MdePkg/Library/BaseRiscVSbiLib/RiscVSbiEcall.S

   1 //------------------------------------------------------------------------------
   2 //
   3 // Make ECALL to SBI
   4 //
   5 // Copyright (c) 2023, Ventana Micro Systems Inc. All rights reserved.<BR>
   6 //
   7 // SPDX-License-Identifier: BSD-2-Clause-Patent
   8 //
   9 //------------------------------------------------------------------------------
  10
  11 #include <Register/RiscV64/RiscVImpl.h>
  12
  13 .data
  14 .align 3
  15 .section .text
  16
  17 //
  18 // Make ECALL to SBI
  19 // ecall updates the same a0 and a1 registers with
  20 // return values. Hence, the C function which calls
  21 // this should pass the address of Arg0 and Arg1.
  22 // This routine saves the address and updates it
  23 // with a0 and a1 once ecall returns.
  24 //
  25 // @param a0 : Pointer to Arg0
  26 // @param a1 : Pointer to Arg1
  27 // @param a2 : Arg2
  28 // @param a3 : Arg3
  29 // @param a4 : Arg4
  30 // @param a5 : Arg5
  31 // @param a6 : FunctionID
  32 // @param a7 : ExtensionId
  33 //
  34 ASM_FUNC (RiscVSbiEcall)
  35   mv t0, a0
  36   mv t1, a1
  37   ld a0, 0(a0)
  38   ld a1, 0(a1)
  39   ecall
  40   sd a0, 0(t0)
  41   sd a1, 0(t1)
  42   ret