From bdfafbcf9f7d247b85699818cd2a959178a24b64 Mon Sep 17 00:00:00 2001
From: ergosys <ergosys@gmail.com>
Date: Fri, 12 Dec 2014 15:27:37 -0800
Subject: [PATCH] slightly faster flush and clear

---
 drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c b/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
index 9670d2d0..2386c2d4 100644
--- a/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
+++ b/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
@@ -14,6 +14,7 @@
 #include "src/gdisp/driver.h"
 
 #include "board_SSD1306.h"
+#include <string.h>   // for memset
 
 /*===========================================================================*/
 /* Driver local definitions.                                                 */
@@ -136,17 +137,22 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 
 #if GDISP_HARDWARE_FLUSH
 	LLDSPEC void gdisp_lld_flush(GDisplay *g) {
-		unsigned	i;
+		uint8_t * ram;
+		unsigned pages;
 
 		// Don't flush if we don't need it.
 		if (!(g->flags & GDISP_FLG_NEEDFLUSH))
 			return;
+		ram = RAM(g);
+		pages = GDISP_SCREEN_HEIGHT/8;
 
 		acquire_bus(g);
 		write_cmd(g, SSD1306_SETSTARTLINE | 0);
 
-		for(i=0; i < GDISP_SCREEN_HEIGHT/8 * SSD1306_PAGE_WIDTH; i+=SSD1306_PAGE_WIDTH)
-			write_data(g, RAM(g)+i, SSD1306_PAGE_WIDTH);
+		while (pages--) {
+			write_data(g, ram, SSD1306_PAGE_WIDTH);
+			ram += SSD1306_PAGE_WIDTH;
+		}
 		release_bus(g);
 	}
 #endif
@@ -155,9 +161,8 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 	LLDSPEC void gdisp_lld_clear(GDisplay *g) {
 		uint8_t fill = (g->p.color == Black) ? 0 : 0xff;
 		int bytes = GDISP_SCREEN_WIDTH * GDISP_SCREEN_HEIGHT/8;
-		int off;
-		for (off = 0; off < bytes; off++)
-			RAM(g)[off] = fill;
+		memset(RAM(g), fill, bytes);
+		g->flags |= GDISP_FLG_NEEDFLUSH;
 	}
 #endif