arch/metag/lib/memset.S

   1 ! SPDX-License-Identifier: GPL-2.0
   2 !   Copyright (C) 2008-2012 Imagination Technologies Ltd.
   3
   4         .text
   5         .global _memset
   6         .type   _memset,function
   7 ! D1Ar1 dst
   8 ! D0Ar2 c
   9 ! D1Ar3 cnt
  10 ! D0Re0 dst
  11 _memset:
  12         AND     D0Ar2,D0Ar2,#0xFF       ! Ensure a byte input value
  13         MULW    D0Ar2,D0Ar2,#0x0101     ! Duplicate byte value into  0-15
  14         ANDS    D0Ar4,D1Ar1,#7          ! Extract bottom LSBs of dst
  15         LSL     D0Re0,D0Ar2,#16         ! Duplicate byte value into 16-31
  16         ADD     A0.2,D0Ar2,D0Re0        ! Duplicate byte value into 4 (A0.2)
  17         MOV     D0Re0,D1Ar1             ! Return dst
  18         BZ      $LLongStub              ! if start address is aligned
  19         ! start address is not aligned on an 8 byte boundary, so we
  20         ! need the number of bytes up to the next 8 byte address
  21         ! boundary, or the length of the string if less than 8, in D1Ar5
  22         MOV     D0Ar2,#8                ! Need 8 - N in D1Ar5 ...
  23         SUB     D1Ar5,D0Ar2,D0Ar4       !            ... subtract N
  24         CMP     D1Ar3,D1Ar5
  25         MOVMI   D1Ar5,D1Ar3
  26         B       $LByteStub              ! dst is mis-aligned, do $LByteStub
  27
  28 !
  29 ! Preamble to LongLoop which generates 4*8 bytes per interation (5 cycles)
  30 !
  31 $LLongStub:
  32         LSRS    D0Ar2,D1Ar3,#5
  33         AND     D1Ar3,D1Ar3,#0x1F
  34         MOV     A1.2,A0.2
  35         BEQ     $LLongishStub
  36         SUB     TXRPT,D0Ar2,#1
  37         CMP     D1Ar3,#0
  38 $LLongLoop:
  39         SETL    [D1Ar1++],A0.2,A1.2
  40         SETL    [D1Ar1++],A0.2,A1.2
  41         SETL    [D1Ar1++],A0.2,A1.2
  42         SETL    [D1Ar1++],A0.2,A1.2
  43         BR      $LLongLoop
  44         BZ      $Lexit
  45 !
  46 ! Preamble to LongishLoop which generates 1*8 bytes per interation (2 cycles)
  47 !
  48 $LLongishStub:
  49         LSRS    D0Ar2,D1Ar3,#3
  50         AND     D1Ar3,D1Ar3,#0x7
  51         MOV     D1Ar5,D1Ar3
  52         BEQ     $LByteStub
  53         SUB     TXRPT,D0Ar2,#1
  54         CMP     D1Ar3,#0
  55 $LLongishLoop:
  56         SETL    [D1Ar1++],A0.2,A1.2
  57         BR      $LLongishLoop
  58         BZ      $Lexit
  59 !
  60 ! This does a byte structured burst of up to 7 bytes
  61 !
  62 !       D1Ar1 should point to the location required
  63 !       D1Ar3 should be the remaining total byte count
  64 !       D1Ar5 should be burst size (<= D1Ar3)
  65 !
  66 $LByteStub:
  67         SUBS    D1Ar3,D1Ar3,D1Ar5       ! Reduce count
  68         ADD     D1Ar1,D1Ar1,D1Ar5       ! Advance pointer to end of area
  69         MULW    D1Ar5,D1Ar5,#4          ! Scale to (1*4), (2*4), (3*4)
  70         SUB     D1Ar5,D1Ar5,#(8*4)      ! Rebase to -(7*4), -(6*4), -(5*4), ...
  71         MOV     A1.2,D1Ar5
  72         SUB     PC,CPC1,A1.2            ! Jump into table below
  73         SETB    [D1Ar1+#(-7)],A0.2
  74         SETB    [D1Ar1+#(-6)],A0.2
  75         SETB    [D1Ar1+#(-5)],A0.2
  76         SETB    [D1Ar1+#(-4)],A0.2
  77         SETB    [D1Ar1+#(-3)],A0.2
  78         SETB    [D1Ar1+#(-2)],A0.2
  79         SETB    [D1Ar1+#(-1)],A0.2
  80 !
  81 ! Return if all data has been output, otherwise do $LLongStub
  82 !
  83         BNZ     $LLongStub
  84 $Lexit:
  85         MOV     PC,D1RtP
  86         .size _memset,.-_memset
  87