ArmEbPkg/Sec/ModuleEntryPoint.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # ARM EB Entry point. Reset vector in FV header will brach to
   4 # _ModuleEntryPoint.
   5 #
   6 # We use crazy macros, like LoadConstantToReg, since Xcode assembler
   7 # does not support = assembly syntax for ldr.
   8 #
   9 # Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
  10 #
  11 # This program and the accompanying materials
  12 # are licensed and made available under the terms and conditions of the BSD License
  13 # which accompanies this distribution.  The full text of the license may be found at
  14 # http://opensource.org/licenses/bsd-license.php
  15 #
  16 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  17 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  18 #
  19 #------------------------------------------------------------------------------
  20
  21 #include <AsmMacroIoLib.h>
  22 #include <Base.h>
  23 #include <Library/PcdLib.h>
  24 #include <ArmEb/ArmEb.h>
  25
  26 .text
  27 .align 3
  28
  29 .globl ASM_PFX(CEntryPoint)
  30 .globl ASM_PFX(_ModuleEntryPoint)
  31
  32 ASM_PFX(_ModuleEntryPoint):
  33
  34   // Turn off remapping NOR to 0. We can now use DRAM in low memory
  35   MmioOr32 (EB_SP810_CTRL_BASE ,BIT8)
  36
  37   // Enable NEON register in case folks want to use them for optimizations (CopyMem)
  38   mrc     p15, 0, r0, c1, c0, 2
  39   orr     r0, r0, #0x00f00000   // Enable VPF access (V* instructions)
  40   mcr     p15, 0, r0, c1, c0, 2
  41   mov     r0, #0x40000000       // Set EN bit in FPEXC
  42   mcr     p10,#0x7,r0,c8,c0,#0  // msr     FPEXC,r0 in ARM assembly
  43
  44
  45   // Set CPU vectors to start of DRAM
  46   LoadConstantToReg (FixedPcdGet32(PcdCpuVectorBaseAddress) ,r0) // Get vector base
  47   mcr     p15, 0, r0, c12, c0, 0
  48   isb                               // Sync changes to control registers
  49
  50   // Fill vector table with branchs to current pc (jmp $)
  51   // CPU DXE driver likes known values so it can let GDB stub hook vectors
  52   ldr     r1, ShouldNeverGetHere
  53   movs    r2, #0
  54 FillVectors:
  55   str     r1, [r0, r2]
  56   adds    r2, r2, #4
  57   cmp     r2, #32
  58   bne     FillVectors
  59
  60   //
  61   // Set stack based on PCD values. Need to do it this way to make C code work
  62   // when it runs from FLASH.
  63   //
  64   LoadConstantToReg (FixedPcdGet32(PcdPrePiStackBase) ,r2)    // stack base arg2
  65   LoadConstantToReg (FixedPcdGet32(PcdPrePiStackSize) ,r3)    // stack size arg3
  66   add     r4, r2, r3
  67   mov     r13, r4
  68
  69   // Call C entry point
  70   LoadConstantToReg (FixedPcdGet32(PcdMemorySize) ,r1)    // memory size arg1
  71   LoadConstantToReg (FixedPcdGet32(PcdMemoryBase) ,r0)    // memory size arg0
  72   blx      ASM_PFX(CEntryPoint)
  73
  74 ShouldNeverGetHere:
  75   // _CEntryPoint should never return
  76   b       ShouldNeverGetHere
  77
  78