[Pixman] [PATCH 36/37] armv6: Add fetcher for a8 bilinear-interpolation scaled images

[Ben Avison]

This is constrained to support X increments in the positive X direction only.
It also doesn't attempt to support any form of image repeat.

Here are some affine-bench results for a variety of horizontal and vertical
scaling factors.

Before:
    x increment   0.5   0.75  1.0   1.5   2.0
y increment
    0.5            6.2   6.2   6.2   6.1   6.0
    0.75           6.2   6.1   6.1   6.0   5.9
    1.0            6.2   6.1         5.9   5.8
    1.5            6.1   6.0   5.9   5.8   5.6
    2.0            6.1   6.0   5.9   5.7   5.5

After:
    x increment   0.5   0.75  1.0   1.5   2.0
y increment
    0.5           22.2  21.2  19.7  21.0  20.4
    0.75          19.4  18.3  16.7  18.2  17.4
    1.0           24.7  22.3        22.1  20.4
    1.5           14.2  13.0  11.5  12.9  12.1
    2.0           12.0  10.9   9.5  10.8  10.0

Improvement:
    x increment   0.5     0.75    1.0     1.5     2.0
y increment
    0.5           +256.4% +242.8% +219.6% +246.6% +241.3%
    0.75          +212.9% +197.8% +173.7% +203.4% +195.1%
    1.0           +300.2% +265.9%         +273.4% +251.2%
    1.5           +131.8% +115.6%  +93.1% +123.2% +114.0%
    2.0            +97.7%  +82.9%  +62.8%  +91.0%  +82.9%
---
 pixman/pixman-arm-simd-asm-scaled.S |   15 +++++++++++++++
 pixman/pixman-arm-simd.c            |   26 ++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/pixman/pixman-arm-simd-asm-scaled.S b/pixman/pixman-arm-simd-asm-scaled.S
index 017b6b2..bae1665 100644
--- a/pixman/pixman-arm-simd-asm-scaled.S
+++ b/pixman/pixman-arm-simd-asm-scaled.S
@@ -233,6 +233,21 @@ generate_bilinear_scaled_cover_functions  32, x8r8g8b8, 3, 3, 3, 3, 3, 3, 3, 3,
 
 generate_bilinear_scaled_cover_functions  16, r5g6b5, 2, 2, 3, 3, 3, 3, 3, 3, nop_macro, convert_0565_08080808
 
+.macro init_8_08080808
+        @ Ideally we'd also skip all subsequent processing of the red/blue
+        @ components since they remain 0 throughout. Also, there may be
+        @ some scope for simplifying the alpha component processing.
+        @ However, this approach is still an improvement for now.
+        mov     RB_IN0, #0
+        mov     RB_IN1, #0
+.endm
+
+.macro convert_8_08080808  in_ag, rb
+        mov     \in_ag, \in_ag, lsl #16
+.endm
+
+generate_bilinear_scaled_cover_functions  8, a8, 2, 2, 3, 3, 3, 3, 3, 3, init_8_08080808, convert_8_08080808
+
 /******************************************************************************/
 
 .macro pass2_1pixel_internal  t0, t1, b0, b1, tmp, mul, d
diff --git a/pixman/pixman-arm-simd.c b/pixman/pixman-arm-simd.c
index 5cfbb8c..e27b831 100644
--- a/pixman/pixman-arm-simd.c
+++ b/pixman/pixman-arm-simd.c
@@ -460,6 +460,24 @@ static inline void armv6_convert_adjacent_r5g6b5 (const void *void_source,
 
 BIND_GET_SCANLINE_BILINEAR_SCALED_COVER(armv6, r5g6b5, uint16_t)
 
+static inline void armv6_convert_adjacent_a8 (const void *void_source,
+                                              int         x,
+                                              uint32_t   *lag,
+                                              uint32_t   *rag,
+                                              uint32_t   *lrb,
+                                              uint32_t   *rrb)
+{
+    const uint8_t *source = void_source;
+    uint32_t left  = source[x];
+    uint32_t right = source[x+1];
+    *lag = left << 16;
+    *rag = right << 16;
+    *lrb = 0;
+    *rrb = 0;
+}
+
+BIND_GET_SCANLINE_BILINEAR_SCALED_COVER(armv6, a8, uint8_t)
+
 #define NEAREST_SCALED_COVER_USES_SRC_BUFFER(op, src_format, dst_format) \
     (PIXMAN_OP_##op != PIXMAN_OP_SRC ||                                  \
      (PIXMAN_##dst_format != PIXMAN_a8r8g8b8 &&                          \
@@ -901,6 +919,14 @@ static const pixman_iter_info_t arm_simd_iters[] =
       NULL
     },
 
+    { PIXMAN_a8,
+      PIXMAN_ARM_BILINEAR_SCALED_COVER_FLAGS,
+      ITER_NARROW | ITER_SRC,
+      armv6_get_scanline_bilinear_init_a8,
+      armv6_get_scanline_bilinear_scaled_cover_a8,
+      NULL
+    },
+
     { PIXMAN_null },
 };
 
-- 
1.7.5.4