| /*************************************************************************** |
| * __________ __ ___. |
| * Open \______ \ ____ ____ | | _\_ |__ _______ ___ |
| * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / |
| * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < |
| * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ |
| * \/ \/ \/ \/ \/ |
| * $Id$ |
| * |
| * Copyright (C) 2006 by Jens Arnold |
| * |
| * 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" |
| |
| .section .icode, "ax", @progbits |
| |
| /* lcd_write_yuv420_lines() |
| * |
| * 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 RGB565: |
| * |R| |19611723 0 26881894| |Y' - 16| >> 27 |
| * |G| = |19611723 -6406711 -13692816| |Cb - 128| >> 26 |
| * |B| |19611723 33976259 0| |Cr - 128| >> 27 |
| * |
| * Needs EMAC set to saturated, signed integer mode. |
| * |
| * register usage: |
| * %a0 - LCD data port |
| * %a1 - Y pointer |
| * %a2 - C pointer |
| * %a3 - C width |
| * %a4 - Y end address |
| * %a5 - Y factor |
| * %a6 - BU factor |
| * %d0 - scratch |
| * %d1 - B, previous Y \ alternating |
| * %d2 - U / B, previous Y / |
| * %d3 - V / G |
| * %d4 - R / output pixel |
| * %d5 - GU factor |
| * %d6 - GV factor |
| * %d7 - RGB signed -> unsigned conversion mask |
| */ |
| .align 2 |
| .global lcd_write_yuv420_lines |
| .type lcd_write_yuv420_lines, @function |
| |
| lcd_write_yuv420_lines: |
| lea.l (-44, %sp), %sp /* free up some registers */ |
| movem.l %d2-%d7/%a2-%a6, (%sp) |
| |
| lea.l 0xf0000002, %a0 /* LCD data port */ |
| movem.l (44+4, %sp), %a1-%a3 /* Y data, C data, C width */ |
| lea.l (%a1, %a3*2), %a4 /* Y end address */ |
| |
| move.l #19611723, %a5 /* y factor */ |
| move.l #33976259, %a6 /* bu factor */ |
| move.l #-6406711, %d5 /* gu factor */ |
| move.l #-13692816, %d6 /* gv factor */ |
| move.l #0x8410, %d7 /* bitmask for signed->unsigned conversion |
| * of R, G and B within RGB565 at once */ |
| |
| /* chroma for first 2x2 pixel block */ |
| clr.l %d3 /* load v component */ |
| move.b (%a2, %a3), %d3 |
| clr.l %d2 /* load u component */ |
| move.b (%a2)+, %d2 |
| moveq.l #-128, %d0 |
| add.l %d0, %d2 |
| add.l %d0, %d3 |
| |
| mac.l %a6, %d2, %acc0 /* bu */ |
| mac.l %d5, %d2, %acc1 /* gu */ |
| mac.l %d6, %d3, %acc1 /* gv */ |
| move.l #26881894, %d0 /* rv factor */ |
| mac.l %d0, %d3, %acc2 /* rv */ |
| |
| /* luma for very first pixel (top left) */ |
| clr.l %d1 |
| move.b (%a1, %a3*2), %d1 |
| moveq.l #-126, %d0 |
| add.l %d1, %d0 /* y' (-0.5 ... +0.5) */ |
| mac.l %a5, %d0, %acc0 |
| mac.l %a5, %d0, %acc1 |
| mac.l %a5, %d0, %acc2 |
| |
| bra.b .yuv_line_entry |
| |
| .yuv_line_loop: |
| /* chroma for 2x2 pixel block */ |
| clr.l %d3 /* load v component */ |
| move.b (%a2, %a3), %d3 |
| clr.l %d2 /* load u component */ |
| move.b (%a2)+, %d2 |
| moveq.l #-128, %d0 |
| add.l %d0, %d2 |
| add.l %d0, %d3 |
| |
| mac.l %a6, %d2, %acc0 /* bu */ |
| mac.l %d5, %d2, %acc1 /* gu */ |
| mac.l %d6, %d3, %acc1 /* gv */ |
| move.l #26881894, %d0 /* rv factor */ |
| mac.l %d0, %d3, %acc2 /* rv */ |
| |
| /* luma for first pixel (top left) */ |
| clr.l %d1 |
| move.b (%a1, %a3*2), %d1 |
| moveq.l #-126, %d0 |
| add.l %d1, %d0 /* y' (-0.5 ... +0.5) */ |
| mac.l %a5, %d0, %acc0 |
| mac.l %a5, %d0, %acc1 |
| mac.l %a5, %d0, %acc2 |
| |
| move.w %d4, (%a0) |
| /* LCD write is delayed one pixel to use it for filling the EMAC latency */ |
| |
| /* convert to RGB565, pack and output */ |
| .yuv_line_entry: |
| moveq.l #27, %d0 |
| move.l %acc0, %d2 |
| move.l %acc1, %d3 |
| move.l %acc2, %d4 |
| lsr.l %d0, %d2 |
| lsr.l %d0, %d4 |
| moveq.l #26, %d0 |
| lsr.l %d0, %d3 |
| lsl.l #6, %d4 |
| or.l %d3, %d4 |
| lsl.l #5, %d4 |
| or.l %d2, %d4 |
| eor.l %d7, %d4 |
| |
| /* luma for second pixel (bottom left) as delta from the first */ |
| clr.l %d2 |
| move.b (%a1)+, %d2 |
| move.l %d2, %d0 |
| sub.l %d1, %d0 |
| mac.l %a5, %d0, %acc0 |
| mac.l %a5, %d0, %acc1 |
| mac.l %a5, %d0, %acc2 |
| |
| move.w %d4, (%a0) |
| /* LCD write is delayed one pixel to use it for filling the EMAC latency */ |
| |
| /* convert to RGB565, pack and output */ |
| moveq.l #27, %d0 |
| move.l %acc0, %d1 |
| move.l %acc1, %d3 |
| move.l %acc2, %d4 |
| lsr.l %d0, %d1 |
| lsr.l %d0, %d4 |
| moveq.l #26, %d0 |
| lsr.l %d0, %d3 |
| lsl.l #6, %d4 |
| or.l %d3, %d4 |
| lsl.l #5, %d4 |
| or.l %d1, %d4 |
| eor.l %d7, %d4 |
| |
| /* luma for third pixel (top right) as delta from the second */ |
| clr.l %d1 |
| move.b (%a1, %a3*2), %d1 |
| move.l %d1, %d0 |
| sub.l %d2, %d0 |
| mac.l %a5, %d0, %acc0 |
| mac.l %a5, %d0, %acc1 |
| mac.l %a5, %d0, %acc2 |
| |
| move.w %d4, (%a0) |
| /* LCD write is delayed one pixel to use it for filling the EMAC latency */ |
| |
| /* convert to RGB565, pack and output */ |
| moveq.l #27, %d0 |
| move.l %acc0, %d2 |
| move.l %acc1, %d3 |
| move.l %acc2, %d4 |
| lsr.l %d0, %d2 |
| lsr.l %d0, %d4 |
| moveq.l #26, %d0 |
| lsr.l %d0, %d3 |
| lsl.l #6, %d4 |
| or.l %d3, %d4 |
| lsl.l #5, %d4 |
| or.l %d2, %d4 |
| eor.l %d7, %d4 |
| |
| /* luma for fourth pixel (bottom right) as delta from the third */ |
| clr.l %d2 |
| move.b (%a1)+, %d2 |
| move.l %d2, %d0 |
| sub.l %d1, %d0 |
| mac.l %a5, %d0, %acc0 |
| mac.l %a5, %d0, %acc1 |
| mac.l %a5, %d0, %acc2 |
| |
| move.w %d4, (%a0) |
| /* LCD write is delayed one pixel to use it for filling the EMAC latency */ |
| |
| /* convert to RGB565, pack and output */ |
| moveq.l #27, %d0 |
| movclr.l %acc0, %d1 |
| movclr.l %acc1, %d3 |
| movclr.l %acc2, %d4 |
| lsr.l %d0, %d1 |
| lsr.l %d0, %d4 |
| moveq.l #26, %d0 |
| lsr.l %d0, %d3 |
| lsl.l #6, %d4 |
| or.l %d3, %d4 |
| lsl.l #5, %d4 |
| or.l %d1, %d4 |
| eor.l %d7, %d4 |
| |
| cmp.l %a1, %a4 /* run %a1 up to end of line */ |
| bhi.w .yuv_line_loop |
| |
| move.w %d4, (%a0) /* write (very) last pixel */ |
| |
| movem.l (%sp), %d2-%d7/%a2-%a6 |
| lea.l (44, %sp), %sp /* restore registers */ |
| rts |
| .yuv_end: |
| .size lcd_write_yuv420_lines, .yuv_end - lcd_write_yuv420_lines |