From: Kevin Townsend <kevin@ktownsend.com>
Date: Sat, 31 Mar 2012 23:37:41 +0000 (+0200)
Subject: Speed tweek for gpioSetValue
X-Git-Url: https://git.rohieb.name/hackover2013-badge-firmware.git/commitdiff_plain/3c19c7c8bd6b8c4d47bb3acba9e5b0ab2abe6a53

Speed tweek for gpioSetValue
---

diff --git a/core/gpio/gpio.c b/core/gpio/gpio.c
index a7154e1..89e4c95 100644
--- a/core/gpio/gpio.c
+++ b/core/gpio/gpio.c
@@ -284,26 +284,29 @@ void gpioSetValue (uint32_t portNum, uint32_t bitPos, uint32_t bitVal)
 {
   if (!_gpioInitialised) gpioInit();
 
-  // Get the appropriate register (handled this way to optimise code size)
-  REG32 *gpiodata = &GPIO_GPIO0DATA;
-  switch (portNum)
-  {
-    case 0:
-      gpiodata = &GPIO_GPIO0DATA;
-      break;
-    case 1:
-      gpiodata = &GPIO_GPIO1DATA;
-      break;
-    case 2:
-      gpiodata = &GPIO_GPIO2DATA;
-      break;
-    case 3:
-      gpiodata = &GPIO_GPIO3DATA;
-      break;
-  }
-
-  // Toggle value
-  bitVal == 1 ? (*gpiodata |= (1 << bitPos)) : (*gpiodata &= ~(1 << bitPos));
+  //  // Get the appropriate register (handled this way to optimise code size)
+  //  REG32 *gpiodata = &GPIO_GPIO0DATA;
+  //  switch (portNum)
+  //  {
+  //    case 0:
+  //      gpiodata = &GPIO_GPIO0DATA;
+  //      break;
+  //    case 1:
+  //      gpiodata = &GPIO_GPIO1DATA;
+  //      break;
+  //    case 2:
+  //      gpiodata = &GPIO_GPIO2DATA;
+  //      break;
+  //    case 3:
+  //      gpiodata = &GPIO_GPIO3DATA;
+  //      break;
+  //  }
+  //
+  //  // Toggle value
+  //  bitVal == 1 ? (*gpiodata |= (1 << bitPos)) : (*gpiodata &= ~(1 << bitPos));
+
+  // Take advantage of the fact the GPIO registers are bit-banded
+  (*(pREG32 ((GPIO_GPIO0_BASE + (portNum << 16)) + ((1 << bitPos) << 2)))) = bitVal ? 0xFFF : 0;
 }
 
 /**************************************************************************/