ARM: pipelined NEON implementation of bilinear scaled 'src_8888_8888'

Performance of the inner loop when working with the data in L1 cache:
    ARM Cortex-A8: 41 cycles per 4 pixels (no stalls and partial dual issue)
    ARM Cortex-A9: 48 cycles per 4 pixels (no stalls)

It might be still possible to improve performance even more on ARM Cortex-A8
with a better use of dual issue.

Benchmark on ARM Cortex-A8 r1p3 @600MHz, 32-bit LPDDR @166MHz:
 Microbenchmark (scaling 2000x2000 image with scale factor close to 1x):
  before: op=1, src=20028888, dst=20028888, speed=40.38 MPix/s
  after:  op=1, src=20028888, dst=20028888, speed=48.47 MPix/s

Benchmark on ARM Cortex-A8 r2p2 @1GHz, 32-bit LPDDR @200MHz:
 Microbenchmark (scaling 2000x2000 image with scale factor close to 1x):
  before: op=1, src=20028888, dst=20028888, speed=79.68 MPix/s
  after:  op=1, src=20028888, dst=20028888, speed=93.11 MPix/s

1 files changed, 127 insertions, 0 deletions

diff --git a/pixman/pixman-arm-neon-asm.S b/pixman/pixman-arm-neon-asm.S
index 839ef9f..1877f79 100644
--- a/pixman/pixman-arm-neon-asm.S
+++ b/pixman/pixman-arm-neon-asm.S
@@ -2813,6 +2813,133 @@ pixman_asm_function fname
 
 .endm
 
+/*****************************************************************************/
+
+.set have_bilinear_interpolate_four_pixels_8888_8888, 1
+
+.macro bilinear_interpolate_four_pixels_8888_8888_head
+    mov       TMP1, X, asr #16
+    add       X, X, UX
+    add       TMP1, TOP, TMP1, asl #2
+    mov       TMP2, X, asr #16
+    add       X, X, UX
+    add       TMP2, TOP, TMP2, asl #2
+
+    vld1.32   {d22}, [TMP1], STRIDE
+    vld1.32   {d23}, [TMP1]
+    mov       TMP3, X, asr #16
+    add       X, X, UX
+    add       TMP3, TOP, TMP3, asl #2
+    vmull.u8  q8, d22, d28
+    vmlal.u8  q8, d23, d29
+
+    vld1.32   {d22}, [TMP2], STRIDE
+    vld1.32   {d23}, [TMP2]
+    mov       TMP4, X, asr #16
+    add       X, X, UX
+    add       TMP4, TOP, TMP4, asl #2
+    vmull.u8  q9, d22, d28
+    vmlal.u8  q9, d23, d29
+
+    vld1.32   {d22}, [TMP3], STRIDE
+    vld1.32   {d23}, [TMP3]
+    vmull.u8  q10, d22, d28
+    vmlal.u8  q10, d23, d29
+
+    vshll.u16 q0, d16, #8
+    vmlsl.u16 q0, d16, d30
+    vmlal.u16 q0, d17, d30
+
+    pld       [TMP4, PF_OFFS]
+    vld1.32   {d16}, [TMP4], STRIDE
+    vld1.32   {d17}, [TMP4]
+    pld       [TMP4, PF_OFFS]
+    vmull.u8  q11, d16, d28
+    vmlal.u8  q11, d17, d29
+
+    vshll.u16 q1, d18, #8
+    vmlsl.u16 q1, d18, d31
+.endm
+
+.macro bilinear_interpolate_four_pixels_8888_8888_tail
+    vmlal.u16 q1, d19, d31
+    vshr.u16  q15, q12, #8
+    vshll.u16 q2, d20, #8
+    vmlsl.u16 q2, d20, d30
+    vmlal.u16 q2, d21, d30
+    vshll.u16 q3, d22, #8
+    vmlsl.u16 q3, d22, d31
+    vmlal.u16 q3, d23, d31
+    vadd.u16  q12, q12, q13
+    vshrn.u32 d0, q0, #16
+    vshrn.u32 d1, q1, #16
+    vshrn.u32 d4, q2, #16
+    vshr.u16  q15, q12, #8
+    vshrn.u32 d5, q3, #16
+    vmovn.u16 d6, q0
+    vmovn.u16 d7, q2
+    vadd.u16  q12, q12, q13
+    vst1.32   {d6, d7}, [OUT, :128]!
+.endm
+
+.macro bilinear_interpolate_four_pixels_8888_8888_tail_head
+    mov       TMP1, X, asr #16
+    add       X, X, UX
+    add       TMP1, TOP, TMP1, asl #2
+    mov       TMP2, X, asr #16
+    add       X, X, UX
+    add       TMP2, TOP, TMP2, asl #2
+        vmlal.u16 q1, d19, d31
+        vshr.u16  q15, q12, #8
+        vshll.u16 q2, d20, #8
+        vmlsl.u16 q2, d20, d30
+        vmlal.u16 q2, d21, d30
+        vshll.u16 q3, d22, #8
+    vld1.32   {d20}, [TMP1], STRIDE
+        vmlsl.u16 q3, d22, d31
+        vmlal.u16 q3, d23, d31
+    vld1.32   {d21}, [TMP1]
+    vmull.u8  q8, d20, d28
+    vmlal.u8  q8, d21, d29
+        vshrn.u32 d0, q0, #16
+        vshrn.u32 d1, q1, #16
+        vshrn.u32 d4, q2, #16
+    vld1.32   {d22}, [TMP2], STRIDE
+        vshrn.u32 d5, q3, #16
+        vadd.u16  q12, q12, q13
+    vld1.32   {d23}, [TMP2]
+    vmull.u8  q9, d22, d28
+    mov       TMP3, X, asr #16
+    add       X, X, UX
+    add       TMP3, TOP, TMP3, asl #2
+    mov       TMP4, X, asr #16
+    add       X, X, UX
+    add       TMP4, TOP, TMP4, asl #2
+    vmlal.u8  q9, d23, d29
+    vld1.32   {d22}, [TMP3], STRIDE
+        vshr.u16  q15, q12, #8
+    vld1.32   {d23}, [TMP3]
+    vmull.u8  q10, d22, d28
+    vmlal.u8  q10, d23, d29
+        vmovn.u16 d6, q0
+    vshll.u16 q0, d16, #8
+        vmovn.u16 d7, q2
+    vmlsl.u16 q0, d16, d30
+    vmlal.u16 q0, d17, d30
+    pld       [TMP4, PF_OFFS]
+    vld1.32   {d16}, [TMP4], STRIDE
+        vadd.u16  q12, q12, q13
+    vld1.32   {d17}, [TMP4]
+    pld       [TMP4, PF_OFFS]
+    vmull.u8  q11, d16, d28
+    vmlal.u8  q11, d17, d29
+        vst1.32   {d6, d7}, [OUT, :128]!
+    vshll.u16 q1, d18, #8
+    vmlsl.u16 q1, d18, d31
+.endm
+
+/*****************************************************************************/
+
 generate_bilinear_scanline_func \
     pixman_scaled_bilinear_scanline_8888_8888_SRC_asm_neon, 8888, 8888, \
     2, 2, 28, BILINEAR_FLAG_UNROLL_4