/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * * Copyright (C) 2010-2011 by Andree Buschmann * * Generic asm helper function used by YUV blitting. * * 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" /**************************************************************************** * #define FORCE_FIFO_WAIT * * This is not needed in YUV blitting when the LCD IF is fast enough. In this * case YUV-to-RGB conversion per pixel needs longer than the transfer of a * pixel via the LCD IF. ****************************************************************************/ #include "config.h" /* Set FIFO wait for both iPod Color and iPod nano1G until we know for which * devices we can switch this off. */ #define FORCE_FIFO_WAIT .section .icode, "ax", %progbits /**************************************************************************** * extern void lcd_write_yuv420_lines(unsigned char const * const src[3], * const unsigned LCD_BASE, * int width, * int stride); * * Conversion from Motion JPEG and MPEG Y'PbPr to RGB is: * |R| |1.164 0.000 1.596| |Y' - 16| * |G| = |1.164 -0.391 -0.813| |Pb - 128| * |B| |1.164 2.018 0.000| |Pr - 128| * * 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 * * Converts two lines from YUV to RGB565 and writes to LCD at once. First loop * loads Cb/Cr, calculates the chroma offset and saves them to buffer. Within * the second loop these chroma offset are reloaded from buffer. Within each * loop two pixels are calculated and written to LCD. */ .align 2 .global lcd_write_yuv420_lines .type lcd_write_yuv420_lines, %function lcd_write_yuv420_lines: /* r0 = src = yuv_src */ /* r1 = dst = LCD_BASE */ /* r2 = width */ /* r3 = stride */ stmfd sp!, { r4-r10, lr } /* save non-scratch */ ldmia r0, { r9, r10, r12 } /* r9 = yuv_src[0] = Y'_p */ /* r10 = yuv_src[1] = Cb_p */ /* r12 = yuv_src[2] = Cr_p */ add r3, r9, r3 /* r3 = &ysrc[stride] */ add r4, r2, r2, asr #1 /* chroma buffer lenght = width/2 *3 */ mov r4, r4, asl #2 /* use words for str/ldm possibility */ add r4, r4, #19 /* plus room for 4 additional words, */ bic r4, r4, #3 /* rounded up to multiples of 4 byte */ sub sp, sp, r4 /* and allocate on stack */ stmia sp, {r1-r4} /* LCD_BASE, width, &ysrc[stride], stack_alloc */ mov r7, r2 /* r7 = loop count */ add r8, sp, #16 /* chroma buffer */ add lr, r1, #0x100 /* LCD data port = LCD2_BASE + 0x100 */ /* 1st loop start */ 10: /* loop start */ ldrb r0, [r10], #1 /* r0 = *usrc++ = *Cb_p++ */ ldrb r1, [r12], #1 /* r1 = *vsrc++ = *Cr_p++ */ sub r0, r0, #128 /* r0 = Cb-128 */ sub r1, r1, #128 /* r1 = Cr-128 */ add r2, r1, r1, asl #1 /* r2 = Cr*51 + Cb*24 */ add r2, r2, r2, asl #4 add r2, r2, r0, asl #3 add r2, r2, r0, asl #4 add r4, r1, r1, asl #2 /* r1 = Cr*101 */ add r4, r4, r1, asl #5 add r1, r4, r1, asl #6 add r1, r1, #256 /* r1 = rv = (r1 + 256) >> 9 */ mov r1, r1, asr #9 rsb r2, r2, #128 /* r2 = guv = (-r2 + 128) >> 8 */ mov r2, r2, asr #8 add r0, r0, #2 /* r0 = bu = (Cb*128 + 256) >> 9 */ mov r0, r0, asr #2 stmia r8!, {r0-r2} /* store r0, r1 and r2 to chroma buffer */ /* 1st loop, first pixel */ ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */ sub r5, r5, #16 /* r5 = (Y'-16) * 74 */ add r3, r5, r5, asl #2 add r5, r3, r5, asl #5 add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */ add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */ add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */ orr r5, r6, r4 /* check if clamping is needed... */ orr r5, r5, r3, asr #1 /* ...at all */ cmp r5, #31 bls 15f /* -> no clamp */ cmp r6, #31 /* clamp r */ mvnhi r6, r6, asr #31 andhi r6, r6, #31 cmp r3, #63 /* clamp g */ mvnhi r3, r3, asr #31 andhi r3, r3, #63 cmp r4, #31 /* clamp b */ mvnhi r4, r4, asr #31 andhi r4, r4, #31 15: /* no clamp */ /* calculate pixel_1 and save to r4 for later pixel packing */ orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */ orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */ /* 1st loop, second pixel */ ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */ sub r5, r5, #16 /* r5 = (Y'-16) * 74 */ add r3, r5, r5, asl #2 add r5, r3, r5, asl #5 add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */ add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */ add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */ orr r0, r6, r5 /* check if clamping is needed... */ orr r0, r0, r3, asr #1 /* ...at all */ cmp r0, #31 bls 15f /* -> no clamp */ cmp r6, #31 /* clamp r */ mvnhi r6, r6, asr #31 andhi r6, r6, #31 cmp r3, #63 /* clamp g */ mvnhi r3, r3, asr #31 andhi r3, r3, #63 cmp r5, #31 /* clamp b */ mvnhi r5, r5, asr #31 andhi r5, r5, #31 15: /* no clamp */ /* calculate pixel_2 and pack with pixel_1 before writing */ orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */ orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */ #ifdef FORCE_FIFO_WAIT /* wait for FIFO half full */ .fifo_wait1: ldr r3, [lr, #-0xE0] /* while !(LCD2_BLOCK_CTRL & 0x1000000); */ tst r3, #0x1000000 beq .fifo_wait1 #endif mov r3, r4, lsl #8 /* swap pixel_1 */ and r3, r3, #0xff00 add r4, r3, r4, lsr #8 orr r4, r4, r5, lsl #24 /* swap pixel_2 and pack with pixel_1 */ mov r5, r5, lsr #8 orr r4, r4, r5, lsl #16 str r4, [lr] /* write pixel_1 and pixel_2 */ subs r7, r7, #2 /* check for loop end */ bgt 10b /* back to beginning */ /* 1st loop end */ /* Reload several registers for pointer rewinding for next loop */ add r8, sp, #16 /* chroma buffer */ ldmia sp, { r1, r7, r9} /* r1 = LCD_BASE */ /* r7 = loop count */ /* r9 = &ysrc[stride] */ /* 2nd loop start */ 20: /* loop start */ /* restore r0 (bu), r1 (rv) and r2 (guv) from chroma buffer */ ldmia r8!, {r0-r2} /* 2nd loop, first pixel */ ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */ sub r5, r5, #16 /* r5 = (Y'-16) * 74 */ add r3, r5, r5, asl #2 add r5, r3, r5, asl #5 add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */ add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */ add r4, r0, r5, asr #8 /* r4 = b = (Y >> 9) + bu */ orr r5, r6, r4 /* check if clamping is needed... */ orr r5, r5, r3, asr #1 /* ...at all */ cmp r5, #31 bls 15f /* -> no clamp */ cmp r6, #31 /* clamp r */ mvnhi r6, r6, asr #31 andhi r6, r6, #31 cmp r3, #63 /* clamp g */ mvnhi r3, r3, asr #31 andhi r3, r3, #63 cmp r4, #31 /* clamp b */ mvnhi r4, r4, asr #31 andhi r4, r4, #31 15: /* no clamp */ /* calculate pixel_1 and save to r4 for later pixel packing */ orr r4, r4, r3, lsl #5 /* pixel_1 = r<<11 | g<<5 | b */ orr r4, r4, r6, lsl #11 /* r4 = pixel_1 */ /* 2nd loop, second pixel */ ldrb r5, [r9], #1 /* r5 = *ysrc++ = *Y'_p++ */ sub r5, r5, #16 /* r5 = (Y'-16) * 74 */ add r3, r5, r5, asl #2 add r5, r3, r5, asl #5 add r6, r1, r5, asr #8 /* r6 = r = (Y >> 9) + rv */ add r3, r2, r5, asr #7 /* r3 = g = (Y >> 8) + guv */ add r5, r0, r5, asr #8 /* r5 = b = (Y >> 9) + bu */ orr r0, r6, r5 /* check if clamping is needed... */ orr r0, r0, r3, asr #1 /* ...at all */ cmp r0, #31 bls 15f /* -> no clamp */ cmp r6, #31 /* clamp r */ mvnhi r6, r6, asr #31 andhi r6, r6, #31 cmp r3, #63 /* clamp g */ mvnhi r3, r3, asr #31 andhi r3, r3, #63 cmp r5, #31 /* clamp b */ mvnhi r5, r5, asr #31 andhi r5, r5, #31 15: /* no clamp */ /* calculate pixel_2 and pack with pixel_1 before writing */ orr r5, r5, r3, lsl #5 /* pixel_2 = r<<11 | g<<5 | b */ orr r5, r5, r6, lsl #11 /* r5 = pixel_2 */ #ifdef FORCE_FIFO_WAIT /* wait for FIFO half full */ .fifo_wait2: ldr r3, [lr, #-0xE0] /* while !(LCD2_BLOCK_CTRL & 0x1000000); */ tst r3, #0x1000000 beq .fifo_wait2 #endif mov r3, r4, lsl #8 /* swap pixel_1 */ and r3, r3, #0xff00 add r4, r3, r4, lsr #8 orr r4, r4, r5, lsl #24 /* swap pixel_2 and pack with pixel_1 */ mov r5, r5, lsr #8 orr r4, r4, r5, lsl #16 str r4, [lr] /* write pixel_1 and pixel_2 */ subs r7, r7, #2 /* check for loop end */ bgt 20b /* back to beginning */ /* 2nd loop end */ ldr r3, [sp, #12] add sp, sp, r3 /* deallocate buffer */ ldmpc regs=r4-r10 /* restore registers */ .ltorg .size lcd_write_yuv420_lines, .-lcd_write_yuv420_lines