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/* $Id: U3memcpy.S,v 1.1.1.1 2004-04-15 01:33:48 phoenix Exp $
 * U3memcpy.S: UltraSparc-III optimized memcpy.
 *
 * Copyright (C) 1999, 2000 David S. Miller (davem@redhat.com)
 */

#ifdef __KERNEL__
#include <asm/visasm.h>
#include <asm/asi.h>
#include <asm/dcu.h>
#include <asm/spitfire.h>
#undef SMALL_COPY_USES_FPU
#else
#define ASI_BLK_P 0xf0
#define FPRS_FEF  0x04
#define VISEntryHalf rd %fprs, %o5; wr %g0, FPRS_FEF, %fprs
#define VISExitHalf and %o5, FPRS_FEF, %o5; wr %o5, 0x0, %fprs
#define SMALL_COPY_USES_FPU
#endif

        /* Special/non-trivial issues of this code:
         *
         * 1) %o5 is preserved from VISEntryHalf to VISExitHalf
         * 2) Only low 32 FPU registers are used so that only the
         *    lower half of the FPU register set is dirtied by this
         *    code.  This is especially important in the kernel.
         * 3) This code never prefetches cachelines past the end
         *    of the source buffer.
         */

        .text
        .align  32

        /* The cheetah's flexible spine, oversized liver, enlarged heart,
         * slender muscular body, and claws make it the swiftest hunter
         * in Africa and the fastest animal on land.  Can reach speeds
         * of up to 2.4GB per second.
         */

        .globl          U3memcpy
U3memcpy: /* %o0=dst, %o1=src, %o2=len */
#ifndef __KERNEL__
        /* Save away original 'dst' for memcpy return value. */
        mov             %o0, %g3                        ! A0    Group
#endif
        /* Anything to copy at all? */
        cmp             %o2, 0                          ! A1
        ble,pn          %icc, U3memcpy_short_ret        ! BR

        /* Extremely small copy? */
         cmp            %o2, 31                         ! A0    Group
        ble,pn          %icc, U3memcpy_short            ! BR

        /* Large enough to use unrolled prefetch loops? */
         cmp            %o2, 0x100                      ! A1
        bge,a,pt        %icc, U3memcpy_enter            ! BR    Group
         andcc          %o0, 0x3f, %g2                  ! A0

        ba,pt           %xcc, U3memcpy_toosmall         ! BR    Group
         andcc          %o0, 0x7, %g2                   ! A0

        .align          32
U3memcpy_short:
        /* Copy %o2 bytes from src to dst, one byte at a time. */
        ldub            [%o1 + 0x00], %o3               ! MS    Group
        add             %o1, 0x1, %o1                   ! A0
        add             %o0, 0x1, %o0                   ! A1
        subcc           %o2, 1, %o2                     ! A0    Group

        bg,pt           %icc, U3memcpy_short            ! BR
         stb            %o3, [%o0 + -1]                 ! MS    Group (1-cycle stall)

U3memcpy_short_ret:
#ifdef __KERNEL__
        retl                                            ! BR    Group (0-4 cycle stall)
         clr            %o0                             ! A0
#else
        retl                                            ! BR    Group (0-4 cycle stall)
         mov            %g3, %o0                        ! A0
#endif

        /* Here len >= (6 * 64) and condition codes reflect execution
         * of "andcc %o0, 0x7, %g2", done by caller.
         */
        .align          64
U3memcpy_enter:
        /* Is 'dst' already aligned on an 64-byte boundary? */
        be,pt           %xcc, 2f                        ! BR

        /* Compute abs((dst & 0x3f) - 0x40) into %g2.  This is the number
         * of bytes to copy to make 'dst' 64-byte aligned.  We pre-
         * subtract this from 'len'.
         */
         sub            %g2, 0x40, %g2                  ! A0    Group
        sub             %g0, %g2, %g2                   ! A0    Group
        sub             %o2, %g2, %o2                   ! A0    Group

        /* Copy %g2 bytes from src to dst, one byte at a time. */
1:      ldub            [%o1 + 0x00], %o3               ! MS    (Group)
        add             %o1, 0x1, %o1                   ! A1
        add             %o0, 0x1, %o0                   ! A0    Group
        subcc           %g2, 0x1, %g2                   ! A1

        bg,pt           %icc, 1b                        ! BR    Group
         stb            %o3, [%o0 + -1]                 ! MS    Group

2:      VISEntryHalf                                    ! MS+MS
        and             %o1, 0x7, %g1                   ! A1
        ba,pt           %xcc, U3memcpy_begin            ! BR
         alignaddr      %o1, %g0, %o1                   ! MS          (Break-after)

        .align          64
U3memcpy_begin:
#ifdef __KERNEL__
        .globl          U3memcpy_nop_1_6
U3memcpy_nop_1_6:
        ldxa            [%g0] ASI_DCU_CONTROL_REG, %g3
        sethi           %uhi(DCU_PE), %o3
        sllx            %o3, 32, %o3
        or              %g3, %o3, %o3
        stxa            %o3, [%g0] ASI_DCU_CONTROL_REG  ! Enable P-cache
        membar          #Sync
#endif
        prefetch        [%o1 + 0x000], #one_read        ! MS    Group1
        prefetch        [%o1 + 0x040], #one_read        ! MS    Group2
        andn            %o2, (0x40 - 1), %o4            ! A0
        prefetch        [%o1 + 0x080], #one_read        ! MS    Group3
        cmp             %o4, 0x140                      ! A0
        prefetch        [%o1 + 0x0c0], #one_read        ! MS    Group4
        ldd             [%o1 + 0x000], %f0              ! MS    Group5 (%f0 results at G8)
        bge,a,pt        %icc, 1f                        ! BR

         prefetch       [%o1 + 0x100], #one_read        ! MS    Group6
1:      ldd             [%o1 + 0x008], %f2              ! AX           (%f2 results at G9)
        cmp             %o4, 0x180                      ! A1
        bge,a,pt        %icc, 1f                        ! BR
         prefetch       [%o1 + 0x140], #one_read        ! MS    Group7
1:      ldd             [%o1 + 0x010], %f4              ! AX           (%f4 results at G10)
        cmp             %o4, 0x1c0                      ! A1
        bge,a,pt        %icc, 1f                        ! BR

         prefetch       [%o1 + 0x180], #one_read        ! MS    Group8
1:      faligndata      %f0, %f2, %f16                  ! FGA   Group9 (%f16 at G12)
        ldd             [%o1 + 0x018], %f6              ! AX           (%f6 results at G12)
        faligndata      %f2, %f4, %f18                  ! FGA   Group10 (%f18 results at G13)
        ldd             [%o1 + 0x020], %f8              ! MS            (%f8 results at G13)
        faligndata      %f4, %f6, %f20                  ! FGA   Group12 (1-cycle stall,%f20 at G15)
        ldd             [%o1 + 0x028], %f10             ! MS            (%f10 results at G15)
        faligndata      %f6, %f8, %f22                  ! FGA   Group13 (%f22 results at G16)

        ldd             [%o1 + 0x030], %f12             ! MS            (%f12 results at G16)
        faligndata      %f8, %f10, %f24                 ! FGA   Group15 (1-cycle stall,%f24 at G18)
        ldd             [%o1 + 0x038], %f14             ! MS            (%f14 results at G18)
        faligndata      %f10, %f12, %f26                ! FGA   Group16 (%f26 results at G19)
        ldd             [%o1 + 0x040], %f0              ! MS            (%f0 results at G19)

        /* We only use the first loop if len > (7 * 64). */
        subcc           %o4, 0x1c0, %o4                 ! A0    Group17
        bg,pt           %icc, U3memcpy_loop1            ! BR
         add            %o1, 0x40, %o1                  ! A1

        add             %o4, 0x140, %o4                 ! A0    Group18
        ba,pt           %xcc, U3memcpy_loop2            ! BR
         srl            %o4, 6, %o3                     ! A0    Group19
        nop
        nop
        nop
        nop
        nop

        nop
        nop

        /* This loop performs the copy and queues new prefetches.
         * We drop into the second loop when len <= (5 * 64).  Note
         * that this (5 * 64) factor has been subtracted from len
         * already.
         */
U3memcpy_loop1:
        ldd             [%o1 + 0x008], %f2              ! MS    Group2  (%f2 results at G5)
        faligndata      %f12, %f14, %f28                ! FGA           (%f28 results at G5)
        ldd             [%o1 + 0x010], %f4              ! MS    Group3  (%f4 results at G6)
        faligndata      %f14, %f0, %f30                 ! FGA   Group4  (1-cycle stall, %f30 at G7)
        stda            %f16, [%o0] ASI_BLK_P           ! MS
        ldd             [%o1 + 0x018], %f6              ! AX            (%f6 results at G7)

        faligndata      %f0, %f2, %f16                  ! FGA   Group12 (7-cycle stall)
        ldd             [%o1 + 0x020], %f8              ! MS            (%f8 results at G15)
        faligndata      %f2, %f4, %f18                  ! FGA   Group13 (%f18 results at G16)
        ldd             [%o1 + 0x028], %f10             ! MS            (%f10 results at G16)
        faligndata      %f4, %f6, %f20                  ! FGA   Group14 (%f20 results at G17)
        ldd             [%o1 + 0x030], %f12             ! MS            (%f12 results at G17)
        faligndata      %f6, %f8, %f22                  ! FGA   Group15 (%f22 results at G18)
        ldd             [%o1 + 0x038], %f14             ! MS            (%f14 results at G18)

        faligndata      %f8, %f10, %f24                 ! FGA   Group16 (%f24 results at G19)
        ldd             [%o1 + 0x040], %f0              ! AX            (%f0 results at G19)
        prefetch        [%o1 + 0x180], #one_read        ! MS
        faligndata      %f10, %f12, %f26                ! FGA   Group17 (%f26 results at G20)
        subcc           %o4, 0x40, %o4                  ! A0
        add             %o1, 0x40, %o1                  ! A1
        bg,pt           %xcc, U3memcpy_loop1            ! BR
         add            %o0, 0x40, %o0                  ! A0    Group18

U3memcpy_loop2_enter:
        mov             5, %o3                          ! A1

        /* This loop performs on the copy, no new prefetches are
         * queued.  We do things this way so that we do not perform
         * any spurious prefetches past the end of the src buffer.
         */
U3memcpy_loop2:
        ldd             [%o1 + 0x008], %f2              ! MS
        faligndata      %f12, %f14, %f28                ! FGA   Group2
        ldd             [%o1 + 0x010], %f4              ! MS
        faligndata      %f14, %f0, %f30                 ! FGA   Group4  (1-cycle stall)
        stda            %f16, [%o0] ASI_BLK_P           ! MS
        ldd             [%o1 + 0x018], %f6              ! AX
        faligndata      %f0, %f2, %f16                  ! FGA   Group12 (7-cycle stall)

        ldd             [%o1 + 0x020], %f8              ! MS
        faligndata      %f2, %f4, %f18                  ! FGA   Group13
        ldd             [%o1 + 0x028], %f10             ! MS
        faligndata      %f4, %f6, %f20                  ! FGA   Group14
        ldd             [%o1 + 0x030], %f12             ! MS
        faligndata      %f6, %f8, %f22                  ! FGA   Group15
        ldd             [%o1 + 0x038], %f14             ! MS
        faligndata      %f8, %f10, %f24                 ! FGA   Group16

        ldd             [%o1 + 0x040], %f0              ! AX
        faligndata      %f10, %f12, %f26                ! FGA   Group17
        subcc           %o3, 0x01, %o3                  ! A0
        add             %o1, 0x40, %o1                  ! A1
        bg,pt           %xcc, U3memcpy_loop2            ! BR
         add            %o0, 0x40, %o0                  ! A0    Group18

        /* Finally we copy the last full 64-byte block. */
U3memcpy_loopfini:
        ldd             [%o1 + 0x008], %f2              ! MS
        faligndata      %f12, %f14, %f28                ! FGA
        ldd             [%o1 + 0x010], %f4              ! MS    Group19
        faligndata      %f14, %f0, %f30                 ! FGA
        stda            %f16, [%o0] ASI_BLK_P           ! MS    Group20
        ldd             [%o1 + 0x018], %f6              ! AX
        faligndata      %f0, %f2, %f16                  ! FGA   Group11 (7-cycle stall)
        ldd             [%o1 + 0x020], %f8              ! MS
        faligndata      %f2, %f4, %f18                  ! FGA   Group12
        ldd             [%o1 + 0x028], %f10             ! MS
        faligndata      %f4, %f6, %f20                  ! FGA   Group13
        ldd             [%o1 + 0x030], %f12             ! MS
        faligndata      %f6, %f8, %f22                  ! FGA   Group14
        ldd             [%o1 + 0x038], %f14             ! MS
        faligndata      %f8, %f10, %f24                 ! FGA   Group15
        cmp             %g1, 0                          ! A0
        be,pt           %icc, 1f                        ! BR
         add            %o0, 0x40, %o0                  ! A1
        ldd             [%o1 + 0x040], %f0              ! MS
1:      faligndata      %f10, %f12, %f26                ! FGA   Group16
        faligndata      %f12, %f14, %f28                ! FGA   Group17
        faligndata      %f14, %f0, %f30                 ! FGA   Group18
        stda            %f16, [%o0] ASI_BLK_P           ! MS
        add             %o0, 0x40, %o0                  ! A0
        add             %o1, 0x40, %o1                  ! A1
#ifdef __KERNEL__
        .globl          U3memcpy_nop_2_3
U3memcpy_nop_2_3:
        mov             PRIMARY_CONTEXT, %o3
        stxa            %g0, [%o3] ASI_DMMU             ! Flush P-cache
        stxa            %g3, [%g0] ASI_DCU_CONTROL_REG  ! Disable P-cache
#endif
        membar          #Sync                           ! MS    Group26 (7-cycle stall)

        /* Now we copy the (len modulo 64) bytes at the end.
         * Note how we borrow the %f0 loaded above.
         *
         * Also notice how this code is careful not to perform a
         * load past the end of the src buffer just like similar
         * code found in U3memcpy_toosmall processing.
         */
U3memcpy_loopend:
        and             %o2, 0x3f, %o2                  ! A0    Group
        andcc           %o2, 0x38, %g2                  ! A0    Group
        be,pn           %icc, U3memcpy_endcruft         ! BR
         subcc          %g2, 0x8, %g2                   ! A1
        be,pn           %icc, U3memcpy_endcruft         ! BR    Group
         cmp            %g1, 0                          ! A0

        be,a,pt         %icc, 1f                        ! BR    Group
         ldd            [%o1 + 0x00], %f0               ! MS

1:      ldd             [%o1 + 0x08], %f2               ! MS    Group
        add             %o1, 0x8, %o1                   ! A0
        sub             %o2, 0x8, %o2                   ! A1
        subcc           %g2, 0x8, %g2                   ! A0    Group
        faligndata      %f0, %f2, %f8                   ! FGA   Group
        std             %f8, [%o0 + 0x00]               ! MS    (XXX does it stall here? XXX)
        be,pn           %icc, U3memcpy_endcruft         ! BR
         add            %o0, 0x8, %o0                   ! A0
        ldd             [%o1 + 0x08], %f0               ! MS    Group
        add             %o1, 0x8, %o1                   ! A0
        sub             %o2, 0x8, %o2                   ! A1
        subcc           %g2, 0x8, %g2                   ! A0    Group
        faligndata      %f2, %f0, %f8                   ! FGA
        std             %f8, [%o0 + 0x00]               ! MS    (XXX does it stall here? XXX)
        bne,pn          %icc, 1b                        ! BR
         add            %o0, 0x8, %o0                   ! A0    Group

        /* If anything is left, we copy it one byte at a time.
         * Note that %g1 is (src & 0x3) saved above before the
         * alignaddr was performed.
         */
U3memcpy_endcruft:
        cmp             %o2, 0
        add             %o1, %g1, %o1
        VISExitHalf
        be,pn           %icc, U3memcpy_short_ret
         nop
        ba,a,pt         %xcc, U3memcpy_short

        /* If we get here, then 32 <= len < (6 * 64) */
U3memcpy_toosmall:

#ifdef SMALL_COPY_USES_FPU

        /* Is 'dst' already aligned on an 8-byte boundary? */
        be,pt           %xcc, 2f                        ! BR    Group

        /* Compute abs((dst & 7) - 8) into %g2.  This is the number
         * of bytes to copy to make 'dst' 8-byte aligned.  We pre-
         * subtract this from 'len'.
         */
         sub            %g2, 0x8, %g2                   ! A0
        sub             %g0, %g2, %g2                   ! A0    Group (reg-dep)
        sub             %o2, %g2, %o2                   ! A0    Group (reg-dep)

        /* Copy %g2 bytes from src to dst, one byte at a time. */
1:      ldub            [%o1 + 0x00], %o3               ! MS    (Group) (%o3 in 3 cycles)
        add             %o1, 0x1, %o1                   ! A1
        add             %o0, 0x1, %o0                   ! A0    Group
        subcc           %g2, 0x1, %g2                   ! A1

        bg,pt           %icc, 1b                        ! BR    Group
         stb            %o3, [%o0 + -1]                 ! MS    Group

2:      VISEntryHalf                                    ! MS+MS

        /* Compute (len - (len % 8)) into %g2.  This is guarenteed
         * to be nonzero.
         */
        andn            %o2, 0x7, %g2                   ! A0    Group

        /* You may read this and believe that it allows reading
         * one 8-byte longword past the end of src.  It actually
         * does not, as %g2 is subtracted as loads are done from
         * src, so we always stop before running off the end.
         * Also, we are guarenteed to have at least 0x10 bytes
         * to move here.
         */
        sub             %g2, 0x8, %g2                   ! A0    Group (reg-dep)
        alignaddr       %o1, %g0, %g1                   ! MS          (Break-after)
        ldd             [%g1 + 0x00], %f0               ! MS    Group (1-cycle stall)
        add             %g1, 0x8, %g1                   ! A0

1:      ldd             [%g1 + 0x00], %f2               ! MS    Group
        add             %g1, 0x8, %g1                   ! A0
        sub             %o2, 0x8, %o2                   ! A1
        subcc           %g2, 0x8, %g2                   ! A0    Group

        faligndata      %f0, %f2, %f8                   ! FGA   Group (1-cycle stall)
        std             %f8, [%o0 + 0x00]               ! MS    Group (2-cycle stall)
        add             %o1, 0x8, %o1                   ! A0
        be,pn           %icc, 2f                        ! BR

         add            %o0, 0x8, %o0                   ! A1
        ldd             [%g1 + 0x00], %f0               ! MS    Group
        add             %g1, 0x8, %g1                   ! A0
        sub             %o2, 0x8, %o2                   ! A1

        subcc           %g2, 0x8, %g2                   ! A0    Group
        faligndata      %f2, %f0, %f8                   ! FGA   Group (1-cycle stall)
        std             %f8, [%o0 + 0x00]               ! MS    Group (2-cycle stall)
        add             %o1, 0x8, %o1                   ! A0

        bne,pn          %icc, 1b                        ! BR
         add            %o0, 0x8, %o0                   ! A1

        /* Nothing left to copy? */
2:      cmp             %o2, 0                          ! A0    Group
        VISExitHalf                                     ! A0+MS
        be,pn           %icc, U3memcpy_short_ret        ! BR    Group
         nop                                            ! A0
        ba,a,pt         %xcc, U3memcpy_short            ! BR    Group

#else /* !(SMALL_COPY_USES_FPU) */

        xor             %o1, %o0, %g2
        andcc           %g2, 0x7, %g0
        bne,pn          %icc, U3memcpy_short
         andcc          %o1, 0x7, %g2

        be,pt           %xcc, 2f
         sub            %g2, 0x8, %g2
        sub             %g0, %g2, %g2
        sub             %o2, %g2, %o2

1:      ldub            [%o1 + 0x00], %o3
        add             %o1, 0x1, %o1
        add             %o0, 0x1, %o0
        subcc           %g2, 0x1, %g2
        bg,pt           %icc, 1b
         stb            %o3, [%o0 + -1]

2:      andn            %o2, 0x7, %g2
        sub             %o2, %g2, %o2

3:      ldx             [%o1 + 0x00], %o3
        add             %o1, 0x8, %o1
        add             %o0, 0x8, %o0
        subcc           %g2, 0x8, %g2
        bg,pt           %icc, 3b
         stx            %o3, [%o0 + -8]

        cmp             %o2, 0
        bne,pn          %icc, U3memcpy_short
         nop
        ba,a,pt         %xcc, U3memcpy_short_ret

#endif /* !(SMALL_COPY_USES_FPU) */