97 lines
2.8 KiB
ArmAsm
97 lines
2.8 KiB
ArmAsm
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/*
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* This file is part of the COMROGUE Operating System for Raspberry Pi
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*
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* Copyright (c) 2013, Eric J. Bowersox / Erbosoft Enterprises
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* All rights reserved.
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*
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* This program is free for commercial and non-commercial use as long as the following conditions are
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* adhered to.
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*
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* Copyright in this file remains Eric J. Bowersox and/or Erbosoft, and as such any copyright notices
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* in the code are not to be removed.
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice, this list of conditions and
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* the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
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* the following disclaimer in the documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* "Raspberry Pi" is a trademark of the Raspberry Pi Foundation.
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*/
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.section ".text"
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/*------------------------
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* Low-level IO functions
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*------------------------
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*/
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/*
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* Writes a 32-bit word of data to a memory-mapped IO port.
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*
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* Parameters:
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* - kaPort = Kernel address of the IO port to write to.
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* - uiData = Data to be written.
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*
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* Returns:
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* Nothing.
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*
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* Side effects:
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* Writing to any given IO port may have arbitrary side effects.
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*/
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.globl llIOWriteK
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llIOWriteK:
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str r1,[r0]
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bx lr
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/*
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* Reads a 32-bit word of data from a memory-mapped IO port.
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*
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* Parameters:
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* - kaPort = Kernel address of the IO port we read from.
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*
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* Returns:
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* The word of data read from the IO port.
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*
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* Side effects:
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* Reading from any given IO port may have arbitrary side effects.
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*/
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.globl llIOReadK
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llIOReadK:
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ldr r0,[r0]
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bx lr
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/*
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* Delays for a certain number of cycles, to allow an IO operation to work.
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*
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* Parameters:
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* - uiTicks = The number of "ticks" to delay.
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*
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* Returns:
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* Nothing.
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*/
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.globl llIODelay
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llIODelay:
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push {lr}
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.delaytop:
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nop
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nop
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bl .delayreturn
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nop
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nop
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subs r0, r0, #1
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bne .delaytop
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pop {lr}
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.delayreturn:
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bx lr
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