Greyscale library: Changed the internal data format once more (separated pixel values and phases), allowing for further optimisation of drawing, scrolling etc. * Optimised grey phase blitting in the core reduces CPU load on all architectures, most significantly on coldfire. Previous version was too slow to keep up at 45MHz, leading to unwanted graininess (update frequency was halved). Also fixed screendump on 2bpp targets with vertical pixel packing.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16043 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 147 insertions, 54 deletions

diff --git a/firmware/target/coldfire/iaudio/m5/lcd-as-m5.S b/firmware/target/coldfire/iaudio/m5/lcd-as-m5.S
index 7e89815ec8..0ec98e4589 100644
--- a/firmware/target/coldfire/iaudio/m5/lcd-as-m5.S
+++ b/firmware/target/coldfire/iaudio/m5/lcd-as-m5.S
@@ -88,57 +88,146 @@ lcd_write_data:
     .type       lcd_grey_data,@function
 
 lcd_grey_data:
-    lea.l   (-4*4, %sp), %sp
-    movem.l %d2-%d5, (%sp)
-    movem.l (4*4+4, %sp), %a0-%a1 /* Data pointer */
-    move.l  %a1, %d0            /* Length */
-    lea     0xf0008002, %a1     /* LCD data port */
-    move.l  #0xff00ff00, %d2    /* mask for splitting value/phase pairs */
-
-.greyloop:
-    movem.l (%a0), %d4-%d5      /* fetch 4 pixel phase/value pairs at once */
-                                /* %d4 = p0v0p1v1, %d5 = p2v2p3v3 */
-    move.l  %d2, %d3            /* copy mask */
-    and.l   %d4, %d3            /* %d3 = p0--p1-- */
-    eor.l   %d3, %d4            /* %d4 = --v0--v1 */
-    lsr.l   #8, %d3             /* %d3 = --p0--p1 */
-
-    bclr.l  #23, %d3            /* Z = !(p0 & 0x80); p0 &= ~0x80; */
-    seq.b   %d1                 /* %d1 = ........................00000000 */
-    lsl.l   #2, %d1             /* %d1 = ......................00000000.. */
-    bclr.l  #7, %d3             /* Z = !(p1 & 0x80); p1 &= ~0x80; */
-    seq.b   %d1                 /* %d1 = ......................0011111111 */
-    lsl.l   #2, %d1             /* %d1 = ....................0011111111.. */
+    lea.l   (-9*4, %sp), %sp
+    movem.l %d2-%d5/%a2-%a6, (%sp)  /* free some registers */
+    movem.l (9*4+4, %sp), %a0-%a2   /* values, phases, length */
+    lea.l   (%a1, %a2.l*4), %a2     /* end address */
+    lea     0xf0008002, %a3     /* LCD data port */
+
+    moveq.l #15, %d3
+    add.l   %a1, %d3
+    and.l   #0xfffffff0, %d3    /* first line bound */
+    move.l  %a2, %d1
+    and.l   #0xfffffff0, %d1    /* last line bound */
+    cmp.l   %d3, %d1
+    bls.w   .g_tloop            /* no lines to copy - jump to tail loop */
+    cmp.l   %a1, %d0
+    bls.s   .g_lloop            /* no head blocks - jump to line loop */
+
+.g_hloop:
+    move.l  (%a1), %d2          /* fetch 4 pixel phases */
+
+    bclr.l  #31, %d2            /* Z = !(p0 & 0x80); p0 &= ~0x80; */
+    seq.b   %d0                 /* %d0 = ........................00000000 */
+    lsl.l   #2, %d0             /* %d0 = ......................00000000.. */
+    bclr.l  #23, %d2            /* Z = !(p1 & 0x80); p1 &= ~0x80; */
+    seq.b   %d0                 /* %d0 = ......................0011111111 */
+    lsl.l   #2, %d0             /* %d0 = ....................0011111111.. */
+    bclr.l  #15, %d2            /* Z = !(p2 & 0x80); p2 &= ~0x80; */
+    seq.b   %d0                 /* %d0 = ....................001122222222 */
+    lsl.l   #2, %d0             /* %d0 = ..................001122222222.. */
+    bclr.l  #7, %d2             /* Z = !(p3 & 0x80); p3 &= ~0x80; */
+    seq.b   %d0                 /* %d0 = ..................00112233333333 */
+    lsr.l   #6, %d0             /* %d0 = ........................00112233 */
+    move.w  %d0, (%a3)          /* write pixel block */
+    
+    add.l   (%a0)+, %d2         /* add 4 pixel values to the phases */
+    move.l  %d2, (%a1)+         /* store new phases, advance pointer */
+
+    cmp.l   %a1, %d3            /* go up to first line bound */
+    bhi.s   .g_hloop
+    
+.g_lloop:
+    movem.l (%a1), %d2-%d5
+    
+    bclr.l  #31, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #23, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #15, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #7, %d2
+    seq.b   %d0
+    lsr.l   #6, %d0
+    move.w  %d0, (%a3)
+
+    bclr.l  #31, %d3
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #23, %d3
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #15, %d3
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #7, %d3
+    seq.b   %d0
+    lsr.l   #6, %d0
+    move.w  %d0, (%a3)
     
-    add.l   %d4, %d3            /* p0 += v0; p1 += v1; */
-    move.b  %d3, (2, %a0)       /* store p1 */
-    swap    %d3
-    move.b  %d3, (%a0)          /* store p0 */
-
-    move.l  %d2, %d3            /* copy mask */
-    and.l   %d5, %d3            /* %d3 = p2--p3-- */
-    eor.l   %d3, %d5            /* %d5 = --v2--v3 */
-    lsr.l   #8, %d3             /* %d3 = --p2--p3 */
-
-    bclr.l  #23, %d3            /* Z = !(p2 & 0x80); p2 &= ~0x80; */
-    seq.b   %d1                 /* %d1 = ....................001122222222 */
-    lsl.l   #2, %d1             /* %d1 = ..................001122222222.. */
-    bclr.l  #7, %d3             /* Z = !(p3 & 0x80); p3 &= ~0x80; */
-    seq.b   %d1                 /* %d1 = ..................00112233333333 */
-    lsr.l   #6, %d1             /* %d1 = ........................00112233 */
-
-    add.l   %d5, %d3            /* p2 += v2; p3 += v3; */
-    move.b  %d3, (6, %a0)       /* store p3 */
-    swap    %d3
-    move.b  %d3, (4, %a0)       /* store p2 */
-
-    move.w  %d1, (%a1)          /* write pixel block */
-    addq.l  #8, %a0             /* advance address pointer */
-    subq.l  #1, %d0             /* any blocks left? */
-    bne.b   .greyloop
-
-    movem.l (%sp), %d2-%d5
-    lea.l   (4*4, %sp), %sp
+    bclr.l  #31, %d4
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #23, %d4
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #15, %d4
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #7, %d4
+    seq.b   %d0
+    lsr.l   #6, %d0
+    move.w  %d0, (%a3)
+    
+    bclr.l  #31, %d5
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #23, %d5
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #15, %d5
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #7, %d5
+    seq.b   %d0
+    lsr.l   #6, %d0
+    move.w  %d0, (%a3)
+    
+    movem.l (%a0), %d0/%a4-%a6
+    lea.l   (16, %a0), %a0
+    add.l   %d0, %d2
+    add.l   %a4, %d3
+    add.l   %a5, %d4
+    add.l   %a6, %d5
+    movem.l %d2-%d5, (%a1)
+    lea.l   (16, %a1), %a1
+
+    cmp.l   %a1, %d1            /* go up to last line bound */
+    bhi.w   .g_lloop
+    
+    cmp.l   %a1, %a2
+    bls.s   .g_no_tail
+
+.g_tloop:
+    move.l  (%a1), %d2
+
+    bclr.l  #31, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #23, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #15, %d2
+    seq.b   %d0
+    lsl.l   #2, %d0
+    bclr.l  #7, %d2
+    seq.b   %d0
+    lsr.l   #6, %d0
+    move.w  %d0, (%a3)
+
+    add.l   (%a0)+, %d2         /* go up to end address */
+    move.l  %d2, (%a1)+
+
+    cmp.l   %a1, %a2
+    bhi.s   .g_tloop
+
+.g_no_tail:
+    movem.l (%sp), %d2-%d5/%a2-%a6  /* restore registers */
+    lea.l   (9*4, %sp), %sp
     rts
+
 .gd_end:
     .size   lcd_grey_data,.gd_end-lcd_grey_data
diff --git a/firmware/target/coldfire/iaudio/m5/lcd-m5.c b/firmware/target/coldfire/iaudio/m5/lcd-m5.c
index 4f963795c7..be9d5a39b8 100644
--- a/firmware/target/coldfire/iaudio/m5/lcd-m5.c
+++ b/firmware/target/coldfire/iaudio/m5/lcd-m5.c
@@ -171,10 +171,13 @@ void lcd_blit(const unsigned char* data, int x, int by, int width,
     }
 }
 
+/* Helper function for lcd_grey_phase_blit(). */
+void lcd_grey_data(unsigned char *values, unsigned char *phases, int count);
+
 /* Performance function that works with an external buffer
    note that by and bheight are in 4-pixel units! */
-void lcd_grey_phase_blit(const struct grey_data *data, int x, int by, 
-                         int width, int bheight, int stride)
+void lcd_grey_phase_blit(unsigned char *values, unsigned char *phases,
+                         int x, int by, int width, int bheight, int stride)
 {
     stride <<= 2; /* 4 pixels per block */
     while (bheight--)
@@ -182,8 +185,9 @@ void lcd_grey_phase_blit(const struct grey_data *data, int x, int by,
         lcd_write_command_ex(LCD_CNTL_PAGE, by++, -1);
         lcd_write_command_ex(LCD_CNTL_COLUMN, x, -1);
         lcd_write_command(LCD_CNTL_DATA_WRITE);
-        lcd_grey_data(data, width);
-        data += stride;
+        lcd_grey_data(values, phases, width);
+        values += stride;
+        phases += stride;
     }
 }