gallium: Fix llvmpipe on big-endian machines

Squashed commit of the following:

commit 0857a7e105bfcbc4d1431b2cc56612094c747ca3
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:07 2013 -0400

    gallivm: Fix lp_build_rgba8_to_fi32_soa for big endian

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 0d65131649a8aa140e2db228ba779d685c4333e3
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:07 2013 -0400

    gallivm: Fix big-endian machines

    This adds a bit-shift count to the format table, and adds the concept of
    vector or bitwise alignment on gathers.

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 9740bda9b7dc894b629ed38be9b51059ce90818f
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:07 2013 -0400

    llvmpipe: Fix convert_to_blend_type on big-endian

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit ae037c2de0f029e4e99371c0de25560484f0d8df
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    util: Convert color pack to packed formats

    This fixes them on big-endian.

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 5b05ac0c89ae092ea8ba5bba9f739708d7396b5c
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    graw-xlib: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 51396e7d098cb6ff794391cf11afe4dbf86dbea0
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    format: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 417b60bc66eb450e68a92ab0e47f76e292b385e6
Author: Adam Jackson <ajax@redhat.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    st/dri: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 0934b2e022a5e0847d312c40734e2b44cac52fd8
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    st/xlib: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit a307ea3c3716a706963acce7966b5e405ba11db9
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    gbm: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 53eebdd253e1960a645ea278f31d7ef6a6cf4aeb
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    tests: Convert to packed formats

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 2f77fe3ee524945eacd546efcac34f7799fb3124
Author: Adam Jackson <ajax@redhat.com>
Date:   Tue Jun 18 13:07:37 2013 -0400

    gallium: Document packed formats

    Signed-off-by: Adam Jackson <ajax@redhat.com>

commit 1f1017159ce951f922210a430de9229f91f62714
Author: Richard Sandiford <r.sandiford@uk.ibm.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    gallium: Introduce 32-bit packed format names

    These are for interacting with buffers natively described in terms of
    bit shifts, like X11 visuals:

        uint32_t xyzw8888 = (x << 0) | (y << 8) | (z << 16) | (w << 24);

    Define these in terms of (endian-dependent) aliases to the array-style
    format names.

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Richard Sandiford <r.sandiford@uk.ibm.com>

commit 6cc7ab1ee66ed668da78c1d951dfd7782b4e786a
Author: Adam Jackson <ajax@redhat.com>
Date:   Mon Jun 3 12:10:32 2013 -0400

    gallium: Document format name conventions

    v2:
    - Fix a channel name thinko (Michel Dänzer)
    - Elaborate on SCALED versus INT
    - Add links to DirectX and FOURCC docs

    Signed-off-by: Adam Jackson <ajax@redhat.com>

commit df4d269e7fb62051a3c029b84147465001e5776e
Author: Adam Jackson <ajax@redhat.com>
Date:   Tue Jun 18 12:25:06 2013 -0400

    gallivm: Remove all notion of byte-swapping

    Signed-off-by: Adam Jackson <ajax@redhat.com>

Signed-off-by: Adam Jackson <ajax@redhat.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/src/gallium/docs/source/format.rst b/src/gallium/docs/source/format.rst
new file mode 100644
index 0000000000..f6d77d6236
--- /dev/null
+++ b/src/gallium/docs/source/format.rst
@@ -0,0 +1,61 @@
+Formats in gallium
+==================
+
+Gallium format names mostly follow D3D10 conventions, with some extensions.
+
+Format names like XnYnZnWn have the X component in the lowest-address n bits
+and the W component in the highest-address n bits; for B8G8R8A8, byte 0 is
+blue and byte 3 is alpha.  Note that platform endianness is not considered
+in this definition.  In C:
+
+    struct x8y8z8w8 { uint8_t x, y, z, w; };
+
+Format aliases like XYZWstrq are (s+t+r+q)-bit integers in host endianness,
+with the X component in the s least-significant bits of the integer.  In C:
+
+    uint32_t xyzw8888 = (x << 0) | (y << 8) | (z << 16) | (w << 24);
+
+Format suffixes affect the interpretation of the channel:
+
+- ``SINT``:     N bit signed integer [-2^(N-1) ... 2^(N-1) - 1]
+- ``SNORM``:    N bit signed integer normalized to [-1 ... 1]
+- ``SSCALED``:  N bit signed integer [-2^(N-1) ... 2^(N-1) - 1]
+- ``FIXED``:    Signed fixed point integer, (N/2 - 1) bits of mantissa
+- ``FLOAT``:    N bit IEEE754 float
+- ``NORM``:     Normalized integers, signed or unsigned per channel
+- ``UINT``:     N bit unsigned integer [0 ... 2^N - 1]
+- ``UNORM``:    N bit unsigned integer normalized to [0 ... 1]
+- ``USCALED``:  N bit unsigned integer [0 ... 2^N - 1]
+
+The difference between ``SINT`` and ``SSCALED`` is that the former are pure
+integers in shaders, while the latter are floats; likewise for ``UINT`` versus
+``USCALED``.
+
+There are two exceptions for ``FLOAT``.  ``R9G9B9E5_FLOAT`` is nine bits
+each of red green and blue mantissa, with a shared five bit exponent.
+``R11G11B10_FLOAT`` is five bits of exponent and five or six bits of mantissa
+for each color channel.
+
+For the ``NORM`` suffix, the signedness of each channel is indicated with an
+S or U after the number of channel bits, as in ``R5SG5SB6U_NORM``.
+
+The ``SRGB`` suffix is like ``UNORM`` in range, but in the sRGB colorspace.
+
+Compressed formats are named first by the compression format string (``DXT1``,
+``ETC1``, etc), followed by a format-specific subtype.  Refer to the
+appropriate compression spec for details.
+
+Formats used in video playback are named by their FOURCC code.
+
+Format names with an embedded underscore are subsampled.  ``R8G8_B8G8`` is a
+single 32-bit block of two pixels, where the R and B values are repeated in
+both pixels.
+
+References
+----------
+
+DirectX Graphics Infrastructure documentation on DXGI_FORMAT enum:
+http://msdn.microsoft.com/en-us/library/windows/desktop/bb173059%28v=vs.85%29.aspx
+
+FOURCC codes for YUV formats:
+http://www.fourcc.org/yuv.php