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qmk_firmware/lib/lib8tion/scale8.h

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RGB Matrix Overhaul (#5372) * RGB Matrix overhaul Breakout of animations to separate files Integration of optimized int based math lib Overhaul of rgb_matrix.c and animations for performance * Updating effect function api for future extensions * Combined the keypresses || keyreleases define checks into a single define so I stop forgetting it where necessary * Moving define RGB_MATRIX_KEYREACTIVE_ENABLED earlier in the include chain
6 years ago
#ifndef __INC_LIB8TION_SCALE_H
#define __INC_LIB8TION_SCALE_H
///@ingroup lib8tion
///@defgroup Scaling Scaling functions
/// Fast, efficient 8-bit scaling functions specifically
/// designed for high-performance LED programming.
///
/// Because of the AVR(Arduino) and ARM assembly language
/// implementations provided, using these functions often
/// results in smaller and faster code than the equivalent
/// program using plain "C" arithmetic and logic.
///@{
/// 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_ALWAYS_INLINE uint8_t scale8( uint8_t i, fract8 scale)
{
#if SCALE8_C == 1
#if (FASTLED_SCALE8_FIXED == 1)
return (((uint16_t)i) * (1+(uint16_t)(scale))) >> 8;
#else
return ((uint16_t)i * (uint16_t)(scale) ) >> 8;
#endif
#elif SCALE8_AVRASM == 1
#if defined(LIB8_ATTINY)
#if (FASTLED_SCALE8_FIXED == 1)
uint8_t work=i;
#else
uint8_t work=0;
#endif
uint8_t cnt=0x80;
asm volatile(
#if (FASTLED_SCALE8_FIXED == 1)
" inc %[scale] \n\t"
" breq DONE_%= \n\t"
" clr %[work] \n\t"
#endif
"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_%= \n\t"
"DONE_%=: \n\t"
: [work] "+r" (work), [cnt] "+r" (cnt)
: [scale] "r" (scale), [i] "r" (i)
:
);
return work;
#else
asm volatile(
#if (FASTLED_SCALE8_FIXED==1)
// Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0
"mul %0, %1 \n\t"
// Add i to r0, possibly setting the carry flag
"add r0, %0 \n\t"
// load the immediate 0 into i (note, this does _not_ touch any flags)
"ldi %0, 0x00 \n\t"
// walk and chew gum at the same time
"adc %0, r1 \n\t"
#else
/* 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 */
#endif
"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_ALWAYS_INLINE 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_ALWAYS_INLINE uint8_t scale8_LEAVING_R1_DIRTY( uint8_t i, fract8 scale)
{
#if SCALE8_C == 1
#if (FASTLED_SCALE8_FIXED == 1)
return (((uint16_t)i) * ((uint16_t)(scale)+1)) >> 8;
#else
return ((int)i * (int)(scale) ) >> 8;
#endif
#elif SCALE8_AVRASM == 1
asm volatile(
#if (FASTLED_SCALE8_FIXED==1)
// Multiply 8-bit i * 8-bit scale, giving 16-bit r1,r0
"mul %0, %1 \n\t"
// Add i to r0, possibly setting the carry flag
"add r0, %0 \n\t"
// load the immediate 0 into i (note, this does _not_ touch any flags)
"ldi %0, 0x00 \n\t"
// walk and chew gum at the same time
"adc %0, r1 \n\t"
#else
/* 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"
#endif
/* 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 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_ALWAYS_INLINE 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
}
/// Clean up the r1 register after a series of *LEAVING_R1_DIRTY calls
LIB8STATIC_ALWAYS_INLINE void cleanup_R1(void)
{
#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 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_ALWAYS_INLINE uint16_t scale16by8( uint16_t i, fract8 scale )
{
#if SCALE16BY8_C == 1
uint16_t result;
#if FASTLED_SCALE8_FIXED == 1
result = (i * (1+((uint16_t)scale))) >> 8;
#else
result = (i * scale) / 256;
#endif
return result;
#elif SCALE16BY8_AVRASM == 1
#if FASTLED_SCALE8_FIXED == 1
uint16_t result = 0;
asm volatile(
// result.A = HighByte( (i.A x scale) + i.A )
" mul %A[i], %[scale] \n\t"
" add r0, %A[i] \n\t"
// " adc r1, [zero] \n\t"
// " mov %A[result], r1 \n\t"
" adc %A[result], r1 \n\t"
// result.A-B += i.B x scale
" 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.A-B += i.B
" add %A[result], %B[i] \n\t"
" adc %B[result], __zero_reg__ \n\t"
: [result] "+r" (result)
: [i] "r" (i), [scale] "r" (scale)
: "r0", "r1"
);
return result;
#else
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;
#endif
#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;
#if FASTLED_SCALE8_FIXED == 1
result = ((uint32_t)(i) * (1+(uint32_t)(scale))) / 65536;
#else
result = ((uint32_t)(i) * (uint32_t)(scale)) / 65536;
#endif
return result;
#elif SCALE16_AVRASM == 1
#if FASTLED_SCALE8_FIXED == 1
// implemented sort of like
// result = ((i * scale) + i ) / 65536
//
// why not like this, you may ask?
// result = (i * (scale+1)) / 65536
// the answer is that if scale is 65535, then scale+1
// will be zero, which is not what we want.
uint32_t result;
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"
// Because we're going to add i.A-B to
// result.A-D, we DO need to keep both
// the r0 and r1 portions of the product
// UNlike in the 'unfixed scale8' version.
// So the movw here is needed.
: [result] "=r" (result)
: [i] "r" (i),
[scale] "r" (scale)
: "r0", "r1"
);
asm volatile(
// 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] "+r" (result)
: [i] "r" (i),
[scale] "r" (scale)
: "r0", "r1"
);
const uint8_t zero = 0;
asm volatile(
// 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"
);
asm volatile(
// result.A-D += i.A-B
" add %A[result], %A[i] \n\t"
" adc %B[result], %B[i] \n\t"
" adc %C[result], %[zero] \n\t"
" adc %D[result], %[zero] \n\t"
: [result] "+r" (result)
: [i] "r" (i),
[zero] "r" (zero)
);
result = result >> 16;
return result;
#else
uint32_t result;
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 don't 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] "=r" (result)
: [i] "r" (i),
[scale] "r" (scale)
: "r0", "r1"
);
asm volatile(
// 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] "+r" (result)
: [i] "r" (i),
[scale] "r" (scale)
: "r0", "r1"
);
const uint8_t zero = 0;
asm volatile(
// 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;
#endif
#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