From 7017969f6bd92b8ffecc05fa6f9ec1ed24c78f9b Mon Sep 17 00:00:00 2001
From: Micah Elizabeth Scott <micah@scanlime.org>
Date: Tue, 23 Jul 2013 15:30:44 -0700
Subject: [PATCH] Revert "Framebuffer iterator scheme, to avoid division"
This reverts commit 07106959f6340912fc47c94ee40cc072479ec44e.
---
firmware/fadecandy.cpp | 79 ++++++++++--------------------------------
firmware/fc_usb.h | 40 ++-------------------
2 files changed, 21 insertions(+), 98 deletions(-)
diff --git a/firmware/fadecandy.cpp b/firmware/fadecandy.cpp
index 7e7df52..3eaa5ec 100644
--- a/firmware/fadecandy.cpp
+++ b/firmware/fadecandy.cpp
@@ -54,7 +54,7 @@ ALWAYS_INLINE static inline uint32_t lutInterpolate(const uint16_t *lut, uint32_
return (lut[index] * invAlpha + lut[index + 1] * alpha) >> 8;
}
-static inline uint32_t updatePixel(uint32_t icPrev, uint32_t icNext, fcFramebufferIter iter)
+static inline uint32_t updatePixel(uint32_t icPrev, uint32_t icNext, unsigned n)
{
/*
* Update pipeline for one pixel:
@@ -64,8 +64,8 @@ static inline uint32_t updatePixel(uint32_t icPrev, uint32_t icNext, fcFramebuff
* 3. Dithering
*/
- const uint8_t *pixelPrev = buffers.fbPrev->pixel(iter);
- const uint8_t *pixelNext = buffers.fbNext->pixel(iter);
+ const uint8_t *pixelPrev = buffers.fbPrev->pixel(n);
+ const uint8_t *pixelNext = buffers.fbNext->pixel(n);
// Per-channel linear interpolation and conversion to 16-bit color.
int iR = (pixelPrev[0] * icPrev + pixelNext[0] * icNext) >> 16;
@@ -78,7 +78,7 @@ static inline uint32_t updatePixel(uint32_t icPrev, uint32_t icNext, fcFramebuff
iB = lutInterpolate(&buffers.lutCurrent[2 * 256], iB);
// Pointer to the residual buffer for this pixel
- int8_t *pResidual = &residual[iter.component];
+ int8_t *pResidual = &residual[n * 3];
// Incorporate the residual from last frame
iR += pResidual[0];
@@ -133,30 +133,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
uint32_t icPrev = 257 * (0x10000 - interpCoefficient);
uint32_t icNext = 257 * interpCoefficient;
- /*
- * Iterators for each LED strip. (Avoids division later on).
- *
- * We set these to one LED prior to the one we actually want to start with,
- * since it makes for more efficient register usage later on if we pre-increment
- * instead of post-incrementing.
- */
-
- fcFramebufferIter i0, i1, i2, i3, i4, i5, i6, i7;
-
- i0.setNegativeOne();
- i1.set(LEDS_PER_STRIP * 1 - 1);
- i2.set(LEDS_PER_STRIP * 2 - 1);
- i3.set(LEDS_PER_STRIP * 3 - 1);
- i4.set(LEDS_PER_STRIP * 4 - 1);
- i5.set(LEDS_PER_STRIP * 5 - 1);
- i6.set(LEDS_PER_STRIP * 6 - 1);
- i7.set(LEDS_PER_STRIP * 7 - 1);
-
- /*
- * Process each LED strip in parallel, and re-pack into a planar DMA buffer.
- */
-
- for (int i = 0; i < LEDS_PER_STRIP; ++i, out += 6) {
+ for (int i = 0; i < LEDS_PER_STRIP; ++i) {
// Six output words
union {
@@ -174,8 +151,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
* This generates fairly efficient code using the UBFX and BFI instructions.
*/
- i0.next();
- uint32_t p0 = updatePixel(icPrev, icNext, i0);
+ uint32_t p0 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p0d = p0;
o5.p0c = p0 >> 1;
@@ -202,8 +178,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p0b = p0 >> 22;
o0.p0a = p0 >> 23;
- i1.next();
- uint32_t p1 = updatePixel(icPrev, icNext, i1);
+ uint32_t p1 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p1d = p1;
o5.p1c = p1 >> 1;
@@ -230,8 +205,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p1b = p1 >> 22;
o0.p1a = p1 >> 23;
- i2.next();
- uint32_t p2 = updatePixel(icPrev, icNext, i2);
+ uint32_t p2 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p2d = p2;
o5.p2c = p2 >> 1;
@@ -258,8 +232,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p2b = p2 >> 22;
o0.p2a = p2 >> 23;
- i3.next();
- uint32_t p3 = updatePixel(icPrev, icNext, i3);
+ uint32_t p3 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p3d = p3;
o5.p3c = p3 >> 1;
@@ -286,8 +259,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p3b = p3 >> 22;
o0.p3a = p3 >> 23;
- i4.next();
- uint32_t p4 = updatePixel(icPrev, icNext, i4);
+ uint32_t p4 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p4d = p4;
o5.p4c = p4 >> 1;
@@ -314,8 +286,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p4b = p4 >> 22;
o0.p4a = p4 >> 23;
- i5.next();
- uint32_t p5 = updatePixel(icPrev, icNext, i5);
+ uint32_t p5 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p5d = p5;
o5.p5c = p5 >> 1;
@@ -342,8 +313,7 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p5b = p5 >> 22;
o0.p5a = p5 >> 23;
- i6.next();
- uint32_t p6 = updatePixel(icPrev, icNext, i6);
+ uint32_t p6 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p6d = p6;
o5.p6c = p6 >> 1;
@@ -370,50 +340,39 @@ static void updateDrawBuffer(unsigned interpCoefficient)
o0.p6b = p6 >> 22;
o0.p6a = p6 >> 23;
- i7.next();
- uint32_t p7 = updatePixel(icPrev, icNext, i7);
+ uint32_t p7 = updatePixel(icPrev, icNext, i + LEDS_PER_STRIP * 0);
o5.p7d = p7;
o5.p7c = p7 >> 1;
o5.p7b = p7 >> 2;
o5.p7a = p7 >> 3;
-
- out[5] = o5.word;
-
o4.p7d = p7 >> 4;
o4.p7c = p7 >> 5;
o4.p7b = p7 >> 6;
o4.p7a = p7 >> 7;
-
- out[4] = o4.word;
-
o3.p7d = p7 >> 8;
o3.p7c = p7 >> 9;
o3.p7b = p7 >> 10;
o3.p7a = p7 >> 11;
-
- out[3] = o3.word;
-
o2.p7d = p7 >> 12;
o2.p7c = p7 >> 13;
o2.p7b = p7 >> 14;
o2.p7a = p7 >> 15;
-
- out[2] = o2.word;
-
o1.p7d = p7 >> 16;
o1.p7c = p7 >> 17;
o1.p7b = p7 >> 18;
o1.p7a = p7 >> 19;
-
- out[1] = o1.word;
-
o0.p7d = p7 >> 20;
o0.p7c = p7 >> 21;
o0.p7b = p7 >> 22;
o0.p7a = p7 >> 23;
- out[0] = o0.word;
+ *(out++) = o0.word;
+ *(out++) = o1.word;
+ *(out++) = o2.word;
+ *(out++) = o3.word;
+ *(out++) = o4.word;
+ *(out++) = o5.word;
}
}
diff --git a/firmware/fc_usb.h b/firmware/fc_usb.h
index ffe47f5..ba9a9d3 100644
--- a/firmware/fc_usb.h
+++ b/firmware/fc_usb.h
@@ -62,51 +62,15 @@ struct fcPacketBuffer
};
-/*
- * Iterator referring to one pixel in the framebuffer
- */
-
-struct fcFramebufferIter
-{
- unsigned packet;
- unsigned index;
- unsigned component;
-
- ALWAYS_INLINE void setNegativeOne()
- {
- // Special case: After one call to next(), this points to LED #0.
- index = -1;
- packet = 0;
- component = -3;
- }
-
- ALWAYS_INLINE void set(unsigned led)
- {
- packet = led / PIXELS_PER_PACKET;
- index = 1 + (led % PIXELS_PER_PACKET) * 3;
- component = led * 3;
- }
-
- ALWAYS_INLINE void next()
- {
- if (++index >= (1 + PIXELS_PER_PACKET * 3)) {
- index = 0;
- packet++;
- }
- component += 3;
- }
-};
-
-
/*
* Framebuffer
*/
struct fcFramebuffer : public fcPacketBuffer<PACKETS_PER_FRAME>
{
- ALWAYS_INLINE const uint8_t* pixel(fcFramebufferIter iter) const
+ ALWAYS_INLINE const uint8_t* pixel(unsigned index)
{
- return &packets[iter.packet]->buf[iter.index];
+ return &packets[index / PIXELS_PER_PACKET]->buf[1 + (index % PIXELS_PER_PACKET) * 3];
}
};
--
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