/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2006 by Jens Arnold * * All files in this archive are subject to the GNU General Public License. * See the file COPYING in the source tree root for full license agreement. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "config.h" #include "cpu.h" .section .icode, "ax", @progbits /* lcd_write_yuv420_lines(), based on lcd-as-x5.S * * See http://en.wikipedia.org/wiki/YCbCr * ITU-R BT.601 (formerly CCIR 601): * |Y'| | 0.299000 0.587000 0.114000| |R| * |Pb| = |-0.168736 -0.331264 0.500000| |G| or 0.564334*(B - Y') * |Pr| | 0.500000 -0.418688 0.081312| |B| or 0.713267*(R - Y') * Scaled, normalized and rounded: * |Y'| | 65 129 25| |R| + 16 : 16->235 * |Cb| = |-38 -74 112| |G| + 128 : 16->240 * |Cr| |112 -94 -18| |B| + 128 : 16->240 * * The inverse: * |R| |1.000000 0.000000 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 RGB666, as converting * directly to RGB565 gives too much roundoff error: * |R| |74 0 101| |Y' - 16| / 256 * |G| = |74 -24 -51| |Cb - 128| / 256 * |B| |74 128 0| |Cr - 128| / 256 */ .align 2 .global lcd_write_yuv420_lines .type lcd_write_yuv420_lines, @function lcd_write_yuv420_lines: lea.l (-36, %sp), %sp /* free up some registers */ movem.l %d2-%d6/%a2-%a5, (%sp) lea.l 0xf0000002, %a0 /* LCD data port */ movem.l (36+4, %sp), %a1-%a5 /* Y data, Cb data, guv storage, Cr data, width */ lea.l (%a1, %a5), %a5 /* end address */ .yuv_line_loop1: /* chroma for first & second pixel */ clr.l %d1 /* load bu component */ move.b (%a2), %d1 clr.l %d3 /* load rv component */ move.b (%a4), %d3 moveq.l #-128, %d0 add.l %d0, %d1 add.l %d0, %d3 move.l %d1, %d2 /* %d2 = cb component for guv */ asr.l #1, %d1 /* %d1 = 128 * (Cb - 128) / 256 */ move.b %d1, (%a2)+ /* save bu for next line */ moveq.l #-24, %d0 muls.w %d0, %d2 /* %d2 = -24 * (Cb - 128)*/ moveq.l #-51, %d0 muls.w %d3, %d0 add.l %d0, %d2 /* %d2 = -24 * (Cb - 128) - 51 * (Cr - 128) */ asr.l #8, %d2 move.b %d2, (%a3)+ /* save guv for next line */ moveq.l #101, %d0 muls.w %d0, %d3 /* %d3 = 101 * (Cr - 128) */ asr.l #8, %d3 move.b %d3, (%a4)+ /* save rv for next line */ /* luma for first pixel */ clr.l %d4 /* load y component */ move.b (%a1)+, %d4 moveq.l #74, %d0 muls.w %d0, %d4 /* %d4 = 36 * Y */ asr.l #8, %d4 subq.l #4, %d4 /* correction for (Y - 16) and rounding */ move.l %d4, %d5 move.l %d4, %d6 /* combine & write first pixel */ add.l %d1, %d4 /* %d4 = blue */ add.l %d2, %d5 /* %d5 = green */ add.l %d3, %d6 /* %d6 = red */ move.l %d4, %d0 /* clamping */ or.l %d5, %d0 or.l %d6, %d0 asr.l #6, %d0 beq.s .yuv_all_ok1 moveq.l #63, %d0 cmp.l %d0, %d4 bls.s .yuv_blue_ok1 spl.b %d4 and.l %d0, %d4 .yuv_blue_ok1: cmp.l %d0, %d5 bls.s .yuv_green_ok1 spl.b %d5 and.l %d0, %d5 .yuv_green_ok1: cmp.l %d0, %d6 bls.s .yuv_red_ok1 spl.b %d6 and.l %d0, %d6 .yuv_red_ok1: .yuv_all_ok1: lsr.l #1, %d6 /* pack, convert to RGB565 and output */ lsr.l #1, %d4 lsl.l #6, %d6 or.l %d6, %d5 lsl.l #5, %d5 or.l %d5, %d4 move.w %d4, (%a0) /* luma for second pixel */ clr.l %d4 /* load y component */ move.b (%a1)+, %d4 moveq.l #74, %d0 muls.w %d0, %d4 /* %d4 = 36 * Y */ asr.l #8, %d4 subq.l #4, %d4 /* correction for (Y - 16) and rounding */ /* combine & write second pixel */ add.l %d4, %d1 /* %d1 = blue */ add.l %d4, %d2 /* %d2 = green */ add.l %d4, %d3 /* %d3 = red */ move.l %d1, %d0 /* clamping */ or.l %d2, %d0 or.l %d3, %d0 asr.l #6, %d0 beq.s .yuv_all_ok2 moveq.l #63, %d0 cmp.l %d0, %d1 bls.s .yuv_blue_ok2 spl.b %d1 and.l %d0, %d1 .yuv_blue_ok2: cmp.l %d0, %d2 bls.s .yuv_green_ok2 spl.b %d2 and.l %d0, %d2 .yuv_green_ok2: cmp.l %d0, %d3 bls.s .yuv_red_ok2 spl.b %d3 and.l %d0, %d3 .yuv_red_ok2: .yuv_all_ok2: lsr.l #1, %d3 /* pack, convert to RGB565 and output */ lsr.l #1, %d1 lsl.l #6, %d3 or.l %d3, %d2 lsl.l #5, %d2 or.l %d2, %d1 move.w %d1, (%a0) cmp.l %a1,%a5 /* run %a1 up to end of line */ bhi.w .yuv_line_loop1 /* Rewind chroma pointers */ movem.l (36+8, %sp), %a2-%a5 /* bu data, guv data, rv data, width */ lea.l (%a1, %a5), %a5 /* next end address */ .yuv_line_loop2: /* read saved chromas and sign extend */ move.b (%a2)+, %d1 extb.l %d1 move.b (%a3)+, %d2 extb.l %d2 move.b (%a4)+, %d3 extb.l %d3 /* luma for first pixel */ clr.l %d4 /* load y component */ move.b (%a1)+, %d4 moveq.l #74, %d0 muls.w %d0, %d4 /* %d4 = 36 * Y */ asr.l #8, %d4 subq.l #4, %d4 /* correction for (Y - 16) and rounding */ move.l %d4, %d5 move.l %d4, %d6 /* combine & write first pixel */ add.l %d1, %d4 /* %d4 = blue */ add.l %d2, %d5 /* %d5 = green */ add.l %d3, %d6 /* %d6 = red */ move.l %d4, %d0 /* clamping */ or.l %d5, %d0 or.l %d6, %d0 asr.l #6, %d0 beq.s .yuv_all_ok3 moveq.l #63, %d0 cmp.l %d0, %d4 bls.s .yuv_blue_ok3 spl.b %d4 and.l %d0, %d4 .yuv_blue_ok3: cmp.l %d0, %d5 bls.s .yuv_green_ok3 spl.b %d5 and.l %d0, %d5 .yuv_green_ok3: cmp.l %d0, %d6 bls.s .yuv_red_ok3 spl.b %d6 and.l %d0, %d6 .yuv_red_ok3: .yuv_all_ok3: lsr.l #1, %d6 /* pack, convert to RGB565 and output */ lsr.l #1, %d4 lsl.l #6, %d6 or.l %d6, %d5 lsl.l #5, %d5 or.l %d5, %d4 move.w %d4, (%a0) /* luma for second pixel */ clr.l %d4 /* load y component */ move.b (%a1)+, %d4 moveq.l #74, %d0 muls.w %d0, %d4 /* %d4 = 36 * Y */ asr.l #8, %d4 subq.l #4, %d4 /* correction for (Y - 16) and rounding */ /* combine & write second pixel */ add.l %d4, %d1 /* %d1 = blue */ add.l %d4, %d2 /* %d2 = green */ add.l %d4, %d3 /* %d3 = red */ move.l %d1, %d0 /* clamping */ or.l %d2, %d0 or.l %d3, %d0 asr.l #6, %d0 beq.s .yuv_all_ok4 moveq.l #63, %d0 cmp.l %d0, %d1 bls.s .yuv_blue_ok4 spl.b %d1 and.l %d0, %d1 .yuv_blue_ok4: cmp.l %d0, %d2 bls.s .yuv_green_ok4 spl.b %d2 and.l %d0, %d2 .yuv_green_ok4: cmp.l %d0, %d3 bls.s .yuv_red_ok4 spl.b %d3 and.l %d0, %d3 .yuv_red_ok4: .yuv_all_ok4: lsr.l #1, %d3 /* pack, convert to RGB565 and output */ lsr.l #1, %d1 lsl.l #6, %d3 or.l %d3, %d2 lsl.l #5, %d2 or.l %d2, %d1 move.w %d1, (%a0) cmp.l %a1, %a5 /* run %a1 up to end of line */ bhi.w .yuv_line_loop2 movem.l (%sp), %d2-%d6/%a2-%a5 lea.l (36, %sp), %sp /* restore registers */ rts .lcd_write_yuv420_lines_end: .size lcd_write_yuv420_lines, .lcd_write_yuv420_lines_end - lcd_write_yuv420_lines