optimized Ethernet for speed

arduino-libraries#151
arduino-libraries#140

#define MAX_SOCK_NUM 4
#define ETHERNET_LARGE_BUFFERS

src/Ethernet.h

@@ -28,7 +28,7 @@
 // these "friend" classes are now defined in the same header file.  socket.h
 // was removed to avoid possible conflict with the C library header files.
 
-
+/*
 // Configure the maximum number of sockets to support.  W5100 chips can have
 // up to 4 sockets.  W5200 & W5500 can have up to 8 sockets.  Several bytes
 // of RAM are used for each socket.  Reducing the maximum can save RAM, but
@@ -38,14 +38,16 @@
 #else
 #define MAX_SOCK_NUM 8
 #endif
+*/
+#define MAX_SOCK_NUM 4
 
 // By default, each socket uses 2K buffers inside the Wiznet chip.  If
 // MAX_SOCK_NUM is set to fewer than the chip's maximum, uncommenting
 // this will use larger buffers within the Wiznet chip.  Large buffers
 // can really help with UDP protocols like Artnet.  In theory larger
 // buffers should allow faster TCP over high-latency links, but this
 // does not always seem to work in practice (maybe Wiznet bugs?)
-//#define ETHERNET_LARGE_BUFFERS
+#define ETHERNET_LARGE_BUFFERS
 
 
 #include <Arduino.h>

src/utility/w5100.cpp

@@ -413,9 +413,14 @@ uint16_t W5100Class::read(uint16_t addr, uint8_t *buf, uint16_t len)
 		cmd[1] = addr & 0xFF;
 		cmd[2] = (len >> 8) & 0x7F;
 		cmd[3] = len & 0xFF;
+#ifdef SPI_HAS_TRANSFER_BUF
+		SPI.transfer(cmd, NULL, 4);
+		SPI.transfer(NULL, buf, len);
+#else
 		SPI.transfer(cmd, 4);
 		memset(buf, 0, len);
 		SPI.transfer(buf, len);
+#endif
 		resetSS();
 	} else { // chip == 55
 		setSS();
@@ -457,9 +462,14 @@ uint16_t W5100Class::read(uint16_t addr, uint8_t *buf, uint16_t len)
 			cmd[2] = ((addr >> 6) & 0xE0) | 0x18; // 2K buffers
 			#endif
 		}
+#ifdef SPI_HAS_TRANSFER_BUF
+		SPI.transfer(cmd, NULL, 3);
+		SPI.transfer(NULL, buf, len);
+#else
 		SPI.transfer(cmd, 3);
 		memset(buf, 0, len);
 		SPI.transfer(buf, len);
+#endif
 		resetSS();
 	}
 	return len;
@@ -471,4 +481,4 @@ void W5100Class::execCmdSn(SOCKET s, SockCMD _cmd)
 	writeSnCR(s, _cmd);
 	// Wait for command to complete
 	while (readSnCR(s)) ;
-}
+}

src/utility/w5100.h

@@ -197,15 +197,22 @@ class W5100Class {
   __GP_REGISTER_N(SIPR,   0x000F, 4); // Source IP address
   __GP_REGISTER8 (IR,     0x0015);    // Interrupt
   __GP_REGISTER8 (IMR,    0x0016);    // Interrupt Mask
-  __GP_REGISTER16(RTR,    0x0017);    // Timeout address
-  __GP_REGISTER8 (RCR,    0x0019);    // Retry count
-  __GP_REGISTER8 (RMSR,   0x001A);    // Receive memory size (W5100 only)
-  __GP_REGISTER8 (TMSR,   0x001B);    // Transmit memory size (W5100 only)
-  __GP_REGISTER8 (PATR,   0x001C);    // Authentication type address in PPPoE mode
-  __GP_REGISTER8 (PTIMER, 0x0028);    // PPP LCP Request Timer
-  __GP_REGISTER8 (PMAGIC, 0x0029);    // PPP LCP Magic Number
-  __GP_REGISTER_N(UIPR,   0x002A, 4); // Unreachable IP address in UDP mode (W5100 only)
-  __GP_REGISTER16(UPORT,  0x002E);    // Unreachable Port address in UDP mode (W5100 only)
+
+// https://github.com/PaulStoffregen/Ethernet/issues/47
+// https://github.com/arduino-libraries/Ethernet/issues/84
+// https://github.com/arduino-libraries/Ethernet/issues/140
+
+  __GP_REGISTER16(RTR, 0x0019);           // Timeout address
+  __GP_REGISTER8 (RCR, 0x001B);           // Retry count
+  __GP_REGISTER8 (PTIMER, 0x001C);        // PPP LCP Request Timer
+  __GP_REGISTER8 (PMAGIC, 0x001D);        // PPP LCP Magic Number
+  __GP_REGISTER_N(PHAR, 0x001E, 6);       // PPP Destination MAC address
+  __GP_REGISTER16(PSID, 0x0024);          // PPP Session ID
+  __GP_REGISTER16(PMRU, 0x0026);          // PPP Maximum Segment Size
+  __GP_REGISTER_N(UIPR, 0x0028, 4);       // Unreachable IP address in UDP mode (W5500 only)
+  __GP_REGISTER16(UPORT, 0x002C);         // Unreachable Port address in UDP mode (W5500 only)
+  __GP_REGISTER8 (PHYCFGR_W5500, 0x002E); // PHY Configuration register, default: 10111xxx
+
   __GP_REGISTER8 (VERSIONR_W5200,0x001F);   // Chip Version Register (W5200 only)
   __GP_REGISTER8 (VERSIONR_W5500,0x0039);   // Chip Version Register (W5500 only)
   __GP_REGISTER8 (PSTATUS_W5200,     0x0035);    // PHY Status
@@ -456,7 +463,10 @@ extern W5100Class W5100;
 
 #ifndef htons
 
-#define htons(x) ( (((x)<<8)&0xFF00) | (((x)>>8)&0xFF) )
+//#define htons(x) ( (((x)<<8)&0xFF00) | (((x)>>8)&0xFF) )
+#define htons(x) ( ((( x )&0xFF)<<8) | ((( x )&0xFF00)>>8) )
+
+
 #define ntohs(x) htons(x)
 
 #define htonl(x) ( ((x)<<24 & 0xFF000000UL) | \