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path: root/ArmEbPkg/Sec/ModuleEntryPoint.asm
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//------------------------------------------------------------------------------ 
//
// Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
//
// This program and the accompanying materials
// are licensed and made available under the terms and conditions of the BSD License
// which accompanies this distribution.  The full text of the license may be found at
// http://opensource.org/licenses/bsd-license.php
//
// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
//
//------------------------------------------------------------------------------

#include <AsmMacroIoLib.h>
#include <Base.h>
#include <Library/PcdLib.h>
#include <ArmEb/ArmEb.h>
#include <AutoGen.h>

  INCLUDE AsmMacroIoLib.inc
  
  IMPORT  CEntryPoint
  EXPORT  _ModuleEntryPoint
        
  PRESERVE8
  AREA    ModuleEntryPoint, CODE, READONLY
  

_ModuleEntryPoint
 
  // Turn off remapping NOR to 0. We can now use DRAM in low memory
  MmioOr32 (0x10001000 ,BIT8) //EB_SP810_CTRL_BASE

  // Enable NEON register in case folks want to use them for optimizations (CopyMem)
  mrc     p15, 0, r0, c1, c0, 2
  orr     r0, r0, #0x00f00000   // Enable VPF access (V* instructions)
  mcr     p15, 0, r0, c1, c0, 2
  mov     r0, #0x40000000       // Set EN bit in FPEXC
  mcr     p10,#0x7,r0,c8,c0,#0  // msr     FPEXC,r0 in ARM assembly
   
  // Set CPU vectors to start of DRAM
  LoadConstantToReg (FixedPcdGet32(PcdCpuVectorBaseAddress) ,r0) // Get vector base
  mcr     p15, 0, r0, c12, c0, 0
  isb                               // Sync changes to control registers

  // Fill vector table with branchs to current pc (jmp $)
  // CPU DXE driver likes known values so it can let GDB stub hook vectors
  ldr     r1, ShouldNeverGetHere
  movs    r2, #0
FillVectors
  str     r1, [r0, r2]
  adds    r2, r2, #4
  cmp     r2, #32
  bne     FillVectors

  //
  // Set stack based on PCD values. Need to do it this way to make C code work 
  // when it runs from FLASH. 
  //  
  LoadConstantToReg (FixedPcdGet32(PcdPrePiStackBase) ,r2)    // stack base arg2  
  LoadConstantToReg (FixedPcdGet32(PcdPrePiStackSize) ,r3)    // stack size arg3  
  add     r4, r2, r3
  mov     r13, r4

  // Call C entry point
  LoadConstantToReg (FixedPcdGet32(PcdMemorySize) ,r1)    // memory size arg1      
  LoadConstantToReg (FixedPcdGet32(PcdMemoryBase) ,r0)    // memory size arg0       
  blx     CEntryPoint 

ShouldNeverGetHere
  // _CEntryPoint should never return 
  b       ShouldNeverGetHere
  
  END