MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
   4 #
   5 # This program and the accompanying materials are licensed and made available
   6 # under the terms and conditions of the BSD License which accompanies this
   7 # distribution.  The full text of the license may be found at
   8 # http://opensource.org/licenses/bsd-license.php
   9 #
  10 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 #
  13 #------------------------------------------------------------------------------
  14
  15     .text
  16     .thumb
  17     .syntax unified
  18     .align  5
  19 ASM_GLOBAL ASM_PFX(InternalMemSetMem16)
  20 ASM_PFX(InternalMemSetMem16):
  21     uxth    r2, r2
  22     lsl     r1, r1, #1
  23     orr     r2, r2, r2, lsl #16
  24     b       0f
  25
  26 ASM_GLOBAL ASM_PFX(InternalMemSetMem32)
  27 ASM_PFX(InternalMemSetMem32):
  28     lsl     r1, r1, #2
  29     b       0f
  30
  31 ASM_GLOBAL ASM_PFX(InternalMemSetMem64)
  32 ASM_PFX(InternalMemSetMem64):
  33     lsl     r1, r1, #3
  34     b       1f
  35
  36     .align  5
  37 ASM_GLOBAL ASM_PFX(InternalMemSetMem)
  38 ASM_PFX(InternalMemSetMem):
  39     uxtb    r2, r2
  40     orr     r2, r2, r2, lsl #8
  41     orr     r2, r2, r2, lsl #16
  42     b       0f
  43
  44 ASM_GLOBAL ASM_PFX(InternalMemZeroMem)
  45 ASM_PFX(InternalMemZeroMem):
  46     movs    r2, #0
  47 0:  mov     r3, r2
  48
  49 1:  push    {r4, lr}
  50     cmp     r1, #16                 // fewer than 16 bytes of input?
  51     add     r1, r1, r0              // r1 := dst + length
  52     add     lr, r0, #16
  53     blt     2f
  54     bic     lr, lr, #15             // align output pointer
  55
  56     str     r2, [r0]                // potentially unaligned store of 4 bytes
  57     str     r3, [r0, #4]            // potentially unaligned store of 4 bytes
  58     str     r2, [r0, #8]            // potentially unaligned store of 4 bytes
  59     str     r3, [r0, #12]           // potentially unaligned store of 4 bytes
  60     beq     1f
  61
  62 0:  add     lr, lr, #16             // advance the output pointer by 16 bytes
  63     subs    r4, r1, lr              // past the output?
  64     blt     3f                      // break out of the loop
  65     strd    r2, r3, [lr, #-16]      // aligned store of 16 bytes
  66     strd    r2, r3, [lr, #-8]
  67     bne     0b                      // goto beginning of loop
  68 1:  pop     {r4, pc}
  69
  70 2:  subs    r4, r1, lr
  71 3:  adds    r4, r4, #16
  72     subs    r1, r1, #8
  73     cmp     r4, #4                  // between 4 and 15 bytes?
  74     blt     4f
  75     cmp     r4, #8                  // between 8 and 15 bytes?
  76     sub     r4, lr, #16
  77     str     r2, [r4]                // overlapping store of 4 + (4 + 4) + 4 bytes
  78     it      gt
  79     strgt.n r3, [r4, #4]
  80     it      gt
  81     strgt.n r2, [r1]
  82     str     r3, [r1, #4]
  83     pop     {r4, pc}
  84
  85 4:  cmp     r4, #2                  // 2 or 3 bytes?
  86     strb    r2, [lr, #-16]          // store 1 byte
  87     it      ge
  88     strhge.n r2, [r1, #6]           // store 2 bytes
  89     pop     {r4, pc}