MdePkg/Library/BaseSynchronizationLib/RiscV64/Synchronization.S

   1 //------------------------------------------------------------------------------
   2 //
   3 // RISC-V synchronization functions.
   4 //
   5 // Copyright (c) 2020, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
   6 //
   7 // SPDX-License-Identifier: BSD-2-Clause-Patent
   8 //
   9 //------------------------------------------------------------------------------
  10 #include <Base.h>
  11
  12 .data
  13
  14 .text
  15 .align 3
  16
  17 .global ASM_PFX(InternalSyncCompareExchange32)
  18 .global ASM_PFX(InternalSyncCompareExchange64)
  19 .global ASM_PFX(InternalSyncIncrement)
  20 .global ASM_PFX(InternalSyncDecrement)
  21
  22 //
  23 // ompare and xchange a 32-bit value.
  24 //
  25 // @param a0 : Pointer to 32-bit value.
  26 // @param a1 : Compare value.
  27 // @param a2 : Exchange value.
  28 //
  29 ASM_PFX (InternalSyncCompareExchange32):
  30     lr.w  a3, (a0)        // Load the value from a0 and make
  31                           // the reservation of address.
  32     bne   a3, a1, exit
  33     sc.w  a3, a2, (a0)    // Write the value back to the address.
  34     mv    a3, a1
  35 exit:
  36     mv    a0, a3
  37     ret
  38
  39 .global ASM_PFX(InternalSyncCompareExchange64)
  40
  41 //
  42 // Compare and xchange a 64-bit value.
  43 //
  44 // @param a0 : Pointer to 64-bit value.
  45 // @param a1 : Compare value.
  46 // @param a2 : Exchange value.
  47 //
  48 ASM_PFX (SyncCompareExchange64):
  49     lr.d  a3, (a0)       // Load the value from a0 and make
  50                          // the reservation of address.
  51     bne   a3, a1, exit
  52     sc.d  a3, a2, (a0)   // Write the value back to the address.
  53     mv    a3, a1
  54 exit2:
  55     mv    a0, a3
  56     ret
  57
  58 //
  59 // Performs an atomic increment of an 32-bit unsigned integer.
  60 //
  61 // @param a0 : Pointer to 32-bit value.
  62 //
  63 ASM_PFX (InternalSyncIncrement):
  64     li  a1, 1
  65     amoadd.w  a2, a1, (a0)
  66     mv  a0, a2
  67     ret
  68
  69 //
  70 // Performs an atomic decrement of an 32-bit unsigned integer.
  71 //
  72 // @param a0 : Pointer to 32-bit value.
  73 //
  74 ASM_PFX (InternalSyncDecrement):
  75     li  a1, -1
  76     amoadd.w  a2, a1, (a0)
  77     mv  a0, a2
  78     ret