/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2007 by Michael Sevakis * * ARM code for memory framebuffer LCDs * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "config.h" #include "cpu.h" /**************************************************************************** * void lcd_copy_buffer_rect(fb_data *dst, fb_data *src, int width, * int height); */ .section .icode, "ax", %progbits .align 2 .global lcd_copy_buffer_rect .type lcd_copy_buffer_rect, %function @ r0 = dst @ r1 = src @ r2 = width @ r3 = height lcd_copy_buffer_rect: @ stmfd sp!, { r4-r12, lr } @ save non-scratch regs mov r5, r2 @ r5 = cached width rsb r4, r2, #LCD_WIDTH @ r4 = LCD_WIDTH - width 10: @ copy line @ subs r2, r5, #1 @ r2 = width - 1 beq 40f @ finish line @ one halfword? skip to trailing copy tst r0, #2 @ word aligned? beq 20f @ rem copy @ yes? skip to word copy ldrh r6, [r1], #2 @ copy leading halfword subs r2, r2, #1 @ strh r6, [r0], #2 @ ble 40f @ finish line @ next line if lt or finish @ trailing halfword if eq 20: @ rem copy @ add r14, r2, #1 @ get remaining width mod 16 after word @ align (rw) and r14, r14, #0xe @ r14 = 0 (16), 2, 4, 6, 8, 10, 12, 14 add pc, pc, r14, lsl #3 @ branch to 32-byte align nop @ b 30f @ rw % 16 = 0 or 1? use octword loop nop @ nop @ nop @ ldr r6, [r1], #4 @ rw % 16 = 2 or 3 subs r2, r2, #2 @ str r6, [r0], #4 @ b 25f @ copy up done @ ldmia r1!, { r6-r7 } @ rw % 16 = 4 or 5 subs r2, r2, #4 @ stmia r0!, { r6-r7 } @ b 25f @ copy up done @ ldmia r1!, { r6-r8 } @ rw % 16 = 6 or 7 subs r2, r2, #6 @ stmia r0!, { r6-r8 } @ b 25f @ copy up done @ ldmia r1!, { r6-r9 } @ rw % 16 = 8 or 9 subs r2, r2, #8 @ stmia r0!, { r6-r9 } @ b 25f @ copy up done @ ldmia r1!, { r6-r10 } @ rw % 16 = 10 or 11 subs r2, r2, #10 @ stmia r0!, { r6-r10 } @ b 25f @ copy up done @ ldmia r1!, { r6-r11 } @ rw % 16 = 12 or 13 subs r2, r2, #12 @ stmia r0!, { r6-r11 } @ b 25f @ copy up done @ ldmia r1!, { r6-r12 } @ rw % 16 = 14 or 15 subs r2, r2, #14 @ stmia r0!, { r6-r12 } @ 25: @ copy up done @ ble 40f @ finish line @ no 32-byte segments remaining? 30: @ octword loop @ copy 16 pixels per loop ldmia r1!, { r6-r12, r14 } @ subs r2, r2, #16 @ stmia r0!, { r6-r12, r14 } @ bgt 30b @ octword loop @ 40: @ finish line @ ldreqh r6, [r1], #2 @ finish last halfword if eq ... add r1, r1, r4, lsl #1 @ streqh r6, [r0], #2 @ ... add r0, r0, r4, lsl #1 @ subs r3, r3, #1 @ next line bgt 10b @ copy line @ ldmfd sp!, { r4-r12, pc } @ restore regs and return .ltorg @ dump constant pool .size lcd_copy_buffer_rect, .-lcd_copy_buffer_rect /**************************************************************************** * void lcd_write_yuv_420_lines(fb_data *dst, * unsigned char const * const src[3], * int width, * int stride); * * |R| |1.000000 -0.000001 1.402000| |Y'| * |G| = |1.000000 -0.334136 -0.714136| |Pb| * |B| |1.000000 1.772000 0.000000| |Pr| * Scaled, normalized, rounded and tweaked to yield RGB 565: * |R| |74 0 101| |Y' - 16| >> 9 * |G| = |74 -24 -51| |Cb - 128| >> 8 * |B| |74 128 0| |Cr - 128| >> 9 * * Write four RGB565 pixels in the following order on each loop: * 1 3 + > down * 2 4 \/ left */ .section .icode, "ax", %progbits .align 2 .global lcd_write_yuv420_lines .type lcd_write_yuv420_lines, %function lcd_write_yuv420_lines: @ r0 = dst @ r1 = yuv_src @ r2 = width @ r3 = stride stmfd sp!, { r4-r12 } @ save non-scratch ldmia r1, { r4, r5, r6 } @ r4 = yuv_src[0] = Y'_p @ r5 = yuv_src[1] = Cb_p @ r6 = yuv_src[2] = Cr_p @ r1 = scratch sub r3, r3, #1 @ 10: @ loop line @ ldrb r7, [r4], #1 @ r7 = *Y'_p++; ldrb r8, [r5], #1 @ r8 = *Cb_p++; ldrb r9, [r6], #1 @ r9 = *Cr_p++; @ sub r7, r7, #16 @ r7 = Y = (Y' - 16)*74 add r12, r7, r7, asl #2 @ actually (Y' - 16)*37 and shift right add r7, r12, r7, asl #5 @ by one less when adding - same for all @ sub r8, r8, #128 @ Cb -= 128 sub r9, r9, #128 @ Cr -= 128 @ add r10, r9, r9, asl #1 @ r10 = Cr*51 + Cb*24 add r10, r10, r10, asl #4 @ add r10, r10, r8, asl #3 @ add r10, r10, r8, asl #4 @ @ add r11, r9, r9, asl #2 @ r9 = Cr*101 add r11, r11, r9, asl #5 @ add r9, r11, r9, asl #6 @ @ add r8, r8, #2 @ r8 = bu = (Cb*128 + 128) >> 8 mov r8, r8, asr #2 @ add r9, r9, #256 @ r9 = rv = (r9 + 256) >> 9 mov r9, r9, asr #9 @ rsb r10, r10, #128 @ r10 = guv = (-r10 + 128) >> 8 mov r10, r10, asr #8 @ @ compute R, G, and B add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv @ orr r12, r1, r11 @ check if clamping is needed... orr r12, r12, r7, asr #1 @ ...at all cmp r12, #31 @ bls 15f @ no clamp @ cmp r1, #31 @ clamp b mvnhi r1, r1, asr #31 @ andhi r1, r1, #31 @ cmp r11, #31 @ clamp r mvnhi r11, r11, asr #31 @ andhi r11, r11, #31 @ cmp r7, #63 @ clamp g mvnhi r7, r7, asr #31 @ andhi r7, r7, #63 @ 15: @ no clamp @ @ ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride) @ orr r1, r1, r7, lsl #5 @ r4 |= (g << 5) orr r1, r1, r11, lsl #11 @ r4 = b | (r << 11) #if LCD_WIDTH >= LCD_HEIGHT strh r1, [r0] @ #elif LCD_WIDTH < 256 strh r1, [r0], #LCD_WIDTH @ store pixel #else strh r1, [r0] @ #endif @ sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74 add r12, r7, r7, asl #2 @ add r7, r12, r7, asl #5 @ @ compute R, G, and B add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv @ orr r12, r1, r11 @ check if clamping is needed... orr r12, r12, r7, asr #1 @ ...at all cmp r12, #31 @ bls 15f @ no clamp @ cmp r1, #31 @ clamp b mvnhi r1, r1, asr #31 @ andhi r1, r1, #31 @ cmp r11, #31 @ clamp r mvnhi r11, r11, asr #31 @ andhi r11, r11, #31 @ cmp r7, #63 @ clamp g mvnhi r7, r7, asr #31 @ andhi r7, r7, #63 @ 15: @ no clamp @ @ ldrb r12, [r4], #1 @ r12 = Y' = *(Y'_p++) @ orr r1, r1, r11, lsl #11 @ r1 = b | (r << 11) orr r1, r1, r7, lsl #5 @ r1 |= (g << 5) #if LCD_WIDTH >= LCD_HEIGHT add r0, r0, #2*LCD_WIDTH @ strh r1, [r0] @ store pixel sub r0, r0, #2*LCD_WIDTH @ #elif LCD_WIDTH < 256 strh r1, [r0, #-LCD_WIDTH-2] @ store pixel #else strh r1, [r0, #-2] @ add r0, r0, #LCD_WIDTH @ #endif @ sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74 add r12, r7, r7, asl #2 @ add r7, r12, r7, asl #5 @ @ compute R, G, and B add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv @ orr r12, r1, r11 @ check if clamping is needed... orr r12, r12, r7, asr #1 @ ...at all cmp r12, #31 @ bls 15f @ no clamp @ cmp r1, #31 @ clamp b mvnhi r1, r1, asr #31 @ andhi r1, r1, #31 @ cmp r11, #31 @ clamp r mvnhi r11, r11, asr #31 @ andhi r11, r11, #31 @ cmp r7, #63 @ clamp g mvnhi r7, r7, asr #31 @ andhi r7, r7, #63 @ 15: @ no clamp @ @ ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride) @ orr r1, r1, r7, lsl #5 @ r1 = b | (g << 5) orr r1, r1, r11, lsl #11 @ r1 |= (r << 11) #if LCD_WIDTH >= LCD_HEIGHT strh r1, [r0, #2] #elif LCD_WIDTH < 256 strh r1, [r0, #LCD_WIDTH]! @ store pixel #else strh r1, [r0] @ #endif @ sub r7, r12, #16 @ r7 = Y = (Y' - 16)*74 add r12, r7, r7, asl #2 @ add r7, r12, r7, asl #5 @ @ compute R, G, and B add r1, r8, r7, asr #8 @ r1 = b = (Y >> 9) + bu add r11, r9, r7, asr #8 @ r11 = r = (Y >> 9) + rv add r7, r10, r7, asr #7 @ r7 = g = (Y >> 8) + guv @ orr r12, r1, r11 @ check if clamping is needed... orr r12, r12, r7, asr #1 @ ...at all cmp r12, #31 @ bls 15f @ no clamp @ cmp r1, #31 @ clamp b mvnhi r1, r1, asr #31 @ andhi r1, r1, #31 @ cmp r11, #31 @ clamp r mvnhi r11, r11, asr #31 @ andhi r11, r11, #31 @ cmp r7, #63 @ clamp g mvnhi r7, r7, asr #31 @ andhi r7, r7, #63 @ 15: @ no clamp @ @ orr r12, r1, r11, lsl #11 @ r12 = b | (r << 11) orr r12, r12, r7, lsl #5 @ r12 |= (g << 5) #if LCD_WIDTH >= LCD_HEIGHT add r0, r0, #2*LCD_WIDTH strh r12, [r0, #2] #if LCD_WIDTH <= 512 sub r0, r0, #(2*LCD_WIDTH)-4 #else sub r0, r0, #(2*LCD_WIDTH) add r0, r0, #4 #endif #else strh r12, [r0, #-2] @ store pixel #if LCD_WIDTH < 256 add r0, r0, #2*LCD_WIDTH @ #else add r0, r0, #LCD_WIDTH @ #endif #endif @ subs r2, r2, #2 @ subtract block from width bgt 10b @ loop line @ @ ldmfd sp!, { r4-r12 } @ restore registers and return bx lr @ .ltorg @ dump constant pool .size lcd_write_yuv420_lines, .-lcd_write_yuv420_lines /**************************************************************************** * void lcd_write_yuv_420_lines_odither(fb_data *dst, * unsigned char const * const src[3], * int width, * int stride, * int x_screen, * int y_screen); * * |R| |1.000000 -0.000001 1.402000| |Y'| * |G| = |1.000000 -0.334136 -0.714136| |Pb| * |B| |1.000000 1.772000 0.000000| |Pr| * Red scaled at twice g & b but at same precision to place it in correct * bit position after multiply and leave instruction count lower. * |R| |258 0 408| |Y' - 16| * |G| = |149 -49 -104| |Cb - 128| * |B| |149 258 0| |Cr - 128| * * Write four RGB565 pixels in the following order on each loop: * 1 3 + > down * 2 4 \/ left * * Kernel pattern (raw|rotated|use order): * 5 3 4 2 2 6 3 7 row0 row2 > down * 1 7 0 6 | 4 0 5 1 | 2 4 6 0 3 5 7 1 col0 left * 4 2 5 3 | 3 7 2 6 | 3 5 7 1 2 4 6 0 col2 \/ * 0 6 1 7 5 1 4 0 */ .section .icode, "ax", %progbits .align 2 .global lcd_write_yuv420_lines_odither .type lcd_write_yuv420_lines_odither, %function lcd_write_yuv420_lines_odither: @ r0 = dst @ r1 = yuv_src @ r2 = width @ r3 = stride @ [sp] = x_screen @ [sp+4] = y_screen stmfd sp!, { r4-r12, lr } @ save non-scratch ldmia r1, { r4, r5, r6 } @ r4 = yuv_src[0] = Y'_p @ r5 = yuv_src[1] = Cb_p @ r6 = yuv_src[2] = Cr_p @ sub r3, r3, #1 @ add r1, sp, #40 @ Line up pattern and kernel quadrant ldmia r1, { r12, r14 } @ eor r14, r14, r12 @ and r14, r14, #0x2 @ mov r14, r14, lsl #6 @ 0x00 or 0x80 10: @ loop line @ @ ldrb r7, [r4], #1 @ r7 = *Y'_p++; ldrb r8, [r5], #1 @ r8 = *Cb_p++; ldrb r9, [r6], #1 @ r9 = *Cr_p++; @ eor r14, r14, #0x80 @ flip pattern quadrant @ sub r7, r7, #16 @ r7 = Y = (Y' - 16)*149 add r12, r7, r7, asl #2 @ add r12, r12, r12, asl #4 @ add r7, r12, r7, asl #6 @ @ sub r8, r8, #128 @ Cb -= 128 sub r9, r9, #128 @ Cr -= 128 @ add r10, r8, r8, asl #4 @ r10 = guv = Cr*104 + Cb*49 add r10, r10, r8, asl #5 @ add r10, r10, r9, asl #3 @ add r10, r10, r9, asl #5 @ add r10, r10, r9, asl #6 @ @ mov r8, r8, asl #1 @ r8 = bu = Cb*258 add r8, r8, r8, asl #7 @ @ add r9, r9, r9, asl #1 @ r9 = rv = Cr*408 add r9, r9, r9, asl #4 @ mov r9, r9, asl #3 @ @ @ compute R, G, and B add r1, r8, r7 @ r1 = b' = Y + bu add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv rsb r7, r10, r7 @ r7 = g' = Y + guv @ @ r8 = bu, r9 = rv, r10 = guv @ sub r12, r1, r1, lsr #5 @ r1 = 31/32*b + b/256 add r1, r12, r1, lsr #8 @ @ sub r12, r11, r11, lsr #5 @ r11 = 31/32*r + r/256 add r11, r12, r11, lsr #8 @ @ sub r12, r7, r7, lsr #6 @ r7 = 63/64*g + g/256 add r7, r12, r7, lsr #8 @ @ add r12, r14, #0x100 @ @ add r1, r1, r12 @ b = r1 + delta add r11, r11, r12, lsl #1 @ r = r11 + delta*2 add r7, r7, r12, lsr #1 @ g = r7 + delta/2 @ orr r12, r1, r11, asr #1 @ check if clamping is needed... orr r12, r12, r7 @ ...at all movs r12, r12, asr #15 @ beq 15f @ no clamp @ movs r12, r1, asr #15 @ clamp b mvnne r1, r12, lsr #15 @ andne r1, r1, #0x7c00 @ mask b only if clamped movs r12, r11, asr #16 @ clamp r mvnne r11, r12, lsr #16 @ movs r12, r7, asr #15 @ clamp g mvnne r7, r12, lsr #15 @ 15: @ no clamp @ @ ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride) @ and r11, r11, #0xf800 @ pack pixel and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) | orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) | orr r1, r11, r1, lsr #10 @ (b >> 10) @ #if LCD_WIDTH >= LCD_HEIGHT strh r1, [r0] @ #elif LCD_WIDTH < 256 strh r1, [r0], #LCD_WIDTH @ store pixel #else strh r1, [r0] @ #endif @ sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149 add r12, r7, r7, asl #2 @ add r12, r12, r12, asl #4 @ add r7, r12, r7, asl #6 @ @ compute R, G, and B add r1, r8, r7 @ r1 = b' = Y + bu add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv rsb r7, r10, r7 @ r7 = g' = Y + guv @ sub r12, r1, r1, lsr #5 @ r1 = 31/32*b' + b'/256 add r1, r12, r1, lsr #8 @ @ sub r12, r11, r11, lsr #5 @ r11 = 31/32*r' + r'/256 add r11, r12, r11, lsr #8 @ @ sub r12, r7, r7, lsr #6 @ r7 = 63/64*g' + g'/256 add r7, r12, r7, lsr #8 @ @ add r12, r14, #0x200 @ @ add r1, r1, r12 @ b = r1 + delta add r11, r11, r12, lsl #1 @ r = r11 + delta*2 add r7, r7, r12, lsr #1 @ g = r7 + delta/2 @ orr r12, r1, r11, asr #1 @ check if clamping is needed... orr r12, r12, r7 @ ...at all movs r12, r12, asr #15 @ beq 15f @ no clamp @ movs r12, r1, asr #15 @ clamp b mvnne r1, r12, lsr #15 @ andne r1, r1, #0x7c00 @ mask b only if clamped movs r12, r11, asr #16 @ clamp r mvnne r11, r12, lsr #16 @ movs r12, r7, asr #15 @ clamp g mvnne r7, r12, lsr #15 @ 15: @ no clamp @ @ ldrb r12, [r4], #1 @ r12 = Y' = *(Y'_p++) @ and r11, r11, #0xf800 @ pack pixel and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) | orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) | orr r1, r11, r1, lsr #10 @ (b >> 10) @ #if LCD_WIDTH >= LCD_HEIGHT add r0, r0, #2*LCD_WIDTH @ strh r1, [r0] @ store pixel sub r0, r0, #2*LCD_WIDTH @ #elif LCD_WIDTH < 256 strh r1, [r0, #-LCD_WIDTH-2] @ store pixel #else strh r1, [r0, #-2] @ store pixel add r0, r0, #LCD_WIDTH @ #endif @ sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149 add r12, r7, r7, asl #2 @ add r12, r12, r12, asl #4 @ add r7, r12, r7, asl #6 @ @ compute R, G, and B add r1, r8, r7 @ r1 = b' = Y + bu add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv rsb r7, r10, r7 @ r7 = g' = Y + guv @ @ r8 = bu, r9 = rv, r10 = guv @ sub r12, r1, r1, lsr #5 @ r1 = 31/32*b' + b'/256 add r1, r12, r1, lsr #8 @ @ sub r12, r11, r11, lsr #5 @ r11 = 31/32*r' + r'/256 add r11, r12, r11, lsr #8 @ @ sub r12, r7, r7, lsr #6 @ r7 = 63/64*g' + g'/256 add r7, r12, r7, lsr #8 @ @ add r12, r14, #0x300 @ @ add r1, r1, r12 @ b = r1 + delta add r11, r11, r12, lsl #1 @ r = r11 + delta*2 add r7, r7, r12, lsr #1 @ g = r7 + delta/2 @ orr r12, r1, r11, asr #1 @ check if clamping is needed... orr r12, r12, r7 @ ...at all movs r12, r12, asr #15 @ beq 15f @ no clamp @ movs r12, r1, asr #15 @ clamp b mvnne r1, r12, lsr #15 @ andne r1, r1, #0x7c00 @ mask b only if clamped movs r12, r11, asr #16 @ clamp r mvnne r11, r12, lsr #16 @ movs r12, r7, asr #15 @ clamp g mvnne r7, r12, lsr #15 @ 15: @ no clamp @ @ ldrb r12, [r4, r3] @ r12 = Y' = *(Y'_p + stride) @ and r11, r11, #0xf800 @ pack pixel and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) | orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) | orr r1, r11, r1, lsr #10 @ (b >> 10) @ #if LCD_WIDTH >= LCD_HEIGHT strh r1, [r0, #2] #elif LCD_WIDTH < 256 strh r1, [r0, #LCD_WIDTH]! @ store pixel #else strh r1, [r0] @ #endif sub r7, r12, #16 @ r7 = Y = (Y' - 16)*149 add r12, r7, r7, asl #2 @ add r12, r12, r12, asl #4 @ add r7, r12, r7, asl #6 @ @ compute R, G, and B add r1, r8, r7 @ r1 = b' = Y + bu add r11, r9, r7, asl #1 @ r11 = r' = Y*2 + rv rsb r7, r10, r7 @ r7 = g' = Y + guv @ sub r12, r1, r1, lsr #5 @ r1 = 31/32*b + b/256 add r1, r12, r1, lsr #8 @ @ sub r12, r11, r11, lsr #5 @ r11 = 31/32*r + r/256 add r11, r12, r11, lsr #8 @ @ sub r12, r7, r7, lsr #6 @ r7 = 63/64*g + g/256 add r7, r12, r7, lsr #8 @ @ @ This element is zero - use r14 @ @ add r1, r1, r14 @ b = r1 + delta add r11, r11, r14, lsl #1 @ r = r11 + delta*2 add r7, r7, r14, lsr #1 @ g = r7 + delta/2 @ orr r12, r1, r11, asr #1 @ check if clamping is needed... orr r12, r12, r7 @ ...at all movs r12, r12, asr #15 @ beq 15f @ no clamp @ movs r12, r1, asr #15 @ clamp b mvnne r1, r12, lsr #15 @ andne r1, r1, #0x7c00 @ mask b only if clamped movs r12, r11, asr #16 @ clamp r mvnne r11, r12, lsr #16 @ movs r12, r7, asr #15 @ clamp g mvnne r7, r12, lsr #15 @ 15: @ no clamp @ @ and r11, r11, #0xf800 @ pack pixel and r7, r7, #0x7e00 @ r1 = pixel = (r & 0xf800) | orr r11, r11, r7, lsr #4 @ ((g & 0x7e00) >> 4) | orr r1, r11, r1, lsr #10 @ (b >> 10) @ #if LCD_WIDTH >= LCD_HEIGHT add r0, r0, #2*LCD_WIDTH strh r1, [r0, #2] @ store pixel #if LCD_WIDTH <= 512 sub r0, r0, #(2*LCD_WIDTH)-4 #else sub r0, r0, #(2*LCD_WIDTH) add r0, r0, #4 #endif #else strh r1, [r0, #-2] @ store pixel #if LCD_WIDTH < 256 add r0, r0, #2*LCD_WIDTH @ #else add r0, r0, #LCD_WIDTH @ #endif #endif @ subs r2, r2, #2 @ subtract block from width bgt 10b @ loop line @ @ ldmfd sp!, { r4-r12, pc } @ restore registers and return .ltorg @ dump constant pool .size lcd_write_yuv420_lines_odither, .-lcd_write_yuv420_lines_odither