/*
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* Copyright (C) 2013 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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.text
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.balign 0
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.global scanline_col32cb16blend_arm64
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//
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// This function alpha blends a fixed color into a destination scanline, using
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// the formula:
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//
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// d = s + (((a + (a >> 7)) * d) >> 8)
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//
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// where d is the destination pixel,
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// s is the source color,
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// a is the alpha channel of the source color.
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//
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// x0 = destination buffer pointer
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// w1 = color value
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// w2 = count
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scanline_col32cb16blend_arm64:
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lsr w5, w1, #24 // shift down alpha
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mov w9, #0xff // create mask
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add w5, w5, w5, lsr #7 // add in top bit
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mov w4, #256 // create #0x100
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sub w5, w4, w5 // invert alpha
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and w10, w1, #0xff // extract red
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and w12, w9, w1, lsr #8 // extract green
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and w4, w9, w1, lsr #16 // extract blue
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lsl w10, w10, #5 // prescale red
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lsl w12, w12, #6 // prescale green
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lsl w4, w4, #5 // prescale blue
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lsr w9, w9, #2 // create dest green mask
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1:
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ldrh w8, [x0] // load dest pixel
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subs w2, w2, #1 // decrement loop counter
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lsr w6, w8, #11 // extract dest red
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and w7, w9, w8, lsr #5 // extract dest green
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and w8, w8, #0x1f // extract dest blue
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madd w6, w6, w5, w10 // dest red * alpha + src red
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madd w7, w7, w5, w12 // dest green * alpha + src green
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madd w8, w8, w5, w4 // dest blue * alpha + src blue
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lsr w6, w6, #8 // shift down red
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lsr w7, w7, #8 // shift down green
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lsl w6, w6, #11 // shift red into 565
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orr w6, w6, w7, lsl #5 // shift green into 565
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orr w6, w6, w8, lsr #8 // shift blue into 565
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strh w6, [x0], #2 // store pixel to dest, update ptr
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b.ne 1b // if count != 0, loop
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ret
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