--- /dev/null
+//------------------------------------------------------------------------------
+//
+// Copyright (c) 2008-2009 Apple Inc. All rights reserved.
+//
+// All rights reserved. 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.
+//
+//------------------------------------------------------------------------------
+
+
+
+/*
+
+This is the stack constructed by the exception handler
+
+ R0 0x00 # stmfd SP!,{R0-R12}
+ R1 0x04
+ R2 0x08
+ R3 0x0c
+ R4 0x10
+ R5 0x14
+ R6 0x18
+ R7 0x1c
+ R8 0x20
+ R9 0x24
+ R10 0x28
+ R11 0x2c
+ R12 0x30
+ SP 0x34 # reserved via adding 0x20 (32) to the SP
+ LR 0x38
+ PC 0x3c
+ CPSR 0x40
+ DFSR 0x44
+ DFAR 0x48
+ IFSR 0x4c
+ IFAR 0x50
+
+ LR 0x54 # SVC Link register (we need to restore it)
+
+ LR 0x58 # pushed by srsfd
+ CPSR 0x5c # pushed by srsfd
+
+ */
+
+
+ EXPORT ExceptionHandlersStart
+ EXPORT ExceptionHandlersEnd
+ EXPORT CommonExceptionEntry
+ EXPORT AsmCommonExceptionEntry
+ IMPORT CommonCExceptionHandler
+
+ PRESERVE8
+ AREA DxeExceptionHandlers, CODE, READONLY
+
+ExceptionHandlersStart
+
+Reset
+ b ResetEntry
+
+UndefinedInstruction
+ b UndefinedInstructionEntry
+
+SoftwareInterrupt
+ b SoftwareInterruptEntry
+
+PrefetchAbort
+ b PrefetchAbortEntry
+
+DataAbort
+ b DataAbortEntry
+
+ReservedException
+ b ReservedExceptionEntry
+
+Irq
+ b IrqEntry
+
+Fiq
+ b FiqEntry
+
+ResetEntry
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid if,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#0
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+UndefinedInstructionEntry
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid i,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#1
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+SoftwareInterruptEntry
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid i,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#2
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+PrefetchAbortEntry
+ sub LR,LR,#4
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid i,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#3
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+DataAbortEntry
+ sub LR,LR,#8
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid i,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#4
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+ReservedExceptionEntry
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid if,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#5
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+IrqEntry
+ sub LR,LR,#4
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid i,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#6
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+FiqEntry
+ sub LR,LR,#4
+ srsfd #0x13! ; Store return state on SVC stack
+ cpsid if,#0x13 ; Switch to SVC for common stack
+ stmfd SP!,{LR} ; Store the link register for the current mode
+ sub SP,SP,#0x20 ; Save space for SP, LR, PC, IFAR - CPSR
+ stmfd SP!,{R0-R12} ; Store the register state
+
+ mov R0,#7
+ ldr R1,CommonExceptionEntry
+ bx R1
+
+CommonExceptionEntry
+ dcd 0x12345678
+
+ExceptionHandlersEnd
+
+AsmCommonExceptionEntry
+ mrc p15, 0, R1, c6, c0, 2 ; Read IFAR
+ str R1, [SP, #0x50] ; Store it in EFI_SYSTEM_CONTEXT_ARM.IFAR
+
+ mrc p15, 0, R1, c5, c0, 1 ; Read IFSR
+ str R1, [SP, #0x4c] ; Store it in EFI_SYSTEM_CONTEXT_ARM.IFSR
+
+ mrc p15, 0, R1, c6, c0, 0 ; Read DFAR
+ str R1, [SP, #0x48] ; Store it in EFI_SYSTEM_CONTEXT_ARM.DFAR
+
+ mrc p15, 0, R1, c5, c0, 0 ; Read DFSR
+ str R1, [SP, #0x44] ; Store it in EFI_SYSTEM_CONTEXT_ARM.DFSR
+
+ ldr R1, [SP, #0x5c] ; srsfd saved pre-exception CPSR on the stack
+ str R1, [SP, #0x40] ; Store it in EFI_SYSTEM_CONTEXT_ARM.CPSR
+
+ ldr R1, [SP, #0x58] ; PC is the LR pushed by srsfd
+ str R1, [SP, #0x3c] ; Store it in EFI_SYSTEM_CONTEXT_ARM.PC
+ str R1, [SP, #0x38] ; Store it in EFI_SYSTEM_CONTEXT_ARM.LR
+
+ sub R1, SP, #0x60 ; We pused 0x60 bytes on the stack
+ str R1, [SP, #0x34] ; Store it in EFI_SYSTEM_CONTEXT_ARM.SP
+
+ ; R0 is exception type
+ mov R1,SP ; Prepare System Context pointer as an argument for the exception handler
+ blx CommonCExceptionHandler ; Call exception handler
+
+ ldr R2,[SP,#0x40] ; EFI_SYSTEM_CONTEXT_ARM.CPSR
+ str R2,[SP,#0x5c] ; Store it back to srsfd stack slot so it can be restored
+
+ ldr R2,[SP,#0x3c] ; EFI_SYSTEM_CONTEXT_ARM.PC
+ str R2,[SP,#0x58] ; Store it back to srsfd stack slot so it can be restored
+
+ ldmfd SP!,{R0-R12} ; Restore general purpose registers
+ ; Exception handler can not change SP or LR as we would blow chunks
+
+ add SP,SP,#0x20 ; Clear out the remaining stack space
+ ldmfd SP!,{LR} ; restore the link register for this context
+ rfefd SP! ; return from exception via srsfd stack slot
+
+ END
+
+
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