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#ifndef __INC_BITSWAP_H
#define __INC_BITSWAP_H
#include "FastLED.h"
FASTLED_NAMESPACE_BEGIN
///@file bitswap.h
///Functions for rotating bits/bytes
///@defgroup Bitswap Bit swapping/rotate
///Functions for doing a rotation of bits/bytes used by parallel output
///@{
#if defined(FASTLED_ARM) || defined(FASTLED_ESP8266)
/// structure representing 8 bits of access
typedef union {
uint8_t raw;
struct {
uint32_t a0:1;
uint32_t a1:1;
uint32_t a2:1;
uint32_t a3:1;
uint32_t a4:1;
uint32_t a5:1;
uint32_t a6:1;
uint32_t a7:1;
};
} just8bits;
/// structure representing 32 bits of access
typedef struct {
uint32_t a0:1;
uint32_t a1:1;
uint32_t a2:1;
uint32_t a3:1;
uint32_t a4:1;
uint32_t a5:1;
uint32_t a6:1;
uint32_t a7:1;
uint32_t b0:1;
uint32_t b1:1;
uint32_t b2:1;
uint32_t b3:1;
uint32_t b4:1;
uint32_t b5:1;
uint32_t b6:1;
uint32_t b7:1;
uint32_t c0:1;
uint32_t c1:1;
uint32_t c2:1;
uint32_t c3:1;
uint32_t c4:1;
uint32_t c5:1;
uint32_t c6:1;
uint32_t c7:1;
uint32_t d0:1;
uint32_t d1:1;
uint32_t d2:1;
uint32_t d3:1;
uint32_t d4:1;
uint32_t d5:1;
uint32_t d6:1;
uint32_t d7:1;
} sub4;
/// union containing a full 8 bytes to swap the bit orientation on
typedef union {
uint32_t word[2];
uint8_t bytes[8];
struct {
sub4 a;
sub4 b;
};
} bitswap_type;
#define SWAPSA(X,N) out. X ## 0 = in.a.a ## N; \
out. X ## 1 = in.a.b ## N; \
out. X ## 2 = in.a.c ## N; \
out. X ## 3 = in.a.d ## N;
#define SWAPSB(X,N) out. X ## 0 = in.b.a ## N; \
out. X ## 1 = in.b.b ## N; \
out. X ## 2 = in.b.c ## N; \
out. X ## 3 = in.b.d ## N;
#define SWAPS(X,N) out. X ## 0 = in.a.a ## N; \
out. X ## 1 = in.a.b ## N; \
out. X ## 2 = in.a.c ## N; \
out. X ## 3 = in.a.d ## N; \
out. X ## 4 = in.b.a ## N; \
out. X ## 5 = in.b.b ## N; \
out. X ## 6 = in.b.c ## N; \
out. X ## 7 = in.b.d ## N;
/// Do an 8byte by 8bit rotation
__attribute__((always_inline)) inline void swapbits8(bitswap_type in, bitswap_type & out) {
// SWAPS(a.a,7);
// SWAPS(a.b,6);
// SWAPS(a.c,5);
// SWAPS(a.d,4);
// SWAPS(b.a,3);
// SWAPS(b.b,2);
// SWAPS(b.c,1);
// SWAPS(b.d,0);
// SWAPSA(a.a,7);
// SWAPSA(a.b,6);
// SWAPSA(a.c,5);
// SWAPSA(a.d,4);
//
// SWAPSB(a.a,7);
// SWAPSB(a.b,6);
// SWAPSB(a.c,5);
// SWAPSB(a.d,4);
//
// SWAPSA(b.a,3);
// SWAPSA(b.b,2);
// SWAPSA(b.c,1);
// SWAPSA(b.d,0);
// //
// SWAPSB(b.a,3);
// SWAPSB(b.b,2);
// SWAPSB(b.c,1);
// SWAPSB(b.d,0);
for(int i = 0; i < 8; i++) {
just8bits work;
work.a3 = in.word[0] >> 31;
work.a2 = in.word[0] >> 23;
work.a1 = in.word[0] >> 15;
work.a0 = in.word[0] >> 7;
in.word[0] <<= 1;
work.a7 = in.word[1] >> 31;
work.a6 = in.word[1] >> 23;
work.a5 = in.word[1] >> 15;
work.a4 = in.word[1] >> 7;
in.word[1] <<= 1;
out.bytes[i] = work.raw;
}
}
/// Slow version of the 8 byte by 8 bit rotation
__attribute__((always_inline)) inline void slowswap(unsigned char *A, unsigned char *B) {
for(int row = 0; row < 7; row++) {
uint8_t x = A[row];
uint8_t bit = (1<<row);
unsigned char *p = B;
for(uint32_t mask = 1<<7 ; mask ; mask >>= 1) {
if(x & mask) {
*p++ |= bit;
} else {
*p++ &= ~bit;
}
}
// B[7] |= (x & 0x01) << row; x >>= 1;
// B[6] |= (x & 0x01) << row; x >>= 1;
// B[5] |= (x & 0x01) << row; x >>= 1;
// B[4] |= (x & 0x01) << row; x >>= 1;
// B[3] |= (x & 0x01) << row; x >>= 1;
// B[2] |= (x & 0x01) << row; x >>= 1;
// B[1] |= (x & 0x01) << row; x >>= 1;
// B[0] |= (x & 0x01) << row; x >>= 1;
}
}
void transpose8x1_noinline(unsigned char *A, unsigned char *B);
/// Simplified form of bits rotating function. Based on code found here - http://www.hackersdelight.org/hdcodetxt/transpose8.c.txt - rotating
/// data into LSB for a faster write (the code using this data can happily walk the array backwards)
__attribute__((always_inline)) inline void transpose8x1(unsigned char *A, unsigned char *B) {
uint32_t x, y, t;
// Load the array and pack it into x and y.
y = *(unsigned int*)(A);
x = *(unsigned int*)(A+4);
// pre-transform x
t = (x ^ (x >> 7)) & 0x00AA00AA; x = x ^ t ^ (t << 7);
t = (x ^ (x >>14)) & 0x0000CCCC; x = x ^ t ^ (t <<14);
// pre-transform y
t = (y ^ (y >> 7)) & 0x00AA00AA; y = y ^ t ^ (t << 7);
t = (y ^ (y >>14)) & 0x0000CCCC; y = y ^ t ^ (t <<14);
// final transform
t = (x & 0xF0F0F0F0) | ((y >> 4) & 0x0F0F0F0F);
y = ((x << 4) & 0xF0F0F0F0) | (y & 0x0F0F0F0F);
x = t;
*((uint32_t*)B) = y;
*((uint32_t*)(B+4)) = x;
}
/// Simplified form of bits rotating function. Based on code found here - http://www.hackersdelight.org/hdcodetxt/transpose8.c.txt
__attribute__((always_inline)) inline void transpose8x1_MSB(unsigned char *A, unsigned char *B) {
uint32_t x, y, t;
// Load the array and pack it into x and y.
y = *(unsigned int*)(A);
x = *(unsigned int*)(A+4);
// pre-transform x
t = (x ^ (x >> 7)) & 0x00AA00AA; x = x ^ t ^ (t << 7);
t = (x ^ (x >>14)) & 0x0000CCCC; x = x ^ t ^ (t <<14);
// pre-transform y
t = (y ^ (y >> 7)) & 0x00AA00AA; y = y ^ t ^ (t << 7);
t = (y ^ (y >>14)) & 0x0000CCCC; y = y ^ t ^ (t <<14);
// final transform
t = (x & 0xF0F0F0F0) | ((y >> 4) & 0x0F0F0F0F);
y = ((x << 4) & 0xF0F0F0F0) | (y & 0x0F0F0F0F);
x = t;
B[7] = y; y >>= 8;
B[6] = y; y >>= 8;
B[5] = y; y >>= 8;
B[4] = y;
B[3] = x; x >>= 8;
B[2] = x; x >>= 8;
B[1] = x; x >>= 8;
B[0] = x; /* */
}
/// templated bit-rotating function. Based on code found here - http://www.hackersdelight.org/hdcodetxt/transpose8.c.txt
template<int m, int n>
__attribute__((always_inline)) inline void transpose8(unsigned char *A, unsigned char *B) {
uint32_t x, y, t;
// Load the array and pack it into x and y.
if(m == 1) {
y = *(unsigned int*)(A);
x = *(unsigned int*)(A+4);
} else {
x = (A[0]<<24) | (A[m]<<16) | (A[2*m]<<8) | A[3*m];
y = (A[4*m]<<24) | (A[5*m]<<16) | (A[6*m]<<8) | A[7*m];
}
// pre-transform x
t = (x ^ (x >> 7)) & 0x00AA00AA; x = x ^ t ^ (t << 7);
t = (x ^ (x >>14)) & 0x0000CCCC; x = x ^ t ^ (t <<14);
// pre-transform y
t = (y ^ (y >> 7)) & 0x00AA00AA; y = y ^ t ^ (t << 7);
t = (y ^ (y >>14)) & 0x0000CCCC; y = y ^ t ^ (t <<14);
// final transform
t = (x & 0xF0F0F0F0) | ((y >> 4) & 0x0F0F0F0F);
y = ((x << 4) & 0xF0F0F0F0) | (y & 0x0F0F0F0F);
x = t;
B[7*n] = y; y >>= 8;
B[6*n] = y; y >>= 8;
B[5*n] = y; y >>= 8;
B[4*n] = y;
B[3*n] = x; x >>= 8;
B[2*n] = x; x >>= 8;
B[n] = x; x >>= 8;
B[0] = x;
// B[0]=x>>24; B[n]=x>>16; B[2*n]=x>>8; B[3*n]=x>>0;
// B[4*n]=y>>24; B[5*n]=y>>16; B[6*n]=y>>8; B[7*n]=y>>0;
}
#endif
FASTLED_NAMESPACE_END
///@}
#endif