still unused code for ATTiny version of scale8, to get rid of calls to mul. Add ability to modify FastLED.h to disable color correction and/or dithering (with program space savings)

4 files changed, 37 insertions, 3 deletions

diff --git a/FastLED.h b/FastLED.h
index 1fe8acdb..6f335a1e 100644
--- a/FastLED.h
+++ b/FastLED.h
@@ -1,6 +1,9 @@
 #ifndef __INC_FASTSPI_LED2_H
 #define __INC_FASTSPI_LED2_H
 
+// #define NO_CORRECTION 1
+// #define NO_DITHERING 1
+
 #include "controller.h"
 #include "fastpin.h"
 #include "fastspi.h"
diff --git a/clockless_trinket.h b/clockless_trinket.h
index 83cd2e84..7d99cbd9 100644
--- a/clockless_trinket.h
+++ b/clockless_trinket.h
@@ -95,8 +95,10 @@ public:
 		showRGBInternal(pixels);
 
 		// Adjust the timer
+#if !defined(NO_CORRECTION) || (NO_CORRECTION == 0)
 		uint16_t microsTaken = nLeds * CLKS_TO_MICROS(24 * (T1 + T2 + T3));
 		MS_COUNTER += (microsTaken >> 10);
+#endif
 		sei();
 		mWait.mark();
 	}
diff --git a/controller.h b/controller.h
index ee2e6d62..cc9cd88e 100644
--- a/controller.h
+++ b/controller.h
@@ -120,7 +120,9 @@ public:
     CRGB getTemperature() { return m_ColorTemperature; }
 
     CRGB getAdjustment(uint8_t scale) { 
-        // if(1) return CRGB(scale,scale,scale);
+#if defined(NO_CORRECTION) && (NO_CORRECTION==1)
+        return CRGB(scale,scale,scale);
+#else
         CRGB adj(0,0,0);
 
         if(scale > 0) { 
@@ -136,6 +138,7 @@ public:
         }
 
         return adj;
+#endif
     }
 };
 
@@ -197,6 +200,7 @@ struct PixelController {
 #endif
 
         void init_binary_dithering() {
+#if !defined(NO_DITHERING) || (NO_DITHERING != 1)
                 static byte R = 0;
                 R++;
 
@@ -218,6 +222,7 @@ struct PixelController {
                         d[i] = scale8(Q, e[i]);
                         if(e[i]) e[i]--;
                 }
+#endif
         }
 
         // Do we have n pixels left to process?
diff --git a/lib8tion.h b/lib8tion.h
index d197b5a1..a2e70fe4 100644
--- a/lib8tion.h
+++ b/lib8tion.h
@@ -430,8 +430,31 @@ LIB8STATIC uint8_t sub8( uint8_t i, uint8_t j)
 LIB8STATIC uint8_t scale8( uint8_t i, fract8 scale) 
 {
 #if SCALE8_C == 1
-    return ((int)i * (int)(scale) ) >> 8;
+    return 
+    ((int)i * (int)(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"
@@ -446,6 +469,7 @@ LIB8STATIC uint8_t scale8( uint8_t i, fract8 scale)
 
     /* Return the result */
     return i;
+#endif
 #else
 #error "No implementation for scale8 available."
 #endif
@@ -459,7 +483,7 @@ LIB8STATIC uint8_t scale8( uint8_t i, fract8 scale)
 //  several additional cycles.
 LIB8STATIC uint8_t scale8_video( uint8_t i, fract8 scale)
 {
-#if SCALE8_C == 1
+#if SCALE8_C == 1 || defined(LIB8_ATTINY)
     uint8_t j = (((int)i * (int)scale) >> 8) + (i?1:0);
     // uint8_t nonzeroscale = (scale != 0) ? 1 : 0;
     // uint8_t j = (i == 0) ? 0 : (((int)i * (int)(scale) ) >> 8) + nonzeroscale;