[Qemu-devel] [PATCH v2] hw/display/pxa2xx_lcd: Fix 16bpp+alpha and 18bpp+alpha palette formats

[Qemu-devel] [PATCH v2] hw/display/pxa2xx_lcd: Fix 16bpp+alpha and 18bpp+alpha palette formats

[Peter Maydell]

The pxa2xx palette entry "16bpp plus transparency" format is
xxxxxxxTRRRRR000GGGGGG00BBBBB000, and "18bpp plus transparency" is
xxxxxxxTRRRRRR00GGGGGG00BBBBBB00.

Correct errors in the code for reading these and converting
them to the internal format. In particular, the buggy code
was attempting to mask out bit 24 of a uint16_t, which
Coverity spotted as an error.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
This is the remaining uncommitted patch from the set of 8 random
coverity fixes I sent a little while back.
Changes v1->v2:
 * use correct mask/shift for R component in 16bpp+transparency
 * we need to add 4 to the src ptr, not 2, for the 16bpp+transparency
   format, since each palette entry is 32 bits

 hw/display/pxa2xx_lcd.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/hw/display/pxa2xx_lcd.c b/hw/display/pxa2xx_lcd.c
index 80edb70..611fb17 100644
--- a/hw/display/pxa2xx_lcd.c
+++ b/hw/display/pxa2xx_lcd.c
@@ -620,24 +620,24 @@ static void pxa2xx_palette_parse(PXA2xxLCDState *s, int ch, int bpp)
             src += 2;
             break;
         case 1: /* 16 bpp plus transparency */
-            alpha = *(uint16_t *) src & (1 << 24);
+            alpha = *(uint32_t *) src & (1 << 24);
             if (s->control[0] & LCCR0_CMS)
-                r = g = b = *(uint16_t *) src & 0xff;
+                r = g = b = *(uint32_t *) src & 0xff;
             else {
-                r = (*(uint16_t *) src & 0xf800) >> 8;
-                g = (*(uint16_t *) src & 0x07e0) >> 3;
-                b = (*(uint16_t *) src & 0x001f) << 3;
+                r = (*(uint32_t *) src & 0xf80000) >> 16;
+                g = (*(uint32_t *) src & 0x00fc00) >> 8;
+                b = (*(uint32_t *) src & 0x0000f8);
             }
-            src += 2;
+            src += 4;
             break;
         case 2: /* 18 bpp plus transparency */
             alpha = *(uint32_t *) src & (1 << 24);
             if (s->control[0] & LCCR0_CMS)
                 r = g = b = *(uint32_t *) src & 0xff;
             else {
-                r = (*(uint32_t *) src & 0xf80000) >> 16;
+                r = (*(uint32_t *) src & 0xfc0000) >> 16;
                 g = (*(uint32_t *) src & 0x00fc00) >> 8;
-                b = (*(uint32_t *) src & 0x0000f8);
+                b = (*(uint32_t *) src & 0x0000fc);
             }
             src += 4;
             break;
-- 
1.9.2

Re: [Qemu-devel] [PATCH v2] hw/display/pxa2xx_lcd: Fix 16bpp+alpha and 18bpp+alpha palette formats

[Peter Crosthwaite]

On Fri, May 16, 2014 at 7:51 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
> The pxa2xx palette entry "16bpp plus transparency" format is
> xxxxxxxTRRRRR000GGGGGG00BBBBB000, and "18bpp plus transparency" is
> xxxxxxxTRRRRRR00GGGGGG00BBBBBB00.
>
> Correct errors in the code for reading these and converting
> them to the internal format. In particular, the buggy code
> was attempting to mask out bit 24 of a uint16_t, which
> Coverity spotted as an error.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

> ---
> This is the remaining uncommitted patch from the set of 8 random
> coverity fixes I sent a little while back.
> Changes v1->v2:
>  * use correct mask/shift for R component in 16bpp+transparency
>  * we need to add 4 to the src ptr, not 2, for the 16bpp+transparency
>    format, since each palette entry is 32 bits
>
>  hw/display/pxa2xx_lcd.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/hw/display/pxa2xx_lcd.c b/hw/display/pxa2xx_lcd.c
> index 80edb70..611fb17 100644
> --- a/hw/display/pxa2xx_lcd.c
> +++ b/hw/display/pxa2xx_lcd.c
> @@ -620,24 +620,24 @@ static void pxa2xx_palette_parse(PXA2xxLCDState *s, int ch, int bpp)
>              src += 2;
>              break;
>          case 1: /* 16 bpp plus transparency */
> -            alpha = *(uint16_t *) src & (1 << 24);
> +            alpha = *(uint32_t *) src & (1 << 24);
>              if (s->control[0] & LCCR0_CMS)
> -                r = g = b = *(uint16_t *) src & 0xff;
> +                r = g = b = *(uint32_t *) src & 0xff;
>              else {
> -                r = (*(uint16_t *) src & 0xf800) >> 8;
> -                g = (*(uint16_t *) src & 0x07e0) >> 3;
> -                b = (*(uint16_t *) src & 0x001f) << 3;
> +                r = (*(uint32_t *) src & 0xf80000) >> 16;
> +                g = (*(uint32_t *) src & 0x00fc00) >> 8;
> +                b = (*(uint32_t *) src & 0x0000f8);
>              }
> -            src += 2;
> +            src += 4;
>              break;
>          case 2: /* 18 bpp plus transparency */
>              alpha = *(uint32_t *) src & (1 << 24);
>              if (s->control[0] & LCCR0_CMS)
>                  r = g = b = *(uint32_t *) src & 0xff;
>              else {
> -                r = (*(uint32_t *) src & 0xf80000) >> 16;
> +                r = (*(uint32_t *) src & 0xfc0000) >> 16;
>                  g = (*(uint32_t *) src & 0x00fc00) >> 8;
> -                b = (*(uint32_t *) src & 0x0000f8);
> +                b = (*(uint32_t *) src & 0x0000fc);
>              }
>              src += 4;
>              break;
> --
> 1.9.2
>
>