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authorDaniel Garcia <danielgarcia@gmail.com>2015-08-11 08:01:41 +0300
committerDaniel Garcia <danielgarcia@gmail.com>2015-08-11 08:01:41 +0300
commit0e2649991468491c1176cc8d8c611846511d7a2c (patch)
tree5a6a7d2d34ccb583ef924f0d979a62c58423a833
parent370694938a185cec533e7816ecbc3e87fdac6bfe (diff)
Start splitting out lib8tion code into separate files, convert documentation format to doxygen as well.
-rw-r--r--docs/Doxyfile2
-rw-r--r--lib8tion.h1102
-rw-r--r--lib8tion/math8.h348
-rw-r--r--lib8tion/random8.h92
-rw-r--r--lib8tion/scale8.h505
-rw-r--r--lib8tion/trig8.h267
6 files changed, 1222 insertions, 1094 deletions
diff --git a/docs/Doxyfile b/docs/Doxyfile
index 71d7b104..52b0e98b 100644
--- a/docs/Doxyfile
+++ b/docs/Doxyfile
@@ -753,7 +753,7 @@ WARN_LOGFILE =
# spaces.
# Note: If this tag is empty the current directory is searched.
-INPUT =
+INPUT = . lib8tion
# This tag can be used to specify the character encoding of the source files
# that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
diff --git a/lib8tion.h b/lib8tion.h
index 87bd8bda..4874aa93 100644
--- a/lib8tion.h
+++ b/lib8tion.h
@@ -288,6 +288,10 @@ Lib8tion is pronounced like 'libation': lie-BAY-shun
#endif
+///@defgroup lib8tion Fast math functions
+///A variety of functions for working with numbers.
+///@{
+
///////////////////////////////////////////////////////////////////////
//
@@ -356,724 +360,17 @@ typedef union {
};
} IEEE754binary32_t;
-
+#include "lib8tion/math8.h"
+#include "lib8tion/scale8.h"
+#include "lib8tion/random8.h"
+#include "lib8tion/trig8.h"
///////////////////////////////////////////////////////////////////////
-// qadd8: add one byte to another, saturating at 0xFF
-LIB8STATIC uint8_t qadd8( uint8_t i, uint8_t j)
-{
-#if QADD8_C == 1
- unsigned int t = i + j;
- if( t > 255) t = 255;
- return t;
-#elif QADD8_AVRASM == 1
- asm volatile(
- /* First, add j to i, conditioning the C flag */
- "add %0, %1 \n\t"
-
- /* Now test the C flag.
- If C is clear, we branch around a load of 0xFF into i.
- If C is set, we go ahead and load 0xFF into i.
- */
- "brcc L_%= \n\t"
- "ldi %0, 0xFF \n\t"
- "L_%=: "
- : "+a" (i)
- : "a" (j) );
- return i;
-#elif QADD8_ARM_DSP_ASM == 1
- asm volatile( "uqadd8 %0, %0, %1" : "+r" (i) : "r" (j));
- return i;
-#else
-#error "No implementation for qadd8 available."
-#endif
-}
-
-
-// qadd7: add one signed byte to another,
-// saturating at 0x7F.
-LIB8STATIC int8_t qadd7( int8_t i, int8_t j)
-{
-#if QADD7_C == 1
- int16_t t = i + j;
- if( t > 127) t = 127;
- return t;
-#elif QADD7_AVRASM == 1
- asm volatile(
- /* First, add j to i, conditioning the V flag */
- "add %0, %1 \n\t"
-
- /* Now test the V flag.
- If V is clear, we branch around a load of 0x7F into i.
- If V is set, we go ahead and load 0x7F into i.
- */
- "brvc L_%= \n\t"
- "ldi %0, 0x7F \n\t"
- "L_%=: "
- : "+a" (i)
- : "a" (j) );
-
- return i;
-#elif QADD7_ARM_DSP_ASM == 1
- asm volatile( "qadd8 %0, %0, %1" : "+r" (i) : "r" (j));
- return i;
-#else
-#error "No implementation for qadd7 available."
-#endif
-}
-
-// qsub8: subtract one byte from another, saturating at 0x00
-LIB8STATIC uint8_t qsub8( uint8_t i, uint8_t j)
-{
-#if QSUB8_C == 1
- int t = i - j;
- if( t < 0) t = 0;
- return t;
-#elif QSUB8_AVRASM == 1
-
- asm volatile(
- /* First, subtract j from i, conditioning the C flag */
- "sub %0, %1 \n\t"
-
- /* Now test the C flag.
- If C is clear, we branch around a load of 0x00 into i.
- If C is set, we go ahead and load 0x00 into i.
- */
- "brcc L_%= \n\t"
- "ldi %0, 0x00 \n\t"
- "L_%=: "
- : "+a" (i)
- : "a" (j) );
-
- return i;
-#else
-#error "No implementation for qsub8 available."
-#endif
-}
-
-// add8: add one byte to another, with one byte result
-LIB8STATIC uint8_t add8( uint8_t i, uint8_t j)
-{
-#if ADD8_C == 1
- int t = i + j;
- return t;
-#elif ADD8_AVRASM == 1
- // Add j to i, period.
- asm volatile( "add %0, %1" : "+a" (i) : "a" (j));
- return i;
-#else
-#error "No implementation for add8 available."
-#endif
-}
-
-
-// sub8: subtract one byte from another, 8-bit result
-LIB8STATIC uint8_t sub8( uint8_t i, uint8_t j)
-{
-#if SUB8_C == 1
- int t = i - j;
- return t;
-#elif SUB8_AVRASM == 1
- // Subtract j from i, period.
- asm volatile( "sub %0, %1" : "+a" (i) : "a" (j));
- return i;
-#else
-#error "No implementation for sub8 available."
-#endif
-}
-
-// avg8: Calculate an integer average of two unsigned
-// 8-bit integer values (uint8_t).
-// Fractional results are rounded down, e.g. avg8(20,41) = 30
-LIB8STATIC uint8_t avg8( uint8_t i, uint8_t j)
-{
-#if AVG8_C == 1
- return (i + j) >> 1;
-#elif AVG8_AVRASM == 1
- asm volatile(
- /* First, add j to i, 9th bit overflows into C flag */
- "add %0, %1 \n\t"
- /* Divide by two, moving C flag into high 8th bit */
- "ror %0 \n\t"
- : "+a" (i)
- : "a" (j) );
- return i;
-#else
-#error "No implementation for avg8 available."
-#endif
-}
-
-
-// avg7: Calculate an integer average of two signed 7-bit
-// integers (int8_t)
-// If the first argument is even, result is rounded down.
-// If the first argument is odd, result is result up.
-LIB8STATIC int8_t avg7( int8_t i, int8_t j)
-{
-#if AVG7_C == 1
- return ((i + j) >> 1) + (i & 0x1);
-#elif AVG7_AVRASM == 1
- asm volatile(
- "asr %1 \n\t"
- "asr %0 \n\t"
- "adc %0, %1 \n\t"
- : "+a" (i)
- : "a" (j) );
- return i;
-#else
-#error "No implementation for avg7 available."
-#endif
-}
-
-// mod8: Calculate the remainder of one unsigned 8-bit
-// value divided by anoter, aka A % M.
-// Implemented by repeated subtraction, which is
-// very compact, and very fast if A is 'probably'
-// less than M. If A is a large multiple of M,
-// the loop has to execute multiple times. However,
-// even in that case, the loop is only two
-// instructions long on AVR, i.e., quick.
-LIB8STATIC uint8_t mod8( uint8_t a, uint8_t m)
-{
-#if defined(__AVR__)
- asm volatile (
- "L_%=: sub %[a],%[m] \n\t"
- " brcc L_%= \n\t"
- " add %[a],%[m] \n\t"
- : [a] "+r" (a)
- : [m] "r" (m)
- );
-#else
- while( a >= m) a -= m;
-#endif
- return a;
-}
-
-// addmod8: Add two numbers, and calculate the modulo
-// of the sum and a third number, M.
-// In other words, it returns (A+B) % M.
-// It is designed as a compact mechanism for
-// incrementing a 'mode' switch and wrapping
-// around back to 'mode 0' when the switch
-// goes past the end of the available range.
-// e.g. if you have seven modes, this switches
-// to the next one and wraps around if needed:
-// mode = addmod8( mode, 1, 7);
-// See 'mod8' for notes on performance.
-LIB8STATIC uint8_t addmod8( uint8_t a, uint8_t b, uint8_t m)
-{
-#if defined(__AVR__)
- asm volatile (
- " add %[a],%[b] \n\t"
- "L_%=: sub %[a],%[m] \n\t"
- " brcc L_%= \n\t"
- " add %[a],%[m] \n\t"
- : [a] "+r" (a)
- : [b] "r" (b), [m] "r" (m)
- );
-#else
- a += b;
- while( a >= m) a -= m;
-#endif
- return a;
-}
-
-
-// scale8: scale one byte by a second one, which is treated as
-// the numerator of a fraction whose denominator is 256
-// In other words, it computes i * (scale / 256)
-// 4 clocks AVR with MUL, 2 clocks ARM
-LIB8STATIC uint8_t scale8( uint8_t i, fract8 scale)
-{
-#if SCALE8_C == 1
- return ((uint16_t)i * (uint16_t)(scale) ) >> 8;
-#elif SCALE8_AVRASM == 1
-#if defined(LIB8_ATTINY)
- uint8_t work=0;
- uint8_t cnt=0x80;
- asm volatile(
- "LOOP_%=: \n\t"
- /*" sbrc %[scale], 0 \n\t"
- " add %[work], %[i] \n\t"
- " ror %[work] \n\t"
- " lsr %[scale] \n\t"
- " clc \n\t"*/
- " sbrc %[scale], 0 \n\t"
- " add %[work], %[i] \n\t"
- " ror %[work] \n\t"
- " lsr %[scale] \n\t"
- " lsr %[cnt] \n\t"
- "brcc LOOP_%="
- : [work] "+r" (work), [cnt] "+r" (cnt)
- : [scale] "r" (scale), [i] "r" (i)
- :
- );
- return work;
-#else
- asm volatile(
- /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
- "mul %0, %1 \n\t"
- /* Move the high 8-bits of the product (r1) back to i */
- "mov %0, r1 \n\t"
- /* Restore r1 to "0"; it's expected to always be that */
- "clr __zero_reg__ \n\t"
-
- : "+a" (i) /* writes to i */
- : "a" (scale) /* uses scale */
- : "r0", "r1" /* clobbers r0, r1 */ );
-
- /* Return the result */
- return i;
-#endif
-#else
-#error "No implementation for scale8 available."
-#endif
-}
-
-
-// The "video" version of scale8 guarantees that the output will
-// be only be zero if one or both of the inputs are zero. If both
-// inputs are non-zero, the output is guaranteed to be non-zero.
-// This makes for better 'video'/LED dimming, at the cost of
-// several additional cycles.
-LIB8STATIC uint8_t scale8_video( uint8_t i, fract8 scale)
-{
-#if SCALE8_C == 1 || defined(LIB8_ATTINY)
- uint8_t j = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
- // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- // uint8_t j = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
- return j;
-#elif SCALE8_AVRASM == 1
- uint8_t j=0;
- asm volatile(
- " tst %[i]\n\t"
- " breq L_%=\n\t"
- " mul %[i], %[scale]\n\t"
- " mov %[j], r1\n\t"
- " clr __zero_reg__\n\t"
- " cpse %[scale], r1\n\t"
- " subi %[j], 0xFF\n\t"
- "L_%=: \n\t"
- : [j] "+a" (j)
- : [i] "a" (i), [scale] "a" (scale)
- : "r0", "r1");
-
- return j;
- // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- // asm volatile(
- // " tst %0 \n"
- // " breq L_%= \n"
- // " mul %0, %1 \n"
- // " mov %0, r1 \n"
- // " add %0, %2 \n"
- // " clr __zero_reg__ \n"
- // "L_%=: \n"
-
- // : "+a" (i)
- // : "a" (scale), "a" (nonzeroscale)
- // : "r0", "r1");
-
- // // Return the result
- // return i;
-#else
-#error "No implementation for scale8_video available."
-#endif
-}
-
-
-// This version of scale8 does not clean up the R1 register on AVR
-// If you are doing several 'scale8's in a row, use this, and
-// then explicitly call cleanup_R1.
-LIB8STATIC uint8_t scale8_LEAVING_R1_DIRTY( uint8_t i, fract8 scale)
-{
-#if SCALE8_C == 1
- return ((int)i * (int)(scale) ) >> 8;
-#elif SCALE8_AVRASM == 1
- asm volatile(
- /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
- "mul %0, %1 \n\t"
- /* Move the high 8-bits of the product (r1) back to i */
- "mov %0, r1 \n\t"
- /* R1 IS LEFT DIRTY HERE; YOU MUST ZERO IT OUT YOURSELF */
- /* "clr __zero_reg__ \n\t" */
-
- : "+a" (i) /* writes to i */
- : "a" (scale) /* uses scale */
- : "r0", "r1" /* clobbers r0, r1 */ );
-
- // Return the result
- return i;
-#else
-#error "No implementation for scale8_LEAVING_R1_DIRTY available."
-#endif
-}
-
-// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENT DIRECTLY IN PLACE
-
-LIB8STATIC void nscale8_LEAVING_R1_DIRTY( uint8_t& i, fract8 scale)
-{
-#if SCALE8_C == 1
- i = ((int)i * (int)(scale) ) >> 8;
-#elif SCALE8_AVRASM == 1
- asm volatile(
- /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
- "mul %0, %1 \n\t"
- /* Move the high 8-bits of the product (r1) back to i */
- "mov %0, r1 \n\t"
- /* R1 IS LEFT DIRTY HERE; YOU MUST ZERO IT OUT YOURSELF */
- /* "clr __zero_reg__ \n\t" */
-
- : "+a" (i) /* writes to i */
- : "a" (scale) /* uses scale */
- : "r0", "r1" /* clobbers r0, r1 */ );
-#else
-#error "No implementation for nscale8_LEAVING_R1_DIRTY available."
-#endif
-}
-
-
-
-LIB8STATIC uint8_t scale8_video_LEAVING_R1_DIRTY( uint8_t i, fract8 scale)
-{
-#if SCALE8_C == 1 || defined(LIB8_ATTINY)
- uint8_t j = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
- // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- // uint8_t j = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
- return j;
-#elif SCALE8_AVRASM == 1
- uint8_t j=0;
- asm volatile(
- " tst %[i]\n\t"
- " breq L_%=\n\t"
- " mul %[i], %[scale]\n\t"
- " mov %[j], r1\n\t"
- " breq L_%=\n\t"
- " subi %[j], 0xFF\n\t"
- "L_%=: \n\t"
- : [j] "+a" (j)
- : [i] "a" (i), [scale] "a" (scale)
- : "r0", "r1");
-
- return j;
- // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- // asm volatile(
- // " tst %0 \n"
- // " breq L_%= \n"
- // " mul %0, %1 \n"
- // " mov %0, r1 \n"
- // " add %0, %2 \n"
- // " clr __zero_reg__ \n"
- // "L_%=: \n"
-
- // : "+a" (i)
- // : "a" (scale), "a" (nonzeroscale)
- // : "r0", "r1");
-
- // // Return the result
- // return i;
-#else
-#error "No implementation for scale8_video_LEAVING_R1_DIRTY available."
-#endif
-}
-
-LIB8STATIC void nscale8_video_LEAVING_R1_DIRTY( uint8_t & i, fract8 scale)
-{
-#if SCALE8_C == 1 || defined(LIB8_ATTINY)
- i = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
-#elif SCALE8_AVRASM == 1
- asm volatile(
- " tst %[i]\n\t"
- " breq L_%=\n\t"
- " mul %[i], %[scale]\n\t"
- " mov %[i], r1\n\t"
- " breq L_%=\n\t"
- " subi %[i], 0xFF\n\t"
- "L_%=: \n\t"
- : [i] "+a" (i)
- : [scale] "a" (scale)
- : "r0", "r1");
-#else
-#error "No implementation for scale8_video_LEAVING_R1_DIRTY available."
-#endif
-}
-
-
-LIB8STATIC void cleanup_R1()
-{
-#if CLEANUP_R1_AVRASM == 1
- // Restore r1 to "0"; it's expected to always be that
- asm volatile( "clr __zero_reg__ \n\t" : : : "r1" );
-#endif
-}
-
-
-// nscale8x3: scale three one byte values by a fourth one, which is treated as
-// the numerator of a fraction whose demominator is 256
-// In other words, it computes r,g,b * (scale / 256)
-//
-// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
-
-LIB8STATIC void nscale8x3( uint8_t& r, uint8_t& g, uint8_t& b, fract8 scale)
-{
-#if SCALE8_C == 1
- r = ((int)r * (int)(scale) ) >> 8;
- g = ((int)g * (int)(scale) ) >> 8;
- b = ((int)b * (int)(scale) ) >> 8;
-#elif SCALE8_AVRASM == 1
- r = scale8_LEAVING_R1_DIRTY(r, scale);
- g = scale8_LEAVING_R1_DIRTY(g, scale);
- b = scale8_LEAVING_R1_DIRTY(b, scale);
- cleanup_R1();
-#else
-#error "No implementation for nscale8x3 available."
-#endif
-}
-
-
-LIB8STATIC void nscale8x3_video( uint8_t& r, uint8_t& g, uint8_t& b, fract8 scale)
-{
-#if SCALE8_C == 1
- uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- r = (r == 0) ? 0 : (((int)r * (int)(scale) ) >> 8) + nonzeroscale;
- g = (g == 0) ? 0 : (((int)g * (int)(scale) ) >> 8) + nonzeroscale;
- b = (b == 0) ? 0 : (((int)b * (int)(scale) ) >> 8) + nonzeroscale;
-#elif SCALE8_AVRASM == 1
- nscale8_video_LEAVING_R1_DIRTY( r, scale);
- nscale8_video_LEAVING_R1_DIRTY( g, scale);
- nscale8_video_LEAVING_R1_DIRTY( b, scale);
- cleanup_R1();
-#else
-#error "No implementation for nscale8x3 available."
-#endif
-}
-// nscale8x2: scale two one byte values by a third one, which is treated as
-// the numerator of a fraction whose demominator is 256
-// In other words, it computes i,j * (scale / 256)
-//
-// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
-LIB8STATIC void nscale8x2( uint8_t& i, uint8_t& j, fract8 scale)
-{
-#if SCALE8_C == 1
- i = ((int)i * (int)(scale) ) >> 8;
- j = ((int)j * (int)(scale) ) >> 8;
-#elif SCALE8_AVRASM == 1
- i = scale8_LEAVING_R1_DIRTY(i, scale);
- j = scale8_LEAVING_R1_DIRTY(j, scale);
- cleanup_R1();
-#else
-#error "No implementation for nscale8x2 available."
-#endif
-}
-LIB8STATIC void nscale8x2_video( uint8_t& i, uint8_t& j, fract8 scale)
-{
-#if SCALE8_C == 1
- uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
- i = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
- j = (j == 0) ? 0 : (((int)j * (int)(scale) ) >> 8) + nonzeroscale;
-#elif SCALE8_AVRASM == 1
- nscale8_video_LEAVING_R1_DIRTY( i, scale);
- nscale8_video_LEAVING_R1_DIRTY( j, scale);
- cleanup_R1();
-#else
-#error "No implementation for nscale8x2 available."
-#endif
-}
-
-
-// scale16by8: scale a 16-bit unsigned value by an 8-bit value,
-// considered as numerator of a fraction whose denominator
-// is 256. In other words, it computes i * (scale / 256)
-
-#if SCALE16BY8_C == 1
-LIB8STATIC uint16_t scale16by8( uint16_t i, fract8 scale )
-{
- uint16_t result;
- result = (i * scale) / 256;
- return result;
-}
-#elif SCALE16BY8_AVRASM == 1
-LIB8STATIC uint16_t scale16by8( uint16_t i, fract8 scale )
-{
- uint16_t result = 0;
- asm volatile(
- // result.A = HighByte(i.A x j )
- " mul %A[i], %[scale] \n\t"
- " mov %A[result], r1 \n\t"
- //" clr %B[result] \n\t"
-
- // result.A-B += i.B x j
- " mul %B[i], %[scale] \n\t"
- " add %A[result], r0 \n\t"
- " adc %B[result], r1 \n\t"
-
- // cleanup r1
- " clr __zero_reg__ \n\t"
-
- : [result] "+r" (result)
- : [i] "r" (i), [scale] "r" (scale)
- : "r0", "r1"
- );
- return result;
-}
-#else
-#error "No implementation for scale16by8 available."
-#endif
-
-// scale16: scale a 16-bit unsigned value by a 16-bit value,
-// considered as numerator of a fraction whose denominator
-// is 65536. In other words, it computes i * (scale / 65536)
-
-#if SCALE16_C == 1
-LIB8STATIC uint16_t scale16( uint16_t i, fract16 scale )
-{
- uint16_t result;
- result = ((uint32_t)(i) * (uint32_t)(scale)) / 65536;
- return result;
-}
-#elif SCALE16_AVRASM == 1
-LIB8STATIC uint16_t scale16( uint16_t i, fract16 scale )
-{
- uint32_t result = 0;
- const uint8_t zero = 0;
- asm volatile(
- // result.A-B = i.A x scale.A
- " mul %A[i], %A[scale] \n\t"
- // save results...
- // basic idea:
- //" mov %A[result], r0 \n\t"
- //" mov %B[result], r1 \n\t"
- // which can be written as...
- " movw %A[result], r0 \n\t"
- // We actually need to do anything with r0,
- // as result.A is never used again here, so we
- // could just move the high byte, but movw is
- // one clock cycle, just like mov, so might as
- // well, in case we want to use this code for
- // a generic 16x16 multiply somewhere.
-
- // result.C-D = i.B x scale.B
- " mul %B[i], %B[scale] \n\t"
- //" mov %C[result], r0 \n\t"
- //" mov %D[result], r1 \n\t"
- " movw %C[result], r0 \n\t"
-
- // result.B-D += i.B x scale.A
- " mul %B[i], %A[scale] \n\t"
-
- " add %B[result], r0 \n\t"
- " adc %C[result], r1 \n\t"
- " adc %D[result], %[zero] \n\t"
-
- // result.B-D += i.A x scale.B
- " mul %A[i], %B[scale] \n\t"
-
- " add %B[result], r0 \n\t"
- " adc %C[result], r1 \n\t"
- " adc %D[result], %[zero] \n\t"
-
- // cleanup r1
- " clr r1 \n\t"
-
- : [result] "+r" (result)
- : [i] "r" (i),
- [scale] "r" (scale),
- [zero] "r" (zero)
- : "r0", "r1"
- );
- result = result >> 16;
- return result;
-}
-#else
-#error "No implementation for scale16 available."
-#endif
-
-
-
-// mul8: 8x8 bit multiplication, with 8 bit result
-LIB8STATIC uint8_t mul8( uint8_t i, uint8_t j)
-{
-#if MUL8_C == 1
- return ((int)i * (int)(j) ) & 0xFF;
-#elif MUL8_AVRASM == 1
- asm volatile(
- /* Multiply 8-bit i * 8-bit j, giving 16-bit r1,r0 */
- "mul %0, %1 \n\t"
- /* Extract the LOW 8-bits (r0) */
- "mov %0, r0 \n\t"
- /* Restore r1 to "0"; it's expected to always be that */
- "clr __zero_reg__ \n\t"
- : "+a" (i)
- : "a" (j)
- : "r0", "r1");
-
- return i;
-#else
-#error "No implementation for mul8 available."
-#endif
-}
-
-
-// mul8: saturating 8x8 bit multiplication, with 8 bit result
-LIB8STATIC uint8_t qmul8( uint8_t i, uint8_t j)
-{
-#if QMUL8_C == 1
- int p = ((int)i * (int)(j) );
- if( p > 255) p = 255;
- return p;
-#elif QMUL8_AVRASM == 1
- asm volatile(
- /* Multiply 8-bit i * 8-bit j, giving 16-bit r1,r0 */
- " mul %0, %1 \n\t"
- /* If high byte of result is zero, all is well. */
- " tst r1 \n\t"
- " breq Lnospill_%= \n\t"
- /* If high byte of result > 0, saturate low byte to 0xFF */
- " ldi %0,0xFF \n\t"
- " rjmp Ldone_%= \n\t"
- "Lnospill_%=: \n\t"
- /* Extract the LOW 8-bits (r0) */
- " mov %0, r0 \n\t"
- "Ldone_%=: \n\t"
- /* Restore r1 to "0"; it's expected to always be that */
- " clr __zero_reg__ \n\t"
- : "+a" (i)
- : "a" (j)
- : "r0", "r1");
-
- return i;
-#else
-#error "No implementation for qmul8 available."
-#endif
-}
-
-
-// abs8: take abs() of a signed 8-bit uint8_t
-LIB8STATIC int8_t abs8( int8_t i)
-{
-#if ABS8_C == 1
- if( i < 0) i = -i;
- return i;
-#elif ABS8_AVRASM == 1
-
-
- asm volatile(
- /* First, check the high bit, and prepare to skip if it's clear */
- "sbrc %0, 7 \n"
-
- /* Negate the value */
- "neg %0 \n"
-
- : "+r" (i) : "r" (i) );
- return i;
-#else
-#error "No implementation for abs8 available."
-#endif
-}
///////////////////////////////////////////////////////////////////////
@@ -1103,355 +400,6 @@ LIB8STATIC sfract15 floatToSfract15( float f)
///////////////////////////////////////////////////////////////////////
-
-// Dimming and brightening functions
-//
-// The eye does not respond in a linear way to light.
-// High speed PWM'd LEDs at 50% duty cycle appear far
-// brighter then the 'half as bright' you might expect.
-//
-// If you want your midpoint brightness leve (128) to
-// appear half as bright as 'full' brightness (255), you
-// have to apply a 'dimming function'.
-//
-//
-
-LIB8STATIC uint8_t dim8_raw( uint8_t x)
-{
- return scale8( x, x);
-}
-
-LIB8STATIC uint8_t dim8_video( uint8_t x)
-{
- return scale8_video( x, x);
-}
-
-LIB8STATIC uint8_t dim8_lin( uint8_t x )
-{
- if( x & 0x80 ) {
- x = scale8( x, x);
- } else {
- x += 1;
- x /= 2;
- }
- return x;
-}
-
-LIB8STATIC uint8_t brighten8_raw( uint8_t x)
-{
- uint8_t ix = 255 - x;
- return 255 - scale8( ix, ix);
-}
-
-LIB8STATIC uint8_t brighten8_video( uint8_t x)
-{
- uint8_t ix = 255 - x;
- return 255 - scale8_video( ix, ix);
-}
-
-LIB8STATIC uint8_t brighten8_lin( uint8_t x )
-{
- uint8_t ix = 255 - x;
- if( ix & 0x80 ) {
- ix = scale8( ix, ix);
- } else {
- ix += 1;
- ix /= 2;
- }
- return 255 - ix;
-}
-
-///////////////////////////////////////////////////////////////////////
-
-// A 16-bit PNRG good enough for LED animations
-
-// X(n+1) = (2053 * X(n)) + 13849)
-#define FASTLED_RAND16_2053 ((uint16_t)(2053))
-#define FASTLED_RAND16_13849 ((uint16_t)(13849))
-
-extern uint16_t rand16seed;// = RAND16_SEED;
-
-
-LIB8STATIC uint8_t random8()
-{
- rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
- // return the sum of the high and low bytes, for better
- // mixing and non-sequential correlation
- return (uint8_t)(((uint8_t)(rand16seed & 0xFF)) +
- ((uint8_t)(rand16seed >> 8)));
-}
-
-LIB8STATIC uint16_t random16()
-{
- rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
- return rand16seed;
-}
-
-
-LIB8STATIC uint8_t random8(uint8_t lim)
-{
- uint8_t r = random8();
- r = scale8( r, lim);
- return r;
-}
-
-LIB8STATIC uint8_t random8(uint8_t min, uint8_t lim)
-{
- uint8_t delta = lim - min;
- uint8_t r = random8(delta) + min;
- return r;
-}
-
-LIB8STATIC uint16_t random16( uint16_t lim)
-{
- uint16_t r = random16();
- uint32_t p = (uint32_t)lim * (uint32_t)r;
- r = p >> 16;
- return r;
-}
-
-LIB8STATIC uint16_t random16( uint16_t min, uint16_t lim)
-{
- uint16_t delta = lim - min;
- uint16_t r = random16( delta) + min;
- return r;
-}
-
-LIB8STATIC void random16_set_seed( uint16_t seed)
-{
- rand16seed = seed;
-}
-
-LIB8STATIC uint16_t random16_get_seed()
-{
- return rand16seed;
-}
-
-LIB8STATIC void random16_add_entropy( uint16_t entropy)
-{
- rand16seed += entropy;
-}
-
-
-///////////////////////////////////////////////////////////////////////
-
-// sin16 & cos16:
-// Fast 16-bit approximations of sin(x) & cos(x).
-// Input angle is an unsigned int from 0-65535.
-// Output is signed int from -32767 to 32767.
-//
-// This approximation never varies more than 0.69%
-// from the floating point value you'd get by doing
-// float s = sin( x ) * 32767.0;
-//
-// Don't use this approximation for calculating the
-// trajectory of a rocket to Mars, but it's great
-// for art projects and LED displays.
-//
-// On Arduino/AVR, this approximation is more than
-// 10X faster than floating point sin(x) and cos(x)
-
-#if defined(__AVR__)
-#define sin16 sin16_avr
-#else
-#define sin16 sin16_C
-#endif
-
-LIB8STATIC int16_t sin16_avr( uint16_t theta )
-{
- static const uint8_t data[] =
- { 0, 0, 49, 0, 6393%256, 6393/256, 48, 0,
- 12539%256, 12539/256, 44, 0, 18204%256, 18204/256, 38, 0,
- 23170%256, 23170/256, 31, 0, 27245%256, 27245/256, 23, 0,
- 30273%256, 30273/256, 14, 0, 32137%256, 32137/256, 4 /*,0*/ };
-
- uint16_t offset = (theta & 0x3FFF);
-
- // AVR doesn't have a multi-bit shift instruction,
- // so if we say "offset >>= 3", gcc makes a tiny loop.
- // Inserting empty volatile statements between each
- // bit shift forces gcc to unroll the loop.
- offset >>= 1; // 0..8191
- asm volatile("");
- offset >>= 1; // 0..4095
- asm volatile("");
- offset >>= 1; // 0..2047
-
- if( theta & 0x4000 ) offset = 2047 - offset;
-
- uint8_t sectionX4;
- sectionX4 = offset / 256;
- sectionX4 *= 4;
-
- uint8_t m;
-
- union {
- uint16_t b;
- struct {
- uint8_t blo;
- uint8_t bhi;
- };
- } u;
-
- //in effect u.b = blo + (256 * bhi);
- u.blo = data[ sectionX4 ];
- u.bhi = data[ sectionX4 + 1];
- m = data[ sectionX4 + 2];
-
- uint8_t secoffset8 = (uint8_t)(offset) / 2;
-
- uint16_t mx = m * secoffset8;
-
- int16_t y = mx + u.b;
- if( theta & 0x8000 ) y = -y;
-
- return y;
-}
-
-LIB8STATIC int16_t sin16_C( uint16_t theta )
-{
- static const uint16_t base[] =
- { 0, 6393, 12539, 18204, 23170, 27245, 30273, 32137 };
- static const uint8_t slope[] =
- { 49, 48, 44, 38, 31, 23, 14, 4 };
-
- uint16_t offset = (theta & 0x3FFF) >> 3; // 0..2047
- if( theta & 0x4000 ) offset = 2047 - offset;
-
- uint8_t section = offset / 256; // 0..7
- uint16_t b = base[section];
- uint8_t m = slope[section];
-
- uint8_t secoffset8 = (uint8_t)(offset) / 2;
-
- uint16_t mx = m * secoffset8;
- int16_t y = mx + b;
-
- if( theta & 0x8000 ) y = -y;
-
- return y;
-}
-
-LIB8STATIC int16_t cos16( uint16_t theta)
-{
- return sin16( theta + 16384);
-}
-
-///////////////////////////////////////////////////////////////////////
-
-// sin8 & cos8
-// Fast 8-bit approximations of sin(x) & cos(x).
-// Input angle is an unsigned int from 0-255.
-// Output is an unsigned int from 0 to 255.
-//
-// This approximation can vary to to 2%
-// from the floating point value you'd get by doing
-// float s = (sin( x ) * 128.0) + 128;
-//
-// Don't use this approximation for calculating the
-// "real" trigonometric calculations, but it's great
-// for art projects and LED displays.
-//
-// On Arduino/AVR, this approximation is more than
-// 20X faster than floating point sin(x) and cos(x)
-
-#if defined(__AVR__) && !defined(LIB8_ATTINY)
-#define sin8 sin8_avr
-#else
-#define sin8 sin8_C
-#endif
-
-
-const uint8_t b_m16_interleave[] = { 0, 49, 49, 41, 90, 27, 117, 10 };
-
-LIB8STATIC uint8_t sin8_avr( uint8_t theta)
-{
- uint8_t offset = theta;
-
- asm volatile(
- "sbrc %[theta],6 \n\t"
- "com %[offset] \n\t"
- : [theta] "+r" (theta), [offset] "+r" (offset)
- );
-
- offset &= 0x3F; // 0..63
-
- uint8_t secoffset = offset & 0x0F; // 0..15
- if( theta & 0x40) secoffset++;
-
- uint8_t m16; uint8_t b;
-
- uint8_t section = offset >> 4; // 0..3
- uint8_t s2 = section * 2;
-
- const uint8_t* p = b_m16_interleave;
- p += s2;
- b = *p;
- p++;
- m16 = *p;
-
- uint8_t mx;
- uint8_t xr1;
- asm volatile(
- "mul %[m16],%[secoffset] \n\t"
- "mov %[mx],r0 \n\t"
- "mov %[xr1],r1 \n\t"
- "eor r1, r1 \n\t"
- "swap %[mx] \n\t"
- "andi %[mx],0x0F \n\t"
- "swap %[xr1] \n\t"
- "andi %[xr1], 0xF0 \n\t"
- "or %[mx], %[xr1] \n\t"
- : [mx] "=r" (mx), [xr1] "=r" (xr1)
- : [m16] "r" (m16), [secoffset] "r" (secoffset)
- );
-
- int8_t y = mx + b;
- if( theta & 0x80 ) y = -y;
-
- y += 128;
-
- return y;
-}
-
-
-LIB8STATIC uint8_t sin8_C( uint8_t theta)
-{
- uint8_t offset = theta;
- if( theta & 0x40 ) {
- offset = (uint8_t)255 - offset;
- }
- offset &= 0x3F; // 0..63
-
- uint8_t secoffset = offset & 0x0F; // 0..15
- if( theta & 0x40) secoffset++;
-
- uint8_t section = offset >> 4; // 0..3
- uint8_t s2 = section * 2;
- const uint8_t* p = b_m16_interleave;
- p += s2;
- uint8_t b = *p;
- p++;
- uint8_t m16 = *p;
-
- uint8_t mx = (m16 * secoffset) >> 4;
-
- int8_t y = mx + b;
- if( theta & 0x80 ) y = -y;
-
- y += 128;
-
- return y;
-}
-
-
-LIB8STATIC uint8_t cos8( uint8_t theta)
-{
- return sin8( theta + 64);
-}
-
-
-///////////////////////////////////////////////////////////////////////
//
// memmove8, memcpy8, and memset8:
// alternatives to memmove, memcpy, and memset that are
@@ -1770,39 +718,6 @@ LIB8STATIC uint8_t squarewave8( uint8_t in, uint8_t pulsewidth=128)
-// sqrt16: square root for 16-bit integers
-// About three times faster and five times smaller
-// than Arduino's general sqrt on AVR.
-LIB8STATIC uint8_t sqrt16(uint16_t x)
-{
- if( x <= 1) {
- return x;
- }
-
- uint8_t low = 1; // lower bound
- uint8_t hi, mid;
-
- if( x > 7904) {
- hi = 255;
- } else {
- hi = (x >> 5) + 8; // initial estimate for upper bound
- }
-
- do {
- mid = (low + hi) >> 1;
- if ((uint16_t)(mid * mid) > x) {
- hi = mid - 1;
- } else {
- if( mid == 255) {
- return 255;
- }
- low = mid + 1;
- }
- } while (hi >= low);
-
- return low - 1;
-}
-
template<class T, int F, int I> class q {
T i:I;
@@ -2136,5 +1051,6 @@ typedef CEveryNTimePeriods<uint8_t,hours8> CEveryNHours;
#define EVERY_N_MILLISECONDS(N) EVERY_N_MILLIS(N)
FASTLED_NAMESPACE_END
+///@}
#endif
diff --git a/lib8tion/math8.h b/lib8tion/math8.h
new file mode 100644
index 00000000..9f1e9256
--- /dev/null
+++ b/lib8tion/math8.h
@@ -0,0 +1,348 @@
+#ifndef __INC_LIB8TION_MATH_H
+#define __INC_LIB8TION_MATH_H
+
+///@ingroup lib8tion
+
+///@defgroup Math Basic math operations
+///@{
+/// add one byte to another, saturating at 0xFF
+/// @param i - first byte to add
+/// @param j - second byte to add
+/// @returns the sum of i & j, capped at 0xFF
+LIB8STATIC uint8_t qadd8( uint8_t i, uint8_t j)
+{
+#if QADD8_C == 1
+ unsigned int t = i + j;
+ if( t > 255) t = 255;
+ return t;
+#elif QADD8_AVRASM == 1
+ asm volatile(
+ /* First, add j to i, conditioning the C flag */
+ "add %0, %1 \n\t"
+
+ /* Now test the C flag.
+ If C is clear, we branch around a load of 0xFF into i.
+ If C is set, we go ahead and load 0xFF into i.
+ */
+ "brcc L_%= \n\t"
+ "ldi %0, 0xFF \n\t"
+ "L_%=: "
+ : "+a" (i)
+ : "a" (j) );
+ return i;
+#elif QADD8_ARM_DSP_ASM == 1
+ asm volatile( "uqadd8 %0, %0, %1" : "+r" (i) : "r" (j));
+ return i;
+#else
+#error "No implementation for qadd8 available."
+#endif
+}
+
+/// Add one byte to another, saturating at 0x7F
+/// @param i - first byte to add
+/// @param j - second byte to add
+/// @returns the sum of i & j, capped at 0xFF
+LIB8STATIC int8_t qadd7( int8_t i, int8_t j)
+{
+#if QADD7_C == 1
+ int16_t t = i + j;
+ if( t > 127) t = 127;
+ return t;
+#elif QADD7_AVRASM == 1
+ asm volatile(
+ /* First, add j to i, conditioning the V flag */
+ "add %0, %1 \n\t"
+
+ /* Now test the V flag.
+ If V is clear, we branch around a load of 0x7F into i.
+ If V is set, we go ahead and load 0x7F into i.
+ */
+ "brvc L_%= \n\t"
+ "ldi %0, 0x7F \n\t"
+ "L_%=: "
+ : "+a" (i)
+ : "a" (j) );
+
+ return i;
+#elif QADD7_ARM_DSP_ASM == 1
+ asm volatile( "qadd8 %0, %0, %1" : "+r" (i) : "r" (j));
+ return i;
+#else
+#error "No implementation for qadd7 available."
+#endif
+}
+
+/// subtract one byte from another, saturating at 0x00
+/// @returns i - j with a floor of 0
+LIB8STATIC uint8_t qsub8( uint8_t i, uint8_t j)
+{
+#if QSUB8_C == 1
+ int t = i - j;
+ if( t < 0) t = 0;
+ return t;
+#elif QSUB8_AVRASM == 1
+
+ asm volatile(
+ /* First, subtract j from i, conditioning the C flag */
+ "sub %0, %1 \n\t"
+
+ /* Now test the C flag.
+ If C is clear, we branch around a load of 0x00 into i.
+ If C is set, we go ahead and load 0x00 into i.
+ */
+ "brcc L_%= \n\t"
+ "ldi %0, 0x00 \n\t"
+ "L_%=: "
+ : "+a" (i)
+ : "a" (j) );
+
+ return i;
+#else
+#error "No implementation for qsub8 available."
+#endif
+}
+
+/// add one byte to another, with one byte result
+LIB8STATIC uint8_t add8( uint8_t i, uint8_t j)
+{
+#if ADD8_C == 1
+ int t = i + j;
+ return t;
+#elif ADD8_AVRASM == 1
+ // Add j to i, period.
+ asm volatile( "add %0, %1" : "+a" (i) : "a" (j));
+ return i;
+#else
+#error "No implementation for add8 available."
+#endif
+}
+
+
+/// subtract one byte from another, 8-bit result
+LIB8STATIC uint8_t sub8( uint8_t i, uint8_t j)
+{
+#if SUB8_C == 1
+ int t = i - j;
+ return t;
+#elif SUB8_AVRASM == 1
+ // Subtract j from i, period.
+ asm volatile( "sub %0, %1" : "+a" (i) : "a" (j));
+ return i;
+#else
+#error "No implementation for sub8 available."
+#endif
+}
+
+/// Calculate an integer average of two unsigned
+/// 8-bit integer values (uint8_t).
+/// Fractional results are rounded down, e.g. avg8(20,41) = 30
+LIB8STATIC uint8_t avg8( uint8_t i, uint8_t j)
+{
+#if AVG8_C == 1
+ return (i + j) >> 1;
+#elif AVG8_AVRASM == 1
+ asm volatile(
+ /* First, add j to i, 9th bit overflows into C flag */
+ "add %0, %1 \n\t"
+ /* Divide by two, moving C flag into high 8th bit */
+ "ror %0 \n\t"
+ : "+a" (i)
+ : "a" (j) );
+ return i;
+#else
+#error "No implementation for avg8 available."
+#endif
+}
+
+
+/// Calculate an integer average of two signed 7-bit
+/// integers (int8_t)
+/// If the first argument is even, result is rounded down.
+/// If the first argument is odd, result is result up.
+LIB8STATIC int8_t avg7( int8_t i, int8_t j)
+{
+#if AVG7_C == 1
+ return ((i + j) >> 1) + (i & 0x1);
+#elif AVG7_AVRASM == 1
+ asm volatile(
+ "asr %1 \n\t"
+ "asr %0 \n\t"
+ "adc %0, %1 \n\t"
+ : "+a" (i)
+ : "a" (j) );
+ return i;
+#else
+#error "No implementation for avg7 available."
+#endif
+}
+
+/// Calculate the remainder of one unsigned 8-bit
+/// value divided by anoter, aka A % M.
+/// Implemented by repeated subtraction, which is
+/// very compact, and very fast if A is 'probably'
+/// less than M. If A is a large multiple of M,
+/// the loop has to execute multiple times. However,
+/// even in that case, the loop is only two
+/// instructions long on AVR, i.e., quick.
+LIB8STATIC uint8_t mod8( uint8_t a, uint8_t m)
+{
+#if defined(__AVR__)
+ asm volatile (
+ "L_%=: sub %[a],%[m] \n\t"
+ " brcc L_%= \n\t"
+ " add %[a],%[m] \n\t"
+ : [a] "+r" (a)
+ : [m] "r" (m)
+ );
+#else
+ while( a >= m) a -= m;
+#endif
+ return a;
+}
+
+/// Add two numbers, and calculate the modulo
+/// of the sum and a third number, M.
+/// In other words, it returns (A+B) % M.
+/// It is designed as a compact mechanism for
+/// incrementing a 'mode' switch and wrapping
+/// around back to 'mode 0' when the switch
+/// goes past the end of the available range.
+/// e.g. if you have seven modes, this switches
+/// to the next one and wraps around if needed:
+/// mode = addmod8( mode, 1, 7);
+/// See 'mod8' for notes on performance.
+LIB8STATIC uint8_t addmod8( uint8_t a, uint8_t b, uint8_t m)
+{
+#if defined(__AVR__)
+ asm volatile (
+ " add %[a],%[b] \n\t"
+ "L_%=: sub %[a],%[m] \n\t"
+ " brcc L_%= \n\t"
+ " add %[a],%[m] \n\t"
+ : [a] "+r" (a)
+ : [b] "r" (b), [m] "r" (m)
+ );
+#else
+ a += b;
+ while( a >= m) a -= m;
+#endif
+ return a;
+}
+
+/// 8x8 bit multiplication, with 8 bit result
+LIB8STATIC uint8_t mul8( uint8_t i, uint8_t j)
+{
+#if MUL8_C == 1
+ return ((int)i * (int)(j) ) & 0xFF;
+#elif MUL8_AVRASM == 1
+ asm volatile(
+ /* Multiply 8-bit i * 8-bit j, giving 16-bit r1,r0 */
+ "mul %0, %1 \n\t"
+ /* Extract the LOW 8-bits (r0) */
+ "mov %0, r0 \n\t"
+ /* Restore r1 to "0"; it's expected to always be that */
+ "clr __zero_reg__ \n\t"
+ : "+a" (i)
+ : "a" (j)
+ : "r0", "r1");
+
+ return i;
+#else
+#error "No implementation for mul8 available."
+#endif
+}
+
+
+/// saturating 8x8 bit multiplication, with 8 bit result
+/// @returns the product of i * j, capping at 0xFF
+LIB8STATIC uint8_t qmul8( uint8_t i, uint8_t j)
+{
+#if QMUL8_C == 1
+ int p = ((int)i * (int)(j) );
+ if( p > 255) p = 255;
+ return p;
+#elif QMUL8_AVRASM == 1
+ asm volatile(
+ /* Multiply 8-bit i * 8-bit j, giving 16-bit r1,r0 */
+ " mul %0, %1 \n\t"
+ /* If high byte of result is zero, all is well. */
+ " tst r1 \n\t"
+ " breq Lnospill_%= \n\t"
+ /* If high byte of result > 0, saturate low byte to 0xFF */
+ " ldi %0,0xFF \n\t"
+ " rjmp Ldone_%= \n\t"
+ "Lnospill_%=: \n\t"
+ /* Extract the LOW 8-bits (r0) */
+ " mov %0, r0 \n\t"
+ "Ldone_%=: \n\t"
+ /* Restore r1 to "0"; it's expected to always be that */
+ " clr __zero_reg__ \n\t"
+ : "+a" (i)
+ : "a" (j)
+ : "r0", "r1");
+
+ return i;
+#else
+#error "No implementation for qmul8 available."
+#endif
+}
+
+
+/// take abs() of a signed 8-bit uint8_t
+LIB8STATIC int8_t abs8( int8_t i)
+{
+#if ABS8_C == 1
+ if( i < 0) i = -i;
+ return i;
+#elif ABS8_AVRASM == 1
+
+
+ asm volatile(
+ /* First, check the high bit, and prepare to skip if it's clear */
+ "sbrc %0, 7 \n"
+
+ /* Negate the value */
+ "neg %0 \n"
+
+ : "+r" (i) : "r" (i) );
+ return i;
+#else
+#error "No implementation for abs8 available."
+#endif
+}
+
+/// square root for 16-bit integers
+/// About three times faster and five times smaller
+/// than Arduino's general sqrt on AVR.
+LIB8STATIC uint8_t sqrt16(uint16_t x)
+{
+ if( x <= 1) {
+ return x;
+ }
+
+ uint8_t low = 1; // lower bound
+ uint8_t hi, mid;
+
+ if( x > 7904) {
+ hi = 255;
+ } else {
+ hi = (x >> 5) + 8; // initial estimate for upper bound
+ }
+
+ do {
+ mid = (low + hi) >> 1;
+ if ((uint16_t)(mid * mid) > x) {
+ hi = mid - 1;
+ } else {
+ if( mid == 255) {
+ return 255;
+ }
+ low = mid + 1;
+ }
+ } while (hi >= low);
+
+ return low - 1;
+}
+
+///@}
+#endif
diff --git a/lib8tion/random8.h b/lib8tion/random8.h
new file mode 100644
index 00000000..95ba6a5c
--- /dev/null
+++ b/lib8tion/random8.h
@@ -0,0 +1,92 @@
+#ifndef __INC_LIB8TION_RANDOM_H
+#define __INC_LIB8TION_RANDOM_H
+///@ingroup lib8tion
+
+///@defgroup Random Fast random number generators
+/// A 16-bit PNRG good enough for LED animations
+///@{
+
+// X(n+1) = (2053 * X(n)) + 13849)
+#define FASTLED_RAND16_2053 ((uint16_t)(2053))
+#define FASTLED_RAND16_13849 ((uint16_t)(13849))
+
+/// random number seed
+extern uint16_t rand16seed;// = RAND16_SEED;
+
+/// Generate an 8-bit random number
+LIB8STATIC uint8_t random8()
+{
+ rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
+ // return the sum of the high and low bytes, for better
+ // mixing and non-sequential correlation
+ return (uint8_t)(((uint8_t)(rand16seed & 0xFF)) +
+ ((uint8_t)(rand16seed >> 8)));
+}
+
+/// Generate a 16 bit random number
+LIB8STATIC uint16_t random16()
+{
+ rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
+ return rand16seed;
+}
+
+/// Generate an 8-bit random number between 0 and lim
+/// @param lim the upper bound for the result
+LIB8STATIC uint8_t random8(uint8_t lim)
+{
+ uint8_t r = random8();
+ r = scale8( r, lim);
+ return r;
+}
+
+/// Generate an 8-bit random number in the given range
+/// @param min the lower bound for the random number
+/// @param lim the upper bound for the random number
+LIB8STATIC uint8_t random8(uint8_t min, uint8_t lim)
+{
+ uint8_t delta = lim - min;
+ uint8_t r = random8(delta) + min;
+ return r;
+}
+
+/// Generate an 16-bit random number between 0 and lim
+/// @param lim the upper bound for the result
+LIB8STATIC uint16_t random16( uint16_t lim)
+{
+ uint16_t r = random16();
+ uint32_t p = (uint32_t)lim * (uint32_t)r;
+ r = p >> 16;
+ return r;
+}
+
+/// Generate an 16-bit random number in the given range
+/// @param min the lower bound for the random number
+/// @param lim the upper bound for the random number
+LIB8STATIC uint16_t random16( uint16_t min, uint16_t lim)
+{
+ uint16_t delta = lim - min;
+ uint16_t r = random16( delta) + min;
+ return r;
+}
+
+/// Set the 16-bit seed used for the random number generator
+LIB8STATIC void random16_set_seed( uint16_t seed)
+{
+ rand16seed = seed;
+}
+
+/// Get the current seed value for the random number generator
+LIB8STATIC uint16_t random16_get_seed()
+{
+ return rand16seed;
+}
+
+/// Add entropy into the random number generator
+LIB8STATIC void random16_add_entropy( uint16_t entropy)
+{
+ rand16seed += entropy;
+}
+
+///@}
+
+#endif
diff --git a/lib8tion/scale8.h b/lib8tion/scale8.h
new file mode 100644
index 00000000..e9c95759
--- /dev/null
+++ b/lib8tion/scale8.h
@@ -0,0 +1,505 @@
+#ifndef __INC_LIB8TION_SCALE_H
+#define __INC_LIB8TION_SCALE_H
+
+///@ingroup lib8tion
+
+///@defgroup Scaling Scaling functions
+/// for scaling 8 and 16 bit values, as well as dimming and brightening them
+///@{
+
+/// scale one byte by a second one, which is treated as
+/// the numerator of a fraction whose denominator is 256
+/// In other words, it computes i * (scale / 256)
+/// 4 clocks AVR with MUL, 2 clocks ARM
+LIB8STATIC uint8_t scale8( uint8_t i, fract8 scale)
+{
+#if SCALE8_C == 1
+ return ((uint16_t)i * (uint16_t)(scale) ) >> 8;
+#elif SCALE8_AVRASM == 1
+#if defined(LIB8_ATTINY)
+ uint8_t work=0;
+ uint8_t cnt=0x80;
+ asm volatile(
+ "LOOP_%=: \n\t"
+ /*" sbrc %[scale], 0 \n\t"
+ " add %[work], %[i] \n\t"
+ " ror %[work] \n\t"
+ " lsr %[scale] \n\t"
+ " clc \n\t"*/
+ " sbrc %[scale], 0 \n\t"
+ " add %[work], %[i] \n\t"
+ " ror %[work] \n\t"
+ " lsr %[scale] \n\t"
+ " lsr %[cnt] \n\t"
+ "brcc LOOP_%="
+ : [work] "+r" (work), [cnt] "+r" (cnt)
+ : [scale] "r" (scale), [i] "r" (i)
+ :
+ );
+ return work;
+#else
+ asm volatile(
+ /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
+ "mul %0, %1 \n\t"
+ /* Move the high 8-bits of the product (r1) back to i */
+ "mov %0, r1 \n\t"
+ /* Restore r1 to "0"; it's expected to always be that */
+ "clr __zero_reg__ \n\t"
+
+ : "+a" (i) /* writes to i */
+ : "a" (scale) /* uses scale */
+ : "r0", "r1" /* clobbers r0, r1 */ );
+
+ /* Return the result */
+ return i;
+#endif
+#else
+#error "No implementation for scale8 available."
+#endif
+}
+
+
+/// The "video" version of scale8 guarantees that the output will
+/// be only be zero if one or both of the inputs are zero. If both
+/// inputs are non-zero, the output is guaranteed to be non-zero.
+/// This makes for better 'video'/LED dimming, at the cost of
+/// several additional cycles.
+LIB8STATIC uint8_t scale8_video( uint8_t i, fract8 scale)
+{
+#if SCALE8_C == 1 || defined(LIB8_ATTINY)
+ uint8_t j = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
+ // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ // uint8_t j = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
+ return j;
+#elif SCALE8_AVRASM == 1
+ uint8_t j=0;
+ asm volatile(
+ " tst %[i]\n\t"
+ " breq L_%=\n\t"
+ " mul %[i], %[scale]\n\t"
+ " mov %[j], r1\n\t"
+ " clr __zero_reg__\n\t"
+ " cpse %[scale], r1\n\t"
+ " subi %[j], 0xFF\n\t"
+ "L_%=: \n\t"
+ : [j] "+a" (j)
+ : [i] "a" (i), [scale] "a" (scale)
+ : "r0", "r1");
+
+ return j;
+ // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ // asm volatile(
+ // " tst %0 \n"
+ // " breq L_%= \n"
+ // " mul %0, %1 \n"
+ // " mov %0, r1 \n"
+ // " add %0, %2 \n"
+ // " clr __zero_reg__ \n"
+ // "L_%=: \n"
+
+ // : "+a" (i)
+ // : "a" (scale), "a" (nonzeroscale)
+ // : "r0", "r1");
+
+ // // Return the result
+ // return i;
+#else
+#error "No implementation for scale8_video available."
+#endif
+}
+
+
+/// This version of scale8 does not clean up the R1 register on AVR
+/// If you are doing several 'scale8's in a row, use this, and
+/// then explicitly call cleanup_R1.
+LIB8STATIC uint8_t scale8_LEAVING_R1_DIRTY( uint8_t i, fract8 scale)
+{
+#if SCALE8_C == 1
+ return ((int)i * (int)(scale) ) >> 8;
+#elif SCALE8_AVRASM == 1
+ asm volatile(
+ /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
+ "mul %0, %1 \n\t"
+ /* Move the high 8-bits of the product (r1) back to i */
+ "mov %0, r1 \n\t"
+ /* R1 IS LEFT DIRTY HERE; YOU MUST ZERO IT OUT YOURSELF */
+ /* "clr __zero_reg__ \n\t" */
+
+ : "+a" (i) /* writes to i */
+ : "a" (scale) /* uses scale */
+ : "r0", "r1" /* clobbers r0, r1 */ );
+
+ // Return the result
+ return i;
+#else
+#error "No implementation for scale8_LEAVING_R1_DIRTY available."
+#endif
+}
+
+/// In place modifying version of scale8, also this version of nscale8 does not
+/// clean up the R1 register on AVR
+/// If you are doing several 'scale8's in a row, use this, and
+/// then explicitly call cleanup_R1.
+
+LIB8STATIC void nscale8_LEAVING_R1_DIRTY( uint8_t& i, fract8 scale)
+{
+#if SCALE8_C == 1
+ i = ((int)i * (int)(scale) ) >> 8;
+#elif SCALE8_AVRASM == 1
+ asm volatile(
+ /* Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0 */
+ "mul %0, %1 \n\t"
+ /* Move the high 8-bits of the product (r1) back to i */
+ "mov %0, r1 \n\t"
+ /* R1 IS LEFT DIRTY HERE; YOU MUST ZERO IT OUT YOURSELF */
+ /* "clr __zero_reg__ \n\t" */
+
+ : "+a" (i) /* writes to i */
+ : "a" (scale) /* uses scale */
+ : "r0", "r1" /* clobbers r0, r1 */ );
+#else
+#error "No implementation for nscale8_LEAVING_R1_DIRTY available."
+#endif
+}
+
+
+/// This version of scale8_video does not clean up the R1 register on AVR
+/// If you are doing several 'scale8_video's in a row, use this, and
+/// then explicitly call cleanup_R1.
+LIB8STATIC uint8_t scale8_video_LEAVING_R1_DIRTY( uint8_t i, fract8 scale)
+{
+#if SCALE8_C == 1 || defined(LIB8_ATTINY)
+ uint8_t j = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
+ // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ // uint8_t j = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
+ return j;
+#elif SCALE8_AVRASM == 1
+ uint8_t j=0;
+ asm volatile(
+ " tst %[i]\n\t"
+ " breq L_%=\n\t"
+ " mul %[i], %[scale]\n\t"
+ " mov %[j], r1\n\t"
+ " breq L_%=\n\t"
+ " subi %[j], 0xFF\n\t"
+ "L_%=: \n\t"
+ : [j] "+a" (j)
+ : [i] "a" (i), [scale] "a" (scale)
+ : "r0", "r1");
+
+ return j;
+ // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ // asm volatile(
+ // " tst %0 \n"
+ // " breq L_%= \n"
+ // " mul %0, %1 \n"
+ // " mov %0, r1 \n"
+ // " add %0, %2 \n"
+ // " clr __zero_reg__ \n"
+ // "L_%=: \n"
+
+ // : "+a" (i)
+ // : "a" (scale), "a" (nonzeroscale)
+ // : "r0", "r1");
+
+ // // Return the result
+ // return i;
+#else
+#error "No implementation for scale8_video_LEAVING_R1_DIRTY available."
+#endif
+}
+
+/// In place modifying version of scale8_video, also this version of nscale8_video
+/// does not clean up the R1 register on AVR
+/// If you are doing several 'scale8_video's in a row, use this, and
+/// then explicitly call cleanup_R1.
+LIB8STATIC void nscale8_video_LEAVING_R1_DIRTY( uint8_t & i, fract8 scale)
+{
+#if SCALE8_C == 1 || defined(LIB8_ATTINY)
+ i = (((int)i * (int)scale) >> 8) + ((i&&scale)?1:0);
+#elif SCALE8_AVRASM == 1
+ asm volatile(
+ " tst %[i]\n\t"
+ " breq L_%=\n\t"
+ " mul %[i], %[scale]\n\t"
+ " mov %[i], r1\n\t"
+ " breq L_%=\n\t"
+ " subi %[i], 0xFF\n\t"
+ "L_%=: \n\t"
+ : [i] "+a" (i)
+ : [scale] "a" (scale)
+ : "r0", "r1");
+#else
+#error "No implementation for scale8_video_LEAVING_R1_DIRTY available."
+#endif
+}
+
+/// Clean up the r1 register after a series of *LEAVING_R1_DIRTY calls
+LIB8STATIC void cleanup_R1()
+{
+#if CLEANUP_R1_AVRASM == 1
+ // Restore r1 to "0"; it's expected to always be that
+ asm volatile( "clr __zero_reg__ \n\t" : : : "r1" );
+#endif
+}
+
+
+/// scale three one byte values by a fourth one, which is treated as
+/// the numerator of a fraction whose demominator is 256
+/// In other words, it computes r,g,b * (scale / 256)
+///
+/// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
+
+LIB8STATIC void nscale8x3( uint8_t& r, uint8_t& g, uint8_t& b, fract8 scale)
+{
+#if SCALE8_C == 1
+ r = ((int)r * (int)(scale) ) >> 8;
+ g = ((int)g * (int)(scale) ) >> 8;
+ b = ((int)b * (int)(scale) ) >> 8;
+#elif SCALE8_AVRASM == 1
+ r = scale8_LEAVING_R1_DIRTY(r, scale);
+ g = scale8_LEAVING_R1_DIRTY(g, scale);
+ b = scale8_LEAVING_R1_DIRTY(b, scale);
+ cleanup_R1();
+#else
+#error "No implementation for nscale8x3 available."
+#endif
+}
+
+/// scale three one byte values by a fourth one, which is treated as
+/// the numerator of a fraction whose demominator is 256
+/// In other words, it computes r,g,b * (scale / 256), ensuring
+/// that non-zero values passed in remain non zero, no matter how low the scale
+/// argument.
+///
+/// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
+LIB8STATIC void nscale8x3_video( uint8_t& r, uint8_t& g, uint8_t& b, fract8 scale)
+{
+#if SCALE8_C == 1
+ uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ r = (r == 0) ? 0 : (((int)r * (int)(scale) ) >> 8) + nonzeroscale;
+ g = (g == 0) ? 0 : (((int)g * (int)(scale) ) >> 8) + nonzeroscale;
+ b = (b == 0) ? 0 : (((int)b * (int)(scale) ) >> 8) + nonzeroscale;
+#elif SCALE8_AVRASM == 1
+ nscale8_video_LEAVING_R1_DIRTY( r, scale);
+ nscale8_video_LEAVING_R1_DIRTY( g, scale);
+ nscale8_video_LEAVING_R1_DIRTY( b, scale);
+ cleanup_R1();
+#else
+#error "No implementation for nscale8x3 available."
+#endif
+}
+
+/// scale two one byte values by a third one, which is treated as
+/// the numerator of a fraction whose demominator is 256
+/// In other words, it computes i,j * (scale / 256)
+///
+/// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
+
+LIB8STATIC void nscale8x2( uint8_t& i, uint8_t& j, fract8 scale)
+{
+#if SCALE8_C == 1
+ i = ((int)i * (int)(scale) ) >> 8;
+ j = ((int)j * (int)(scale) ) >> 8;
+#elif SCALE8_AVRASM == 1
+ i = scale8_LEAVING_R1_DIRTY(i, scale);
+ j = scale8_LEAVING_R1_DIRTY(j, scale);
+ cleanup_R1();
+#else
+#error "No implementation for nscale8x2 available."
+#endif
+}
+
+/// scale two one byte values by a third one, which is treated as
+/// the numerator of a fraction whose demominator is 256
+/// In other words, it computes i,j * (scale / 256), ensuring
+/// that non-zero values passed in remain non zero, no matter how low the scale
+/// argument.
+///
+/// THIS FUNCTION ALWAYS MODIFIES ITS ARGUMENTS IN PLACE
+
+
+LIB8STATIC void nscale8x2_video( uint8_t& i, uint8_t& j, fract8 scale)
+{
+#if SCALE8_C == 1
+ uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
+ i = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;
+ j = (j == 0) ? 0 : (((int)j * (int)(scale) ) >> 8) + nonzeroscale;
+#elif SCALE8_AVRASM == 1
+ nscale8_video_LEAVING_R1_DIRTY( i, scale);
+ nscale8_video_LEAVING_R1_DIRTY( j, scale);
+ cleanup_R1();
+#else
+#error "No implementation for nscale8x2 available."
+#endif
+}
+
+
+/// scale a 16-bit unsigned value by an 8-bit value,
+/// considered as numerator of a fraction whose denominator
+/// is 256. In other words, it computes i * (scale / 256)
+
+LIB8STATIC uint16_t scale16by8( uint16_t i, fract8 scale )
+{
+#if SCALE16BY8_C == 1
+ uint16_t result;
+ result = (i * scale) / 256;
+ return result;
+#elif SCALE16BY8_AVRASM == 1
+ uint16_t result = 0;
+ asm volatile(
+ // result.A = HighByte(i.A x j )
+ " mul %A[i], %[scale] \n\t"
+ " mov %A[result], r1 \n\t"
+ //" clr %B[result] \n\t"
+
+ // result.A-B += i.B x j
+ " mul %B[i], %[scale] \n\t"
+ " add %A[result], r0 \n\t"
+ " adc %B[result], r1 \n\t"
+
+ // cleanup r1
+ " clr __zero_reg__ \n\t"
+
+ : [result] "+r" (result)
+ : [i] "r" (i), [scale] "r" (scale)
+ : "r0", "r1"
+ );
+ return result;
+#else
+ #error "No implementation for scale16by8 available."
+#endif
+}
+
+/// scale a 16-bit unsigned value by a 16-bit value,
+/// considered as numerator of a fraction whose denominator
+/// is 65536. In other words, it computes i * (scale / 65536)
+
+LIB8STATIC uint16_t scale16( uint16_t i, fract16 scale )
+{
+ #if SCALE16_C == 1
+ uint16_t result;
+ result = ((uint32_t)(i) * (uint32_t)(scale)) / 65536;
+ return result;
+#elif SCALE16_AVRASM == 1
+ uint32_t result = 0;
+ const uint8_t zero = 0;
+ asm volatile(
+ // result.A-B = i.A x scale.A
+ " mul %A[i], %A[scale] \n\t"
+ // save results...
+ // basic idea:
+ //" mov %A[result], r0 \n\t"
+ //" mov %B[result], r1 \n\t"
+ // which can be written as...
+ " movw %A[result], r0 \n\t"
+ // We actually need to do anything with r0,
+ // as result.A is never used again here, so we
+ // could just move the high byte, but movw is
+ // one clock cycle, just like mov, so might as
+ // well, in case we want to use this code for
+ // a generic 16x16 multiply somewhere.
+
+ // result.C-D = i.B x scale.B
+ " mul %B[i], %B[scale] \n\t"
+ //" mov %C[result], r0 \n\t"
+ //" mov %D[result], r1 \n\t"
+ " movw %C[result], r0 \n\t"
+
+ // result.B-D += i.B x scale.A
+ " mul %B[i], %A[scale] \n\t"
+
+ " add %B[result], r0 \n\t"
+ " adc %C[result], r1 \n\t"
+ " adc %D[result], %[zero] \n\t"
+
+ // result.B-D += i.A x scale.B
+ " mul %A[i], %B[scale] \n\t"
+
+ " add %B[result], r0 \n\t"
+ " adc %C[result], r1 \n\t"
+ " adc %D[result], %[zero] \n\t"
+
+ // cleanup r1
+ " clr r1 \n\t"
+
+ : [result] "+r" (result)
+ : [i] "r" (i),
+ [scale] "r" (scale),
+ [zero] "r" (zero)
+ : "r0", "r1"
+ );
+ result = result >> 16;
+ return result;
+#else
+ #error "No implementation for scale16 available."
+#endif
+}
+///@}
+
+///@defgroup Dimming Dimming and brightening functions
+///
+/// Dimming and brightening functions
+///
+/// The eye does not respond in a linear way to light.
+/// High speed PWM'd LEDs at 50% duty cycle appear far
+/// brighter then the 'half as bright' you might expect.
+///
+/// If you want your midpoint brightness leve (128) to
+/// appear half as bright as 'full' brightness (255), you
+/// have to apply a 'dimming function'.
+///@{
+
+/// Adjust a scaling value for dimming
+LIB8STATIC uint8_t dim8_raw( uint8_t x)
+{
+ return scale8( x, x);
+}
+
+/// Adjust a scaling value for dimming for video (value will never go below 1)
+LIB8STATIC uint8_t dim8_video( uint8_t x)
+{
+ return scale8_video( x, x);
+}
+
+/// Linear version of the dimming function that halves for values < 128
+LIB8STATIC uint8_t dim8_lin( uint8_t x )
+{
+ if( x & 0x80 ) {
+ x = scale8( x, x);
+ } else {
+ x += 1;
+ x /= 2;
+ }
+ return x;
+}
+
+/// inverse of the dimming function, brighten a value
+LIB8STATIC uint8_t brighten8_raw( uint8_t x)
+{
+ uint8_t ix = 255 - x;
+ return 255 - scale8( ix, ix);
+}
+
+/// inverse of the dimming function, brighten a value
+LIB8STATIC uint8_t brighten8_video( uint8_t x)
+{
+ uint8_t ix = 255 - x;
+ return 255 - scale8_video( ix, ix);
+}
+
+/// inverse of the dimming function, brighten a value
+LIB8STATIC uint8_t brighten8_lin( uint8_t x )
+{
+ uint8_t ix = 255 - x;
+ if( ix & 0x80 ) {
+ ix = scale8( ix, ix);
+ } else {
+ ix += 1;
+ ix /= 2;
+ }
+ return 255 - ix;
+}
+
+///@}
+#endif
diff --git a/lib8tion/trig8.h b/lib8tion/trig8.h
new file mode 100644
index 00000000..f9e483ae
--- /dev/null
+++ b/lib8tion/trig8.h
@@ -0,0 +1,267 @@
+#ifndef __INC_LIB8TION_TRIG_H
+#define __INC_LIB8TION_TRIG_H
+
+///@ingroup lib8tion
+
+///@defgroup Trig Fast trig functions
+///@{
+
+// sin16 & cos16:
+// Fast 16-bit approximations of sin(x) & cos(x).
+// Input angle is an unsigned int from 0-65535.
+// Output is signed int from -32767 to 32767.
+//
+// This approximation never varies more than 0.69%
+// from the floating point value you'd get by doing
+// float s = sin( x ) * 32767.0;
+//
+// Don't use this approximation for calculating the
+// trajectory of a rocket to Mars, but it's great
+// for art projects and LED displays.
+//
+// On Arduino/AVR, this approximation is more than
+// 10X faster than floating point sin(x) and cos(x)
+
+#if defined(__AVR__)
+#define sin16 sin16_avr
+#else
+#define sin16 sin16_C
+#endif
+
+/// Fast 16-bit approximation of sin(x). This approximation never varies more than
+/// 0.69% from the floating point value you'd get by doing
+///
+/// float s = sin(x) * 32767.0;
+///
+/// @param theta input angle from 0-65535
+/// @returns sin of theta, value between -32767 to 32767.
+LIB8STATIC int16_t sin16_avr( uint16_t theta )
+{
+ static const uint8_t data[] =
+ { 0, 0, 49, 0, 6393%256, 6393/256, 48, 0,
+ 12539%256, 12539/256, 44, 0, 18204%256, 18204/256, 38, 0,
+ 23170%256, 23170/256, 31, 0, 27245%256, 27245/256, 23, 0,
+ 30273%256, 30273/256, 14, 0, 32137%256, 32137/256, 4 /*,0*/ };
+
+ uint16_t offset = (theta & 0x3FFF);
+
+ // AVR doesn't have a multi-bit shift instruction,
+ // so if we say "offset >>= 3", gcc makes a tiny loop.
+ // Inserting empty volatile statements between each
+ // bit shift forces gcc to unroll the loop.
+ offset >>= 1; // 0..8191
+ asm volatile("");
+ offset >>= 1; // 0..4095
+ asm volatile("");
+ offset >>= 1; // 0..2047
+
+ if( theta & 0x4000 ) offset = 2047 - offset;
+
+ uint8_t sectionX4;
+ sectionX4 = offset / 256;
+ sectionX4 *= 4;
+
+ uint8_t m;
+
+ union {
+ uint16_t b;
+ struct {
+ uint8_t blo;
+ uint8_t bhi;
+ };
+ } u;
+
+ //in effect u.b = blo + (256 * bhi);
+ u.blo = data[ sectionX4 ];
+ u.bhi = data[ sectionX4 + 1];
+ m = data[ sectionX4 + 2];
+
+ uint8_t secoffset8 = (uint8_t)(offset) / 2;
+
+ uint16_t mx = m * secoffset8;
+
+ int16_t y = mx + u.b;
+ if( theta & 0x8000 ) y = -y;
+
+ return y;
+}
+
+/// Fast 16-bit approximation of sin(x). This approximation never varies more than
+/// 0.69% from the floating point value you'd get by doing
+///
+/// float s = sin(x) * 32767.0;
+///
+/// @param theta input angle from 0-65535
+/// @returns sin of theta, value between -32767 to 32767.
+LIB8STATIC int16_t sin16_C( uint16_t theta )
+{
+ static const uint16_t base[] =
+ { 0, 6393, 12539, 18204, 23170, 27245, 30273, 32137 };
+ static const uint8_t slope[] =
+ { 49, 48, 44, 38, 31, 23, 14, 4 };
+
+ uint16_t offset = (theta & 0x3FFF) >> 3; // 0..2047
+ if( theta & 0x4000 ) offset = 2047 - offset;
+
+ uint8_t section = offset / 256; // 0..7
+ uint16_t b = base[section];
+ uint8_t m = slope[section];
+
+ uint8_t secoffset8 = (uint8_t)(offset) / 2;
+
+ uint16_t mx = m * secoffset8;
+ int16_t y = mx + b;
+
+ if( theta & 0x8000 ) y = -y;
+
+ return y;
+}
+
+
+/// Fast 16-bit approximation of cos(x). This approximation never varies more than
+/// 0.69% from the floating point value you'd get by doing
+///
+/// float s = cos(x) * 32767.0;
+///
+/// @param theta input angle from 0-65535
+/// @returns sin of theta, value between -32767 to 32767.
+LIB8STATIC int16_t cos16( uint16_t theta)
+{
+ return sin16( theta + 16384);
+}
+
+///////////////////////////////////////////////////////////////////////
+
+// sin8 & cos8
+// Fast 8-bit approximations of sin(x) & cos(x).
+// Input angle is an unsigned int from 0-255.
+// Output is an unsigned int from 0 to 255.
+//
+// This approximation can vary to to 2%
+// from the floating point value you'd get by doing
+// float s = (sin( x ) * 128.0) + 128;
+//
+// Don't use this approximation for calculating the
+// "real" trigonometric calculations, but it's great
+// for art projects and LED displays.
+//
+// On Arduino/AVR, this approximation is more than
+// 20X faster than floating point sin(x) and cos(x)
+
+#if defined(__AVR__) && !defined(LIB8_ATTINY)
+#define sin8 sin8_avr
+#else
+#define sin8 sin8_C
+#endif
+
+
+const uint8_t b_m16_interleave[] = { 0, 49, 49, 41, 90, 27, 117, 10 };
+
+/// Fast 8-bit approximation of sin(x). This approximation never varies more than
+/// 2% from the floating point value you'd get by doing
+///
+/// float s = (sin(x) * 128.0) + 128;
+///
+/// @param theta input angle from 0-255
+/// @returns sin of theta, value between 0 and 255
+LIB8STATIC uint8_t sin8_avr( uint8_t theta)
+{
+ uint8_t offset = theta;
+
+ asm volatile(
+ "sbrc %[theta],6 \n\t"
+ "com %[offset] \n\t"
+ : [theta] "+r" (theta), [offset] "+r" (offset)
+ );
+
+ offset &= 0x3F; // 0..63
+
+ uint8_t secoffset = offset & 0x0F; // 0..15
+ if( theta & 0x40) secoffset++;
+
+ uint8_t m16; uint8_t b;
+
+ uint8_t section = offset >> 4; // 0..3
+ uint8_t s2 = section * 2;
+
+ const uint8_t* p = b_m16_interleave;
+ p += s2;
+ b = *p;
+ p++;
+ m16 = *p;
+
+ uint8_t mx;
+ uint8_t xr1;
+ asm volatile(
+ "mul %[m16],%[secoffset] \n\t"
+ "mov %[mx],r0 \n\t"
+ "mov %[xr1],r1 \n\t"
+ "eor r1, r1 \n\t"
+ "swap %[mx] \n\t"
+ "andi %[mx],0x0F \n\t"
+ "swap %[xr1] \n\t"
+ "andi %[xr1], 0xF0 \n\t"
+ "or %[mx], %[xr1] \n\t"
+ : [mx] "=r" (mx), [xr1] "=r" (xr1)
+ : [m16] "r" (m16), [secoffset] "r" (secoffset)
+ );
+
+ int8_t y = mx + b;
+ if( theta & 0x80 ) y = -y;
+
+ y += 128;
+
+ return y;
+}
+
+
+/// Fast 8-bit approximation of sin(x). This approximation never varies more than
+/// 2% from the floating point value you'd get by doing
+///
+/// float s = (sin(x) * 128.0) + 128;
+///
+/// @param theta input angle from 0-255
+/// @returns sin of theta, value between 0 and 255
+LIB8STATIC uint8_t sin8_C( uint8_t theta)
+{
+ uint8_t offset = theta;
+ if( theta & 0x40 ) {
+ offset = (uint8_t)255 - offset;
+ }
+ offset &= 0x3F; // 0..63
+
+ uint8_t secoffset = offset & 0x0F; // 0..15
+ if( theta & 0x40) secoffset++;
+
+ uint8_t section = offset >> 4; // 0..3
+ uint8_t s2 = section * 2;
+ const uint8_t* p = b_m16_interleave;
+ p += s2;
+ uint8_t b = *p;
+ p++;
+ uint8_t m16 = *p;
+
+ uint8_t mx = (m16 * secoffset) >> 4;
+
+ int8_t y = mx + b;
+ if( theta & 0x80 ) y = -y;
+
+ y += 128;
+
+ return y;
+}
+
+/// Fast 8-bit approximation of cos(x). This approximation never varies more than
+/// 2% from the floating point value you'd get by doing
+///
+/// float s = (cos(x) * 128.0) + 128;
+///
+/// @param theta input angle from 0-255
+/// @returns sin of theta, value between 0 and 255
+LIB8STATIC uint8_t cos8( uint8_t theta)
+{
+ return sin8( theta + 64);
+}
+
+///@}
+#endif