[FB PATCH] cfbimgblt isn't 64-bit clean

From: Richard Henderson (rth@twiddle.net)
Date: Fri Dec 27 2002 - 18:18:43 EST


The text is written as if it's thinking about handling 64-bit
unsigned long, but it doesn't. The tables that map bits to
pixels are completely unprepared for this.

I thought about widening the tables, but I thought they'd get
unreasonably large. There's no reason not to go ahead and
handle this 32-bits at a time.

I've isolated this choice to two defines at the top of the
file, WORD and BITS_PER_WORD, so it'll not be _that_ hard to
change if someone disagrees.

r~

You can import this changeset into BK by piping this whole message to:
'| bk receive [path to repository]' or apply the patch as usual.

===================================================================

ChangeSet@1.958, 2002-12-27 15:12:24-08:00, rth@are.twiddle.net
  [FB] Use u32 instead of unsigned long for cfbimgblt bit ops.
  The code that maps bits to pixels is not prepared to handle
  a 64-bit long.

 cfbimgblt.c | 94 +++++++++++++++++++++++++++++++-----------------------------
 1 files changed, 49 insertions, 45 deletions

diff -Nru a/drivers/video/cfbimgblt.c b/drivers/video/cfbimgblt.c
--- a/drivers/video/cfbimgblt.c Fri Dec 27 15:16:03 2002
+++ b/drivers/video/cfbimgblt.c Fri Dec 27 15:16:03 2002
@@ -21,13 +21,13 @@
  *
  * FIXME
  * The code for 24 bit is horrible. It copies byte by byte size instead of
- * longs like the other sizes. Needs to be optimized.
+ * words like the other sizes. Needs to be optimized.
  *
  * Tony:
  * Incorporate mask tables similar to fbcon-cfb*.c in 2.4 API. This speeds
  * up the code significantly.
  *
- * Code for depths not multiples of BITS_PER_LONG is still kludgy, which is
+ * Code for depths not multiples of BITS_PER_WORD is still kludgy, which is
  * still processed a bit at a time.
  *
  * Also need to add code to deal with cards endians that are different than
@@ -48,7 +48,11 @@
 #define DPRINTK(fmt, args...)
 #endif
 
-static u32 cfb_tab8[] = {
+/* The following code can *not* handle a 64-bit long. */
+#define WORD u32
+#define BITS_PER_WORD 32
+
+static WORD const cfb_tab8[] = {
 #if defined(__BIG_ENDIAN)
     0x00000000,0x000000ff,0x0000ff00,0x0000ffff,
     0x00ff0000,0x00ff00ff,0x00ffff00,0x00ffffff,
@@ -64,7 +68,7 @@
 #endif
 };
 
-static u32 cfb_tab16[] = {
+static WORD const cfb_tab16[] = {
 #if defined(__BIG_ENDIAN)
     0x00000000, 0x0000ffff, 0xffff0000, 0xffffffff
 #elif defined(__LITTLE_ENDIAN)
@@ -74,11 +78,11 @@
 #endif
 };
 
-static u32 cfb_tab32[] = {
+static WORD const cfb_tab32[] = {
         0x00000000, 0xffffffff
 };
 
-#if BITS_PER_LONG == 32
+#if BITS_PER_WORD == 32
 #define FB_WRITEL fb_writel
 #define FB_READL fb_readl
 #else
@@ -87,7 +91,7 @@
 #endif
 
 #if defined (__BIG_ENDIAN)
-#define LEFT_POS(bpp) (BITS_PER_LONG - bpp)
+#define LEFT_POS(bpp) (BITS_PER_WORD - bpp)
 #define NEXT_POS(pos, bpp) ((pos) -= (bpp))
 #define SHIFT_HIGH(val, bits) ((val) >> (bits))
 #define SHIFT_LOW(val, bits) ((val) << (bits))
@@ -99,25 +103,25 @@
 #endif
 
 static inline void color_imageblit(struct fb_image *image, struct fb_info *p, u8 *dst1,
- unsigned long start_index, unsigned long pitch_index)
+ WORD start_index, WORD pitch_index)
 {
         /* Draw the penguin */
         int i, n;
- unsigned long bitmask = SHIFT_LOW(~0UL, BITS_PER_LONG - p->var.bits_per_pixel);
- unsigned long *palette = (unsigned long *) p->pseudo_palette;
- unsigned long *dst, *dst2, color = 0, val, shift;
- unsigned long null_bits = BITS_PER_LONG - p->var.bits_per_pixel;
+ WORD bitmask = SHIFT_LOW(~0UL, BITS_PER_WORD - p->var.bits_per_pixel);
+ u32 *palette = (u32 *) p->pseudo_palette;
+ WORD *dst, *dst2, color = 0, val, shift;
+ WORD null_bits = BITS_PER_WORD - p->var.bits_per_pixel;
         u8 *src = image->data;
 
- dst2 = (unsigned long *) dst1;
+ dst2 = (WORD *) dst1;
         for (i = image->height; i--; ) {
                 n = image->width;
- dst = (unsigned long *) dst1;
+ dst = (WORD *) dst1;
                 shift = 0;
                 val = 0;
                 
                 if (start_index) {
- unsigned long start_mask = ~(SHIFT_HIGH(~0UL, start_index));
+ WORD start_mask = ~(SHIFT_HIGH(~0UL, start_index));
 
                         val = FB_READL(dst) & start_mask;
                         shift = start_index;
@@ -134,14 +138,14 @@
                                 if (shift == null_bits)
                                         val = 0;
                                 else
- val = SHIFT_LOW(color, BITS_PER_LONG - shift);
+ val = SHIFT_LOW(color, BITS_PER_WORD - shift);
                         }
                         shift += p->var.bits_per_pixel;
- shift &= (BITS_PER_LONG - 1);
+ shift &= (BITS_PER_WORD - 1);
                         src++;
                 }
                 if (shift) {
- unsigned long end_mask = SHIFT_HIGH(~0UL, shift);
+ WORD end_mask = SHIFT_HIGH(~0UL, shift);
 
                         FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                 }
@@ -149,35 +153,35 @@
                 if (pitch_index) {
                         dst2 += p->fix.line_length;
                         dst1 = (char *) dst2;
- (unsigned long) dst1 &= ~(sizeof(unsigned long) - 1);
+ (size_t) dst1 &= ~(sizeof(WORD) - 1);
 
                         start_index += pitch_index;
- start_index &= BITS_PER_LONG - 1;
+ start_index &= BITS_PER_WORD - 1;
                 }
         }
 }
 
 static inline void slow_imageblit(struct fb_image *image, struct fb_info *p, u8 *dst1,
- unsigned long fgcolor, unsigned long bgcolor,
- unsigned long start_index, unsigned long pitch_index)
+ WORD fgcolor, WORD bgcolor,
+ WORD start_index, WORD pitch_index)
 {
- unsigned long i, j, l = 8;
- unsigned long shift, color, bpp = p->var.bits_per_pixel;
- unsigned long *dst, *dst2, val, pitch = p->fix.line_length;
- unsigned long null_bits = BITS_PER_LONG - bpp;
+ WORD i, j, l = 8;
+ WORD shift, color, bpp = p->var.bits_per_pixel;
+ WORD *dst, *dst2, val, pitch = p->fix.line_length;
+ WORD null_bits = BITS_PER_WORD - bpp;
         u8 *src = image->data;
         
- dst2 = (unsigned long *) dst1;
+ dst2 = (WORD *) dst1;
 
         for (i = image->height; i--; ) {
                 shift = 0;
                 val = 0;
                 j = image->width;
- dst = (unsigned long *) dst1;
+ dst = (WORD *) dst1;
 
                 /* write leading bits */
                 if (start_index) {
- unsigned long start_mask = ~(SHIFT_HIGH(~0UL, start_index));
+ WORD start_mask = ~(SHIFT_HIGH(~0UL, start_index));
 
                         val = FB_READL(dst) & start_mask;
                         shift = start_index;
@@ -196,15 +200,15 @@
                                 if (shift == null_bits)
                                         val = 0;
                                 else
- val = SHIFT_LOW(color, BITS_PER_LONG - shift);
+ val = SHIFT_LOW(color, BITS_PER_WORD - shift);
                         }
                         shift += bpp;
- shift &= (BITS_PER_LONG - 1);
+ shift &= (BITS_PER_WORD - 1);
                         if (!l) { l = 8; src++; };
                 }
                 /* write trailing bits */
                  if (shift) {
- unsigned long end_mask = SHIFT_HIGH(~0UL, shift);
+ WORD end_mask = SHIFT_HIGH(~0UL, shift);
 
                         FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
                 }
@@ -213,24 +217,24 @@
                 if (pitch_index) {
                         dst2 += pitch;
                         dst1 = (char *) dst2;
- (unsigned long) dst1 &= ~(sizeof(unsigned long) - 1);
+ (size_t) dst1 &= ~(sizeof(WORD) - 1);
 
                         start_index += pitch_index;
- start_index &= BITS_PER_LONG - 1;
+ start_index &= BITS_PER_WORD - 1;
                 }
                 
         }
 }
 
 static inline void fast_imageblit(struct fb_image *image, struct fb_info *p, u8 *dst1,
- unsigned long fgcolor, unsigned long bgcolor)
+ WORD fgcolor, WORD bgcolor)
 {
         int i, j, k, l = 8, n;
- unsigned long bit_mask, end_mask, eorx;
- unsigned long fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
- unsigned long tmp = (1 << bpp) - 1;
- unsigned long ppw = BITS_PER_LONG/bpp, ppos;
- unsigned long *dst;
+ WORD bit_mask, end_mask, eorx;
+ WORD fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
+ WORD tmp = (1 << bpp) - 1;
+ WORD ppw = BITS_PER_WORD/bpp, ppos;
+ WORD *dst;
         u32 *tab = NULL;
         char *src = image->data;
                 
@@ -263,7 +267,7 @@
         k = image->width/ppw;
 
         for (i = image->height; i--; ) {
- dst = (unsigned long *) dst1;
+ dst = (WORD *) dst1;
                 
                 for (j = k; j--; ) {
                         l -= ppw;
@@ -291,8 +295,8 @@
 void cfb_imageblit(struct fb_info *p, struct fb_image *image)
 {
         int x2, y2, vxres, vyres;
- unsigned long fgcolor, bgcolor, start_index, bitstart, pitch_index = 0;
- unsigned long bpl = sizeof(unsigned long), bpp = p->var.bits_per_pixel;
+ WORD fgcolor, bgcolor, start_index, bitstart, pitch_index = 0;
+ WORD bpl = sizeof(WORD), bpp = p->var.bits_per_pixel;
         u8 *dst1;
 
         vxres = p->var.xres_virtual;
@@ -315,7 +319,7 @@
         image->height = y2 - image->dy;
 
         bitstart = (image->dy * p->fix.line_length * 8) + (image->dx * bpp);
- start_index = bitstart & (BITS_PER_LONG - 1);
+ start_index = bitstart & (BITS_PER_WORD - 1);
         pitch_index = (p->fix.line_length & (bpl - 1)) * 8;
 
         bitstart /= 8;
@@ -332,7 +336,7 @@
                         bgcolor = image->bg_color;
                 }
                 
- if (BITS_PER_LONG % bpp == 0 && !start_index && !pitch_index &&
+ if (BITS_PER_WORD % bpp == 0 && !start_index && !pitch_index &&
                     bpp >= 8 && bpp <= 32 && (image->width & 7) == 0)
                         fast_imageblit(image, p, dst1, fgcolor, bgcolor);
                 else

===================================================================

This BitKeeper patch contains the following changesets:
+
## Wrapped with gzip_uu ##

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end
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This archive was generated by hypermail 2b29 : Tue Dec 31 2002 - 22:00:11 EST