From: R. Steve McKown <rsmckown@gmail.com>
Date: Sat, 31 Dec 2011 19:09:13 +0000 (-0700)
Subject: Fix led_get(); reduce code size
X-Git-Tag: 1.1~8
X-Git-Url: https://oss.titaniummirror.com/gitweb?p=rgblamp.git;a=commitdiff_plain;h=ce6d400970d36cfb7ec4e3a2c97470d547c7ed78

Fix led_get(); reduce code size
---

diff --git a/main.c b/main.c
index a8f7324..627c94a 100644
--- a/main.c
+++ b/main.c
@@ -144,30 +144,37 @@ signed char bright = BRIGHT_INIT;
 bit bright_up;
 signed char pbHeldCount;
 
-/* Combine LED color value and brightness level to generate an RGB value */
-unsigned char led_get(unsigned value)
+/* Combine LED color value and brightness level to generate an RGB value.
+ * bright will be BRIGHT_MIN...BRIGHT_MAX
+ *
+ * @param value 0...1023 (6 bit color, left shifted 4 bits, for 10 bits)
+ * @param b brightness value BRIGHT_MIN...BRIGHT_MAX
+ * @return An RGB drive value, 0...255
+ */
+unsigned char led_get(int value, signed char b)
 {
-  unsigned char tmp = bright;
-
-  if (tmp > BRIGHT_MAX)
-    tmp = BRIGHT_MAX;
-  else if (tmp < BRIGHT_MIN)
-    tmp = BRIGHT_MIN;
-  return (value * tmp) >> 8;
+  return (unsigned long)value * b / 4 / BRIGHT_MAX;
 }
 
-/* Set the LEDs using both color and brightness values. */
+/* Set the LEDs using color values and current brightness. */
 void leds_set()
 {
-  rgb_set(led_get((red).value), led_get((grn).value), led_get((blu).value),
-      led_get((wht).value));
+  signed char b;
+
+  if (bright > BRIGHT_MAX)
+    b = BRIGHT_MAX;
+  else if (bright < BRIGHT_MIN)
+    b = BRIGHT_MIN;
+  else
+    b = bright;
+  rgb_set(led_get((red).value, b), led_get((grn).value, b),
+      led_get((blu).value, b), led_get((wht).value, b));
 }
 
 void start_fade()
 {
-  /* RGB PWM values are 8 bits, but computations are done in 15
-   * (leaving room for a sign bit), so leds_set() uses >>7 to convert
-   * to PWM values.
+  /* RGB PWM values are 8 bits.  Color values are 12 bits.  See led_get()
+   * for the conversion of color values and brightness to RGB values.
    */
   int newr, newg, newb, neww;