blob: 18a01fd6834f0120390773392a0880f8882d9a76 [file] [log] [blame]
/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
.text
.align
.global scanline_col32cb16blend_arm64
//
// This function alpha blends a fixed color into a destination scanline, using
// the formula:
//
// d = s + (((a + (a >> 7)) * d) >> 8)
//
// where d is the destination pixel,
// s is the source color,
// a is the alpha channel of the source color.
//
// x0 = destination buffer pointer
// w1 = color value
// w2 = count
scanline_col32cb16blend_arm64:
lsr w5, w1, #24 // shift down alpha
mov w9, #0xff // create mask
add w5, w5, w5, lsr #7 // add in top bit
mov w4, #256 // create #0x100
sub w5, w4, w5 // invert alpha
and w10, w1, #0xff // extract red
and w12, w9, w1, lsr #8 // extract green
and w4, w9, w1, lsr #16 // extract blue
lsl w10, w10, #5 // prescale red
lsl w12, w12, #6 // prescale green
lsl w4, w4, #5 // prescale blue
lsr w9, w9, #2 // create dest green mask
1:
ldrh w8, [x0] // load dest pixel
subs w2, w2, #1 // decrement loop counter
lsr w6, w8, #11 // extract dest red
and w7, w9, w8, lsr #5 // extract dest green
and w8, w8, #0x1f // extract dest blue
madd w6, w6, w5, w10 // dest red * alpha + src red
madd w7, w7, w5, w12 // dest green * alpha + src green
madd w8, w8, w5, w4 // dest blue * alpha + src blue
lsr w6, w6, #8 // shift down red
lsr w7, w7, #8 // shift down green
lsl w6, w6, #11 // shift red into 565
orr w6, w6, w7, lsl #5 // shift green into 565
orr w6, w6, w8, lsr #8 // shift blue into 565
strh w6, [x0], #2 // store pixel to dest, update ptr
b.ne 1b // if count != 0, loop
ret