/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2006 by Michael Sevakis
 * Based on lcd_write_data for H300 in lcd.S
 *
 * 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

/* begin 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 -0.000001  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 666:
 *   |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   0xf0008002,%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:
    /** Write first pixel **/
    clr.l   %d1             /* get bu component */
    move.b  (%a2),%d1
    clr.l   %d3             /* get 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        /* multiply first term of guv */
    muls.w  %d0,%d2
    moveq.l #-51,%d0        /* multiply second term of guv */
    muls.w  %d3,%d0
    add.l   %d0,%d2
    asr.l   #8,%d2
    move.b  %d2,(%a3)+      /* save guv for next line */
    moveq.l  #101,%d0
    muls.w  %d0,%d3
    asr.l   #8,%d3
    move.b  %d3,(%a4)+      /* save rv for next line */

    clr.l   %d4             /* get y component */
    move.b  (%a1)+,%d4
    moveq.l #74,%d0
    muls.w  %d0,%d4
    asr.l   #8,%d4
    subq.l  #4,%d4
    move.l  %d4,%d5
    move.l  %d4,%d6
    /* : %d4,%d5,%d6 = Y, %d1 = bu, %d2 = guv, %d3 = rv */

    add.l   %d3,%d4         /* get r */
    add.l   %d2,%d5         /* get g */
    add.l   %d1,%d6         /* get b */

    move.l  %d6,%d0         /* is clamping needed? */
    or.l    %d5,%d0
    or.l    %d4,%d0
    asr.l   #6,%d0
    beq.b   .yuv_no_clamp1  /* values in range: skip clamping */
    moveq.l #63, %d0
    cmp.l   %d0, %d4
    bls.s   .yuv_red_ok1
    spl.b   %d4
    and.l   %d0, %d4
.yuv_red_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_blue_ok1
    spl.b   %d6
    and.l   %d0, %d6
.yuv_blue_ok1:
.yuv_no_clamp1:
    /* : %d4 = R, %d5 = G, %d6 = B */

    move.l  %d5,%d0         /* save g for lower 9 bits */
    lsl.l   #3,%d4          /* R << 3 */
    lsr.l   #3,%d0          /* G >> 3 */
    or.l    %d4,%d0
    move.w  %d0,(%a0)       /* |00000000|000000000|0000000r|rrrrrggg| */
    lsl.l   #6,%d5          /* B << 6 */
    or.l    %d5,%d6         /* |00000000|000000000|0000gggg|ggbbbbbb| */
    move.w  %d6,(%a0)

    /** Write second pixel **/
    clr.l   %d4
    move.b  (%a1)+,%d4      /* get y component */
    moveq.l #74,%d0
    muls.w  %d0,%d4
    asr.l   #8,%d4
    subq.l  #4,%d4
    /* : %d4 = Y, %d1 = bu, %d2 = guv, %d3 = rv */

    /* Add Y + each chroma component (can clobber %d1-%d3 values now) */
    add.l   %d4,%d3         /* get r */
    add.l   %d4,%d2         /* get g */
    add.l   %d4,%d1         /* get b */

    move.l  %d1,%d0         /* is clamping needed? */
    or.l    %d2,%d0
    or.l    %d3,%d0
    asr.l   #6,%d0
    beq.b   .yuv_no_clamp2  /* values in range: skip clamping */
    moveq.l #63, %d0
    cmp.l   %d0, %d3
    bls.s   .yuv_red_ok2
    spl.b   %d3
    and.l   %d0, %d3
.yuv_red_ok2:
    cmp.l   %d0, %d2
    bls.s   .yuv_green_ok2
    spl.b   %d2
    and.l   %d0, %d2
.yuv_green_ok2:
    cmp.l   %d0, %d1
    bls.s   .yuv_blue_ok2
    spl.b   %d1
    and.l   %d0, %d1
.yuv_blue_ok2:
.yuv_no_clamp2:
    /* : %d3 = R, %d2 = G, %d1 = B */

    move.l  %d2,%d0         /* save g for lower 9 bits */
    lsl.l   #3,%d3          /* R << 3 */
    lsr.l   #3,%d0          /* G >> 3 */
    or.l    %d3,%d0         /* |00000000|000000000|0000000r|rrrrrggg| */
    move.w  %d0,(%a0)
    lsl.l   #6,%d2          /* G << 6 */
    or.l    %d2,%d1         /* |00000000|000000000|0000gggg|ggbbbbbb| */
    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:
    move.b  (%a2)+,%d1      /* read save chromas and sign extend */
    extb.l  %d1
    move.b  (%a3)+,%d2
    extb.l  %d2
    move.b  (%a4)+,%d3
    extb.l  %d3

    clr.l   %d4
    move.b  (%a1)+,%d4      /* get y component */
    moveq.l #74,%d0
    muls.w  %d0,%d4
    asr.l   #8,%d4
    subq.l  #4,%d4
    move.l  %d4,%d5
    move.l  %d4,%d6
    /* : %d4,%d5,%d6 = Y, %d1 = bu, %d2 = guv, %d3 = rv */

    add.l   %d3,%d4         /* get r */
    add.l   %d2,%d5         /* get g */
    add.l   %d1,%d6         /* get b */

    move.l  %d6,%d0         /* is clamping needed? */
    or.l    %d5,%d0
    or.l    %d4,%d0
    asr.l   #6,%d0
    beq.b   .yuv_no_clamp3  /* values in range: skip clamping */
    moveq.l #63, %d0
    cmp.l   %d0, %d4
    bls.s   .yuv_red_ok3
    spl.b   %d4
    and.l   %d0, %d4
.yuv_red_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_blue_ok3
    spl.b   %d6
    and.l   %d0, %d6
.yuv_blue_ok3:
.yuv_no_clamp3:
    /* : %d4 = R, %d5 = G, %d6 = B */

    move.l  %d5,%d0         /* save g for lower 9 bits */
    lsl.l   #3,%d4          /* R << 3 */
    lsr.l   #3,%d0          /* G >> 3 */
    or.l    %d4,%d0
    move.w  %d0,(%a0)       /* |00000000|000000000|0000000r|rrrrrggg| */
    lsl.l   #6,%d5          /* B << 6 */
    or.l    %d5,%d6         /* |00000000|000000000|0000gggg|ggbbbbbb| */
    move.w  %d6,(%a0)

    /** Write second pixel **/
    clr.l   %d4
    move.b  (%a1)+,%d4      /* get y component */
    moveq.l #74,%d0
    muls.w  %d0,%d4
    asr.l   #8,%d4
    subq.l  #4,%d4
    /* : %d4 = Y, %d1 = bu, %d2 = guv, %d3 = rv */

    /* Add Y + each chroma component (can clobber %d1-%d3 values now) */
    add.l   %d4,%d3         /* get r */
    add.l   %d4,%d2         /* get g */
    add.l   %d4,%d1         /* get b */

    move.l  %d1,%d0         /* is clamping needed? */
    or.l    %d2,%d0
    or.l    %d3,%d0
    asr.l   #6,%d0
    beq.b   .yuv_no_clamp4  /* values in range: skip clamping */
    moveq.l #63, %d0
    cmp.l   %d0, %d3
    bls.s   .yuv_red_ok4
    spl.b   %d3
    and.l   %d0, %d3
.yuv_red_ok4:
    cmp.l   %d0, %d2
    bls.s   .yuv_green_ok4
    spl.b   %d2
    and.l   %d0, %d2
.yuv_green_ok4:
    cmp.l   %d0, %d1
    bls.s   .yuv_blue_ok4
    spl.b   %d1
    and.l   %d0, %d1
.yuv_blue_ok4:
.yuv_no_clamp4:
    /* : %d3 = R, %d2 = G, %d1 = B */

    move.l  %d2,%d0         /* save g for lower 9 bits */
    lsl.l   #3,%d3          /* R << 3 */
    lsr.l   #3,%d0          /* G >> 3 */
    or.l    %d3,%d0         /* |00000000|000000000|0000000r|rrrrrggg| */
    move.w  %d0,(%a0)
    lsl.l   #6,%d2          /* G << 6 */
    or.l    %d2,%d1         /* |00000000|000000000|0000gggg|ggbbbbbb| */
    move.w  %d1,(%a0)

    cmp.l   %a1,%a5         /* run %a0 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

.yuv_end:
    .size   lcd_write_yuv420_lines,.yuv_end-lcd_write_yuv420_lines
/* end lcd_write_yuv420_lines */


/* begin lcd_write_data */
    .align      2
    .global     lcd_write_data
    .type       lcd_write_data,@function
lcd_write_data:
    move.l  (4,%sp),%a0     /* data pointer */
    move.l  (8,%sp),%d0     /* length in words */
    add.l   %d0,%d0         /* words -> bytes */
    add.l   %a0,%d0         /* -> end address */
    lea.l   0xf0008002,%a1  /* LCD data port */

    lea.l   (-20,%sp),%sp   /* free up some registers */
    movem.l %d2-%d5/%a2,(%sp)

    move.l  %a0,%d1
    btst.l  #1,%d1          /* already longword aligned? */
    beq.b   .wd_wordl_end   /* yes: skip initial word copy */
                            /* transfer initial word */
    move.w  (%a0)+,%d2      /* |????????|????????|rrrrrggg|gggbbbbb| */
    move.l  %d2,%d1
    lsr.l   #7,%d1          /* |0000000?|????????|???????r|rrrrgggg| */
    move.w  %d1,(%a1)       /*                           ^ ^^^^^^^   */
    lsl.l   #1,%d2          /* |????????|???????r|rrrrgggg|ggbbbbb0| */
    move.w  %d2,(%a1)       /*                           ^ ^^^^^^^   */

.wd_wordl_end:              /* now longword aligned */
    moveq.l #28,%d1
    add.l   %a0,%d1
    and.l   #0xFFFFFFF0,%d1 /* %d1 = second line bound */
    cmp.l   %d1,%d0         /* at least one full line to send? */
    blo.w   .wd_long2_start /* no: skip to trailing longword handling */

    subq.l  #8,%d1
    subq.l  #8,%d1          /* %d1 = first line bound */

    cmp.l   %a0,%d1         /* any leading longwords? */
    bls.b   .wd_long1_end   /* no: skip leading long loop */

.wd_long1_loop:
    move.l  (%a0)+,%d2      /* read longword */
    swap    %d2             /* |rrrrrggg|gggbbbbb|RRRRRGGG|GGGBBBBB| */
    move.l  %d2,%d5
    lsr.l   #7,%d5          /* |0000000r|rrrrgggg|ggbbbbbR|RRRRGGGG| */
    move.w  %d5,(%a1)       /*                           ^ ^^^^^^^   */
    lsl.l   #1,%d2          /* |rrrrgggg|ggbbbbbR|RRRRGGGG|GGBBBBB0| */
    move.w  %d2,(%a1)       /*                           ^ ^^^^^^^   */
    swap    %d5             /* |ggbbbbbR|RRRRGGGG|0000000r|rrrrgggg| */
    move.w  %d5,(%a1)       /*                           ^ ^^^^^^^   */
    swap    %d2             /* |RRRRBGGG|GGBBBBB0|rrrrgggg|ggbbbbbR| */
    move.w  %d2,(%a1)       /*                           ^ ^^^^^^^   */
    cmp.l   %a0,%d1
    bhi.b   .wd_long1_loop

.wd_long1_end:
    move.l  %d0,%a2
    lea.l   (-14,%a2),%a2

.wd_line_loop:
    movem.l (%a0),%d1-%d4   /* burst-read eight words */
    lea.l   (16,%a0),%a0    /* increment address */

    /* transfer four pairs of longs to display */
    swap    %d1
    move.l  %d1,%d5
    lsr.l   #7,%d5
    move.w  %d5,(%a1)
    lsl.l   #1,%d1
    move.w  %d1,(%a1)
    swap    %d5
    move.w  %d5,(%a1)
    swap    %d1
    move.w  %d1,(%a1)

    swap    %d2
    move.l  %d2,%d5
    lsr.l   #7,%d5
    move.w  %d5,(%a1)
    lsl.l   #1,%d2
    move.w  %d2,(%a1)
    swap    %d5
    move.w  %d5,(%a1)
    swap    %d2
    move.w  %d2,(%a1)

    swap    %d3
    move.l  %d3,%d5
    lsr.l   #7,%d5
    move.w  %d5,(%a1)
    lsl.l   #1,%d3
    move.w  %d3,(%a1)
    swap    %d5
    move.w  %d5,(%a1)
    swap    %d3
    move.w  %d3,(%a1)

    swap    %d4
    move.l  %d4,%d5
    lsr.l   #7,%d5
    move.w  %d5,(%a1)
    lsl.l   #1,%d4
    move.w  %d4,(%a1)
    swap    %d5
    move.w  %d5,(%a1)
    swap    %d4
    move.w  %d4,(%a1)

    cmp.l   %a0,%a2         /* run %a0 up to last line bound */
    bhi.w   .wd_line_loop

.wd_long2_start:
    subq.l  #2,%d0          /* account for handling 2 words per loop */
    cmp.l   %a0,%d0         /* any (trailing longwords? */
    bls.b   .wd_long2_end   /* no: skip trailing longword loop */

.wd_long2_loop:
    move.l  (%a0)+,%d2      /* read longword */
    swap    %d2
    move.l  %d2,%d5
    lsr.l   #7,%d5
    move.w  %d5,(%a1)
    lsl.l   #1,%d2
    move.w  %d2,(%a1)
    swap    %d5
    move.w  %d5,(%a1)
    swap    %d2
    move.w  %d2,(%a1)
    cmp.l   %a0,%d0         /* run %a0 up to last long bound */
    bhi.b   .wd_long2_loop

.wd_long2_end:
    blo.b   .wd_word2_end   /* no final word: skip */

    move.w  (%a0)+,%d2      /* transfer final word */
    move.l  %d2,%d1
    lsr.l   #7,%d1
    move.w  %d1,(%a1)
    lsl.l   #1,%d2
    move.w  %d2,(%a1)

.wd_word2_end:
    movem.l (%sp),%d2-%d5/%a2
    lea.l   (20,%sp),%sp    /* restore registers */
    rts

.wd_end:
    .size   lcd_write_data,.wd_end-lcd_write_data
/* end lcd_write_data */