 ! increase dst ptr by 8
subcc %o2, 8, %o2 ! decrease count by 8
bnz,pn %xcc, .Lmedw7
EX_ST(STORE(stx, %o4, %o0-8), memcpy_retl_o2_plus_8) ! and store 8
retl
mov EX_RETVAL(%g1), %o0 ! restore %o0
.align 16
.Lsrc_dst_unaligned_on_8: ! DST is 8-byte aligned, src is not
2:
andcc %o1, 0x3, %o5 ! test word alignment
bnz,pt %xcc, .Lunalignsetup ! branch to skip if not word aligned
nop
/* * Handle all cases where src and dest are aligned on word * boundaries. Use unrolled loops for better performance. * This option wins over standard large data move when * source and destination is in cache for.Lmedium * to short data moves.
*/ set MED_WMAX, %o3
cmp %o2, %o3 ! limit to store buffer size
bge,pt %xcc, .Lunalignrejoin ! otherwise rejoin main loop
nop
subcc %o2, 31, %o2 ! adjust length to allow cc test ! for end of loop
ble,pt %xcc, .Lmedw31 ! skip big loop if less than 16
.Lmedw32:
EX_LD(LOAD(ld, %o1, %o4), memcpy_retl_o2_plus_31)! move a block of 32 sllx %o4, 32, %o5
EX_LD(LOAD(ld, %o1+4, %o4), memcpy_retl_o2_plus_31)
or %o4, %o5, %o5
EX_ST(STORE(stx, %o5, %o0), memcpy_retl_o2_plus_31)
subcc %o2, 32, %o2 ! decrement length count
EX_LD(LOAD(ld, %o1+8, %o4), memcpy_retl_o2_plus_31_24) sllx %o4, 32, %o5
EX_LD(LOAD(ld, %o1+12, %o4), memcpy_retl_o2_plus_31_24)
or %o4, %o5, %o5
EX_ST(STORE(stx, %o5, %o0+8), memcpy_retl_o2_plus_31_24)
add %o1, 32, %o1 ! increase src ptr by 32
EX_LD(LOAD(ld, %o1-16, %o4), memcpy_retl_o2_plus_31_16) sllx %o4, 32, %o5
EX_LD(LOAD(ld, %o1-12, %o4), memcpy_retl_o2_plus_31_16)
or %o4, %o5, %o5
EX_ST(STORE(stx, %o5, %o0+16), memcpy_retl_o2_plus_31_16)
add %o0, 32, %o0 ! increase dst ptr by 32
EX_LD(LOAD(ld, %o1-8, %o4), memcpy_retl_o2_plus_31_8) sllx %o4, 32, %o5
EX_LD(LOAD(ld, %o1-4, %o4), memcpy_retl_o2_plus_31_8)
or %o4, %o5, %o5
bgu,pt %xcc, .Lmedw32 ! repeat if at least 32 bytes left
EX_ST(STORE(stx, %o5, %o0-8), memcpy_retl_o2_plus_31_8)
.Lmedw31:
addcc %o2, 31, %o2 ! restore count
bz,pt %xcc, .Lsmallx ! exit if finished
nop
cmp %o2, 16
blt,pt %xcc, .Lmedw15
nop
EX_LD(LOAD(ld, %o1, %o4), memcpy_retl_o2)! move a block of 16 bytes sllx %o4, 32, %o5
subcc %o2, 16, %o2 ! decrement length count
EX_LD(LOAD(ld, %o1+4, %o4), memcpy_retl_o2_plus_16)
or %o4, %o5, %o5
EX_ST(STORE(stx, %o5, %o0), memcpy_retl_o2_plus_16)
add %o1, 16, %o1 ! increase src ptr by 16
EX_LD(LOAD(ld, %o1-8, %o4), memcpy_retl_o2_plus_8)
add %o0, 16, %o0 ! increase dst ptr by 16 sllx %o4, 32, %o5
EX_LD(LOAD(ld, %o1-4, %o4), memcpy_retl_o2_plus_8)
or %o4, %o5, %o5
EX_ST(STORE(stx, %o5, %o0-8), memcpy_retl_o2_plus_8)
.Lmedw15:
bz,pt %xcc, .Lsmallx ! exit if finished
cmp %o2, 8
blt,pn %xcc, .Lmedw7 ! skip if 7 or fewer bytes left
tst %o2
EX_LD(LOAD(ld, %o1, %o4), memcpy_retl_o2) ! load 4 bytes
subcc %o2, 8, %o2 ! decrease count by 8
EX_ST(STORE(stw, %o4, %o0), memcpy_retl_o2_plus_8)! and store 4 bytes
add %o1, 8, %o1 ! increase src ptr by 8
EX_LD(LOAD(ld, %o1-4, %o3), memcpy_retl_o2_plus_4) ! load 4 bytes
add %o0, 8, %o0 ! increase dst ptr by 8
EX_ST(STORE(stw, %o3, %o0-4), memcpy_retl_o2_plus_4)! and store 4 bytes
bz,pt %xcc, .Lsmallx ! exit if finished
.Lmedw7: ! count is ge 1, less than 8
cmp %o2, 4 ! check for 4 bytes left
blt,pn %xcc, .Lsmallleft3 ! skip if 3 or fewer bytes left
nop !
EX_LD(LOAD(ld, %o1, %o4), memcpy_retl_o2) ! load 4 bytes
add %o1, 4, %o1 ! increase src ptr by 4
add %o0, 4, %o0 ! increase dst ptr by 4
subcc %o2, 4, %o2 ! decrease count by 4
bnz .Lsmallleft3
EX_ST(STORE(stw, %o4, %o0-4), memcpy_retl_o2_plus_4)! and store 4 bytes
retl
mov EX_RETVAL(%g1), %o0
.align 16
.Llarge_align8_copy: ! Src and dst share 8 byte alignment ! align dst to 64 byte boundary
andcc %o0, 0x3f, %o3 ! %o3 == 0 means dst is 64 byte aligned
brz,pn %o3, .Laligned_to_64
andcc %o0, 8, %o3 ! odd long words to move?
brz,pt %o3, .Laligned_to_16
nop
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2) sub %o2, 8, %o2
add %o1, 8, %o1 ! increment src ptr
add %o0, 8, %o0 ! increment dst ptr
EX_ST(STORE(stx, %o4, %o0-8), memcpy_retl_o2_plus_8)
.Laligned_to_16:
andcc %o0, 16, %o3 ! pair of long words to move?
brz,pt %o3, .Laligned_to_32
nop
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2) sub %o2, 16, %o2
EX_ST(STORE(stx, %o4, %o0), memcpy_retl_o2_plus_16)
add %o1, 16, %o1 ! increment src ptr
EX_LD(LOAD(ldx, %o1-8, %o4), memcpy_retl_o2_plus_8)
add %o0, 16, %o0 ! increment dst ptr
EX_ST(STORE(stx, %o4, %o0-8), memcpy_retl_o2_plus_8)
.Laligned_to_32:
andcc %o0, 32, %o3 ! four long words to move?
brz,pt %o3, .Laligned_to_64
nop
EX_LD(LOAD(ldx, %o1, %o4), memcpy_retl_o2) sub %o2, 32, %o2
EX_ST(STORE(stx, %o4, %o0), memcpy_retl_o2_plus_32)
EX_LD(LOAD(ldx, %o1+8, %o4), memcpy_retl_o2_plus_24)
EX_ST(STORE(stx, %o4, %o0+8), memcpy_retl_o2_plus_24)
EX_LD(LOAD(ldx, %o1+16, %o4), memcpy_retl_o2_plus_16)
EX_ST(STORE(stx, %o4, %o0+16), memcpy_retl_o2_plus_16)
add %o1, 32, %o1 ! increment src ptr
EX_LD(LOAD(ldx, %o1-8, %o4), memcpy_retl_o2_plus_8)
add %o0, 32, %o0 ! increment dst ptr
EX_ST(STORE(stx, %o4, %o0-8), memcpy_retl_o2_plus_8)
.Laligned_to_64: ! ! Using block init store (BIS) instructions to avoid fetching cache ! lines from memory. Use ST_CHUNK stores to first element of each cache ! line (similar to prefetching) to avoid overfilling STQ or miss buffers. ! Gives existing cache lines time to be moved out of L1/L2/L3 cache. ! Initial stores using MRU version of BIS to keep cache line in ! cache until we are ready to store final element of cache line. ! Then store last element using the LRU version of BIS. !
andn %o2, 0x3f, %o5 ! %o5 is multiple of block size
and %o2, 0x3f, %o2 ! residue bytes in %o2 ! ! We use STORE_MRU_ASI for the first seven stores to each cache line ! followed by STORE_ASI (mark as LRU) for the last store. That ! mixed approach reduces the probability that the cache line is removed ! before we finish setting it, while minimizing the effects on ! other cached values during a large memcpy ! ! ST_CHUNK batches up initial BIS operations for several cache lines ! to allow multiple requests to not be blocked by overflowing the ! the store miss buffer. Then the matching stores for all those ! BIS operations are executed. !
.Lalign_done:
add %o0, 8, %o0 ! restore %o0 from ASI alignment
membar #StoreStore sub %o2, 63, %o2 ! adjust length to allow cc test
ba .Lmedl63 ! in .Lmedl63
nop
.align 16 ! Dst is on 8 byte boundary; src is not; remaining count > SMALL_MAX
.Lunalignsetup:
.Lunalignrejoin:
mov %g1, %o3 ! save %g1 as VISEntryHalf clobbers it
#ifdef NON_USER_COPY
VISEntryHalfFast(.Lmedium_vis_entry_fail_cp)
#else
VISEntryHalf
#endif
mov %o3, %g1 ! restore %g1
! Destination is now block (64 byte aligned)
.Lunalignsrc:
andn %o2, 0x3f, %o5 ! %o5 is multiple of block size
and %o2, 0x3f, %o2 ! residue bytes in %o2
add %o2, 64, %o2 ! Insure we do not load beyond sub %o5, 64, %o5 ! end of source buffer
andn %o1, 0x7, %o4 ! %o4 has long word aligned src address
alignaddr %o1, %g0, %g0 ! generate %gsr
add %o1, %o5, %o1 ! advance %o1 to after blocks
.Lunalign_done: ! Handle trailing bytes, 64 to 127 ! Dest long word aligned, Src not long word aligned
cmp %o2, 15
bleu %xcc, .Lunalign_short
andn %o2, 0x7, %o5 ! %o5 is multiple of 8
and %o2, 0x7, %o2 ! residue bytes in %o2
add %o2, 8, %o2 sub %o5, 8, %o5 ! insure we do not load past end of src
andn %o1, 0x7, %o4 ! %o4 has long word aligned src address
add %o1, %o5, %o1 ! advance %o1 to after multiple of 8
EX_LD_FP(LOAD(ldd, %o4, %f0), memcpy_retl_o2_plus_o5)! fetch partialword
.Lunalign_by8:
EX_LD_FP(LOAD(ldd, %o4+8, %f2), memcpy_retl_o2_plus_o5)
add %o4, 8, %o4
faligndata %f0, %f2, %f16
subcc %o5, 8, %o5
EX_ST_FP(STORE(std, %f16, %o0), memcpy_retl_o2_plus_o5_plus_8)
fsrc2 %f2, %f0
bgu,pt %xcc, .Lunalign_by8
add %o0, 8, %o0
.Lunalign_short:
#ifdef NON_USER_COPY
VISExitHalfFast
#else
VISExitHalf
#endif
ba .Lsmallrest
nop
/* * This is a special case of nested memcpy. This can happen when kernel * calls unaligned memcpy back to back without saving FP registers. We need * traps(context switch) to save/restore FP registers. If the kernel calls * memcpy without this trap sequence we will hit FP corruption. Let's use * the normal integer load/store method in this case.
*/
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