1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 .text 29 .balign 0 30 31 .global scanline_col32cb16blend_arm64 32 33 // 34 // This function alpha blends a fixed color into a destination scanline, using 35 // the formula: 36 // 37 // d = s + (((a + (a >> 7)) * d) >> 8) 38 // 39 // where d is the destination pixel, 40 // s is the source color, 41 // a is the alpha channel of the source color. 42 // 43 44 // x0 = destination buffer pointer 45 // w1 = color value 46 // w2 = count 47 48 49 scanline_col32cb16blend_arm64: 50 51 lsr w5, w1, #24 // shift down alpha 52 mov w9, #0xff // create mask 53 add w5, w5, w5, lsr #7 // add in top bit 54 mov w4, #256 // create #0x100 55 sub w5, w4, w5 // invert alpha 56 and w10, w1, #0xff // extract red 57 and w12, w9, w1, lsr #8 // extract green 58 and w4, w9, w1, lsr #16 // extract blue 59 lsl w10, w10, #5 // prescale red 60 lsl w12, w12, #6 // prescale green 61 lsl w4, w4, #5 // prescale blue 62 lsr w9, w9, #2 // create dest green mask 63 64 1: 65 ldrh w8, [x0] // load dest pixel 66 subs w2, w2, #1 // decrement loop counter 67 lsr w6, w8, #11 // extract dest red 68 and w7, w9, w8, lsr #5 // extract dest green 69 and w8, w8, #0x1f // extract dest blue 70 71 madd w6, w6, w5, w10 // dest red * alpha + src red 72 madd w7, w7, w5, w12 // dest green * alpha + src green 73 madd w8, w8, w5, w4 // dest blue * alpha + src blue 74 75 lsr w6, w6, #8 // shift down red 76 lsr w7, w7, #8 // shift down green 77 lsl w6, w6, #11 // shift red into 565 78 orr w6, w6, w7, lsl #5 // shift green into 565 79 orr w6, w6, w8, lsr #8 // shift blue into 565 80 81 strh w6, [x0], #2 // store pixel to dest, update ptr 82 b.ne 1b // if count != 0, loop 83 84 ret 85 86 87 88
