2 /* palette_neon_intrinsics.c - NEON optimised palette expansion functions
4 * Copyright (c) 2018-2019 Cosmin Truta
5 * Copyright (c) 2017-2018 Arm Holdings. All rights reserved.
6 * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017.
8 * This code is released under the libpng license.
9 * For conditions of distribution and use, see the disclaimer
10 * and license in png.h
13 #include "../pngpriv.h"
15 #if PNG_ARM_NEON_IMPLEMENTATION == 1
17 #if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
18 # include <arm64_neon.h>
20 # include <arm_neon.h>
23 /* Build an RGBA8 palette from the separate RGB and alpha palettes. */
25 png_riffle_palette_neon(png_structrp png_ptr
)
27 png_const_colorp palette
= png_ptr
->palette
;
28 png_bytep riffled_palette
= png_ptr
->riffled_palette
;
29 png_const_bytep trans_alpha
= png_ptr
->trans_alpha
;
30 int num_trans
= png_ptr
->num_trans
;
33 /* Initially black, opaque. */
41 png_debug(1, "in png_riffle_palette_neon");
43 /* First, riffle the RGB colours into an RGBA8 palette.
44 * The alpha component is set to opaque for now.
46 for (i
= 0; i
< 256; i
+= 16)
48 uint8x16x3_t v
= vld3q_u8((png_const_bytep
)(palette
+ i
));
52 vst4q_u8(riffled_palette
+ (i
<< 2), w
);
55 /* Fix up the missing transparency values. */
56 for (i
= 0; i
< num_trans
; i
++)
57 riffled_palette
[(i
<< 2) + 3] = trans_alpha
[i
];
60 /* Expands a palettized row into RGBA8. */
62 png_do_expand_palette_rgba8_neon(png_structrp png_ptr
, png_row_infop row_info
,
63 png_const_bytep row
, png_bytepp ssp
, png_bytepp ddp
)
65 png_uint_32 row_width
= row_info
->width
;
66 const png_uint_32
*riffled_palette
=
67 (const png_uint_32
*)png_ptr
->riffled_palette
;
68 const png_uint_32 pixels_per_chunk
= 4;
71 png_debug(1, "in png_do_expand_palette_rgba8_neon");
74 if (row_width
< pixels_per_chunk
)
77 /* This function originally gets the last byte of the output row.
78 * The NEON part writes forward from a given position, so we have
79 * to seek this back by 4 pixels x 4 bytes.
81 *ddp
= *ddp
- ((pixels_per_chunk
* sizeof(png_uint_32
)) - 1);
83 for (i
= 0; i
< row_width
; i
+= pixels_per_chunk
)
86 png_bytep sp
= *ssp
- i
, dp
= *ddp
- (i
<< 2);
87 cur
= vld1q_dup_u32 (riffled_palette
+ *(sp
- 3));
88 cur
= vld1q_lane_u32(riffled_palette
+ *(sp
- 2), cur
, 1);
89 cur
= vld1q_lane_u32(riffled_palette
+ *(sp
- 1), cur
, 2);
90 cur
= vld1q_lane_u32(riffled_palette
+ *(sp
- 0), cur
, 3);
91 vst1q_u32((void *)dp
, cur
);
95 /* Remove the amount that wasn't processed. */
96 i
-= pixels_per_chunk
;
99 /* Decrement output pointers. */
101 *ddp
= *ddp
- (i
<< 2);
105 /* Expands a palettized row into RGB8. */
107 png_do_expand_palette_rgb8_neon(png_structrp png_ptr
, png_row_infop row_info
,
108 png_const_bytep row
, png_bytepp ssp
, png_bytepp ddp
)
110 png_uint_32 row_width
= row_info
->width
;
111 png_const_bytep palette
= (png_const_bytep
)png_ptr
->palette
;
112 const png_uint_32 pixels_per_chunk
= 8;
115 png_debug(1, "in png_do_expand_palette_rgb8_neon");
118 if (row_width
<= pixels_per_chunk
)
121 /* Seeking this back by 8 pixels x 3 bytes. */
122 *ddp
= *ddp
- ((pixels_per_chunk
* sizeof(png_color
)) - 1);
124 for (i
= 0; i
< row_width
; i
+= pixels_per_chunk
)
127 png_bytep sp
= *ssp
- i
, dp
= *ddp
- ((i
<< 1) + i
);
128 cur
= vld3_dup_u8(palette
+ sizeof(png_color
) * (*(sp
- 7)));
129 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 6)), cur
, 1);
130 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 5)), cur
, 2);
131 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 4)), cur
, 3);
132 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 3)), cur
, 4);
133 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 2)), cur
, 5);
134 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 1)), cur
, 6);
135 cur
= vld3_lane_u8(palette
+ sizeof(png_color
) * (*(sp
- 0)), cur
, 7);
136 vst3_u8((void *)dp
, cur
);
141 /* Remove the amount that wasn't processed. */
142 i
-= pixels_per_chunk
;
145 /* Decrement output pointers. */
147 *ddp
= *ddp
- ((i
<< 1) + i
);
151 #endif /* PNG_ARM_NEON_IMPLEMENTATION */