/*---------------------------------------------------------------------------------

  Copyright (C) 2005 - 2017
  	Dave Murphy (WinterMute)

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any
  damages arising from the use of this software.

  Permission is granted to anyone to use this software for any
  purpose, including commercial applications, and to alter it and
  redistribute it freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you
     must not claim that you wrote the original software. If you use
     this software in a product, an acknowledgment in the product
     documentation would be appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and
     must not be misrepresented as being the original software.
  3. This notice may not be removed or altered from any source
     distribution.

---------------------------------------------------------------------------------*/

@---------------------------------------------------------------------------------
@ DS processor selection
@---------------------------------------------------------------------------------
	.arch	armv5te
	.cpu	arm946e-s
@---------------------------------------------------------------------------------


@---------------------------------------------------------------------------------
	.section ".crt0","ax"
	.global _start
@---------------------------------------------------------------------------------
	.align	4
	.arm
@---------------------------------------------------------------------------------
_start:
@---------------------------------------------------------------------------------
	push	{lr}

	ldr	r0, =__bss_start__	@ Clear BSS section
	ldr	r1, =__bss_end__
	sub	r1, r1, r0
	bl	ClearMem

	ldr	r0, =installException
	blx	r0

	pop	{lr}

	bx	lr

	.pool

@---------------------------------------------------------------------------------
@ Clear memory to 0x00 if length != 0
@  r0 = Start Address
@  r1 = Length
@---------------------------------------------------------------------------------
ClearMem:
@---------------------------------------------------------------------------------
	mov	r2, #3			@ Round down to nearest word boundary
	add	r1, r1, r2		@ Shouldn't be needed
	bics	r1, r1, r2	@ Clear 2 LSB (and set Z)
	bxeq	lr			@ Quit if copy size is 0

	mov	r2, #0
ClrLoop:
	stmia	r0!, {r2}
	subs	r1, r1, #4
	bne	ClrLoop

	bx	lr


@---------------------------------------------------------------------------------
@ Copy memory if length	!= 0
@  r1 = Source Address
@  r2 = Dest Address
@  r4 = Dest Address + Length
@---------------------------------------------------------------------------------
CopyMemCheck:
@---------------------------------------------------------------------------------
	sub	r3, r4, r2		@ Is there any data to copy?
@---------------------------------------------------------------------------------
@ Copy memory
@  r1 = Source Address
@  r2 = Dest Address
@  r3 = Length
@---------------------------------------------------------------------------------
CopyMem:
@---------------------------------------------------------------------------------
	mov	r0, #3			@ These commands are used in cases where
	add	r3, r3, r0		@ the length is not a multiple of 4,
	bics	r3, r3, r0	@ even though it should be.
	bxeq	lr			@ Length is zero, so exit
CIDLoop:
	ldmia	r1!, {r0}
	stmia	r2!, {r0}
	subs	r3, r3, #4
	bne	CIDLoop

	bx	lr

	.align 2