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Merge pull request #728 from argilo/reverse-speedup
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Use bit shifts in generic and byte_shuffle reverse
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@jdemel
jdemel authored Dec 17, 2023
2 parents af3399f + f5679d3 commit b8e7801
Showing 1 changed file with 36 additions and 112 deletions.
148 changes: 36 additions & 112 deletions kernels/volk/volk_32u_reverse_32u.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,50 +28,6 @@
* \endcode
*/
#ifndef INCLUDED_VOLK_32u_REVERSE_32u_U_H
struct dword_split {
int b00 : 1;
int b01 : 1;
int b02 : 1;
int b03 : 1;
int b04 : 1;
int b05 : 1;
int b06 : 1;
int b07 : 1;
int b08 : 1;
int b09 : 1;
int b10 : 1;
int b11 : 1;
int b12 : 1;
int b13 : 1;
int b14 : 1;
int b15 : 1;
int b16 : 1;
int b17 : 1;
int b18 : 1;
int b19 : 1;
int b20 : 1;
int b21 : 1;
int b22 : 1;
int b23 : 1;
int b24 : 1;
int b25 : 1;
int b26 : 1;
int b27 : 1;
int b28 : 1;
int b29 : 1;
int b30 : 1;
int b31 : 1;
};
struct char_split {
uint8_t b00 : 1;
uint8_t b01 : 1;
uint8_t b02 : 1;
uint8_t b03 : 1;
uint8_t b04 : 1;
uint8_t b05 : 1;
uint8_t b06 : 1;
uint8_t b07 : 1;
};

// Idea from "Bit Twiddling Hacks", which dedicates this method to public domain
// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
Expand Down Expand Up @@ -100,42 +56,26 @@ static const unsigned char BitReverseTable256[] = {
static inline void
volk_32u_reverse_32u_generic(uint32_t* out, const uint32_t* in, unsigned int num_points)
{
const struct dword_split* in_ptr = (const struct dword_split*)in;
struct dword_split* out_ptr = (struct dword_split*)out;
const uint32_t* in_ptr = in;
uint32_t* out_ptr = out;
unsigned int number = 0;
for (; number < num_points; ++number) {
out_ptr->b00 = in_ptr->b31;
out_ptr->b01 = in_ptr->b30;
out_ptr->b02 = in_ptr->b29;
out_ptr->b03 = in_ptr->b28;
out_ptr->b04 = in_ptr->b27;
out_ptr->b05 = in_ptr->b26;
out_ptr->b06 = in_ptr->b25;
out_ptr->b07 = in_ptr->b24;
out_ptr->b08 = in_ptr->b23;
out_ptr->b09 = in_ptr->b22;
out_ptr->b10 = in_ptr->b21;
out_ptr->b11 = in_ptr->b20;
out_ptr->b12 = in_ptr->b19;
out_ptr->b13 = in_ptr->b18;
out_ptr->b14 = in_ptr->b17;
out_ptr->b15 = in_ptr->b16;
out_ptr->b16 = in_ptr->b15;
out_ptr->b17 = in_ptr->b14;
out_ptr->b18 = in_ptr->b13;
out_ptr->b19 = in_ptr->b12;
out_ptr->b20 = in_ptr->b11;
out_ptr->b21 = in_ptr->b10;
out_ptr->b22 = in_ptr->b09;
out_ptr->b23 = in_ptr->b08;
out_ptr->b24 = in_ptr->b07;
out_ptr->b25 = in_ptr->b06;
out_ptr->b26 = in_ptr->b05;
out_ptr->b27 = in_ptr->b04;
out_ptr->b28 = in_ptr->b03;
out_ptr->b29 = in_ptr->b02;
out_ptr->b30 = in_ptr->b01;
out_ptr->b31 = in_ptr->b00;
*out_ptr = (((*in_ptr >> 31) & 1) << 0) | (((*in_ptr >> 30) & 1) << 1) |
(((*in_ptr >> 29) & 1) << 2) | (((*in_ptr >> 28) & 1) << 3) |
(((*in_ptr >> 27) & 1) << 4) | (((*in_ptr >> 26) & 1) << 5) |
(((*in_ptr >> 25) & 1) << 6) | (((*in_ptr >> 24) & 1) << 7) |
(((*in_ptr >> 23) & 1) << 8) | (((*in_ptr >> 22) & 1) << 9) |
(((*in_ptr >> 21) & 1) << 10) | (((*in_ptr >> 20) & 1) << 11) |
(((*in_ptr >> 19) & 1) << 12) | (((*in_ptr >> 18) & 1) << 13) |
(((*in_ptr >> 17) & 1) << 14) | (((*in_ptr >> 16) & 1) << 15) |
(((*in_ptr >> 15) & 1) << 16) | (((*in_ptr >> 14) & 1) << 17) |
(((*in_ptr >> 13) & 1) << 18) | (((*in_ptr >> 12) & 1) << 19) |
(((*in_ptr >> 11) & 1) << 20) | (((*in_ptr >> 10) & 1) << 21) |
(((*in_ptr >> 9) & 1) << 22) | (((*in_ptr >> 8) & 1) << 23) |
(((*in_ptr >> 7) & 1) << 24) | (((*in_ptr >> 6) & 1) << 25) |
(((*in_ptr >> 5) & 1) << 26) | (((*in_ptr >> 4) & 1) << 27) |
(((*in_ptr >> 3) & 1) << 28) | (((*in_ptr >> 2) & 1) << 29) |
(((*in_ptr >> 1) & 1) << 30) | (((*in_ptr >> 0) & 1) << 31);
++in_ptr;
++out_ptr;
}
Expand All @@ -151,44 +91,28 @@ static inline void volk_32u_reverse_32u_byte_shuffle(uint32_t* out,
uint32_t* out_ptr = out;
unsigned int number = 0;
for (; number < num_points; ++number) {
const struct char_split* in8 = (const struct char_split*)in_ptr;
struct char_split* out8 = (struct char_split*)out_ptr;
const uint8_t* in8 = (const uint8_t*)in_ptr;
uint8_t* out8 = (uint8_t*)out_ptr;

out8[3].b00 = in8[0].b07;
out8[3].b01 = in8[0].b06;
out8[3].b02 = in8[0].b05;
out8[3].b03 = in8[0].b04;
out8[3].b04 = in8[0].b03;
out8[3].b05 = in8[0].b02;
out8[3].b06 = in8[0].b01;
out8[3].b07 = in8[0].b00;
out8[3] = (((in8[0] >> 7) & 1) << 0) | (((in8[0] >> 6) & 1) << 1) |
(((in8[0] >> 5) & 1) << 2) | (((in8[0] >> 4) & 1) << 3) |
(((in8[0] >> 3) & 1) << 4) | (((in8[0] >> 2) & 1) << 5) |
(((in8[0] >> 1) & 1) << 6) | (((in8[0] >> 0) & 1) << 7);

out8[2].b00 = in8[1].b07;
out8[2].b01 = in8[1].b06;
out8[2].b02 = in8[1].b05;
out8[2].b03 = in8[1].b04;
out8[2].b04 = in8[1].b03;
out8[2].b05 = in8[1].b02;
out8[2].b06 = in8[1].b01;
out8[2].b07 = in8[1].b00;
out8[2] = (((in8[1] >> 7) & 1) << 0) | (((in8[1] >> 6) & 1) << 1) |
(((in8[1] >> 5) & 1) << 2) | (((in8[1] >> 4) & 1) << 3) |
(((in8[1] >> 3) & 1) << 4) | (((in8[1] >> 2) & 1) << 5) |
(((in8[1] >> 1) & 1) << 6) | (((in8[1] >> 0) & 1) << 7);

out8[1].b00 = in8[2].b07;
out8[1].b01 = in8[2].b06;
out8[1].b02 = in8[2].b05;
out8[1].b03 = in8[2].b04;
out8[1].b04 = in8[2].b03;
out8[1].b05 = in8[2].b02;
out8[1].b06 = in8[2].b01;
out8[1].b07 = in8[2].b00;
out8[1] = (((in8[2] >> 7) & 1) << 0) | (((in8[2] >> 6) & 1) << 1) |
(((in8[2] >> 5) & 1) << 2) | (((in8[2] >> 4) & 1) << 3) |
(((in8[2] >> 3) & 1) << 4) | (((in8[2] >> 2) & 1) << 5) |
(((in8[2] >> 1) & 1) << 6) | (((in8[2] >> 0) & 1) << 7);

out8[0].b00 = in8[3].b07;
out8[0].b01 = in8[3].b06;
out8[0].b02 = in8[3].b05;
out8[0].b03 = in8[3].b04;
out8[0].b04 = in8[3].b03;
out8[0].b05 = in8[3].b02;
out8[0].b06 = in8[3].b01;
out8[0].b07 = in8[3].b00;
out8[0] = (((in8[3] >> 7) & 1) << 0) | (((in8[3] >> 6) & 1) << 1) |
(((in8[3] >> 5) & 1) << 2) | (((in8[3] >> 4) & 1) << 3) |
(((in8[3] >> 3) & 1) << 4) | (((in8[3] >> 2) & 1) << 5) |
(((in8[3] >> 1) & 1) << 6) | (((in8[3] >> 0) & 1) << 7);
++in_ptr;
++out_ptr;
}
Expand Down

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