38 lines
1.2 KiB
ArmAsm
38 lines
1.2 KiB
ArmAsm
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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright (c) 2014, Normmatt
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*
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* Alternatively, the contents of this file may be used under the terms
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* of the GNU General Public License Version 2, as described below:
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*
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* This file is free software: you may copy, redistribute and/or modify
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* it under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 2 of the License, or (at your
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* option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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* Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see http://www.gnu.org/licenses/.
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*/
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.arm
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.global ioDelay
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.type ioDelay STT_FUNC
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@ioDelay ( u32 us )
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ioDelay:
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ldr r1, =0x18000000 @ VRAM
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1:
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@ Loop doing uncached reads from VRAM to make loop timing more reliable
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ldr r2, [r1]
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subs r0, #1
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bgt 1b
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bx lr
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