1 files changed, 115 insertions, 0 deletions
diff --git a/F2024/coe718/labs/lab2/bitbanding/bitband.c b/F2024/coe718/labs/lab2/bitbanding/bitband.c
new file mode 100755
index 0000000..54c2b63
--- /dev/null
+++ b/F2024/coe718/labs/lab2/bitbanding/bitband.c
@@ -0,0 +1,115 @@
+#include "LPC17xx.h"
+#include "GLCD.h"
+
+#include <stdio.h>
+
+//------- ITM Stimulus Port definitions for printf ------------------- //
+#define ITM_Port8(n)    (*((volatile unsigned char *)(0xE0000000+4*n)))
+#define ITM_Port16(n)   (*((volatile unsigned short*)(0xE0000000+4*n)))
+#define ITM_Port32(n)   (*((volatile unsigned long *)(0xE0000000+4*n)))
+
+#define DEMCR           (*((volatile unsigned long *)(0xE000EDFC)))
+#define TRCENA          0x01000000
+
+struct __FILE { int handle;  };
+FILE __stdout;
+FILE __stdin;
+
+int fputc(int ch, FILE *f) {
+  if (DEMCR & TRCENA) {
+    while (ITM_Port32(0) == 0);
+    ITM_Port8(0) = ch;
+  }
+  return(ch);
+}
+//------------------------------------------------------------------- //
+
+#define __USE_LCD 0	// Uncomment to use the LCD
+#define __FI      1 // Font index 16x24 
+
+// Bit Band Macros used to calculate the alias address at run time
+#define ADDRESS(x)    (*((volatile unsigned long *)(x)))
+#define BitBand(x, y) 	ADDRESS(((unsigned long)(x) & 0xF0000000) | 0x02000000 |(((unsigned long)(x) & 0x000FFFFF) << 5) | ((y) << 2))
+
+#ifdef __USE_LCD
+static inline void method2lcd(unsigned char* msg) {
+  GLCD_DisplayString(6,  8, __FI,  msg);
+}
+#endif
+
+// Simple register masking
+static void method_mask(){
+	LPC_GPIO1->FIOPIN ^= (1 << 28);
+	LPC_GPIO2->FIOPIN ^= (1 << 2);
+}
+
+// Define pointer with bitband method
+static void method_function(){
+	volatile unsigned long* bit1 = &BitBand(&LPC_GPIO1->FIOPIN, 29);		
+	volatile unsigned long* bit2 = &BitBand(&LPC_GPIO2->FIOPIN, 3);		
+
+	static _Bool state = 1;
+	
+	*bit1 = *bit2 = state;
+	state = !state;
+}
+
+// Raw bitbanding
+static void method_bitbanding() {
+	const size_t addr1 = 0x22000000 + (0x2009C034 * 32UL) + (31 * 4);
+	const size_t addr2 = 0x22000000 + (0x2009C054 * 32UL) + (4 * 4);
+
+	static _Bool state = 1;
+	
+	ADDRESS(addr1) = ADDRESS(addr2) = state;
+	state = !state;
+}
+	
+void SysTick_Handler(void) { 
+	static size_t tick = 0;
+	static size_t state = 0;
+
+	if (tick++ < 500) { return; }
+	tick = 0;
+		
+	// Uses MOVS instruction to implement jump table
+	if 			(state == 0) { method_mask(); state++; }
+	else if (state == 1) { method_function(); state++; }
+	else if (state == 2) { method_bitbanding(); state = 0; }
+	
+	#ifdef __USE_LCD
+	if 			(state == 1) { method2lcd("MASK    "); }
+	else if (state == 2) { method2lcd("FUNCTION"); }
+	else if (state == 0) { method2lcd("BITBAND "); }	
+	#endif
+}
+	
+int main(void){
+	LPC_SC->PCONP     |= (1 << 15);            /* enable power to GPIO & IOCON  */
+  LPC_GPIO1->FIODIR |= 0xB0000000;           /* LEDs on PORT1 are output      */
+  LPC_GPIO2->FIODIR |= 0x0000007C;           /* LEDs on PORT2 are output			*/
+	
+	// Configure SysTick with interrupt and internal clock source
+	ADDRESS(0xE000E010) = (1 << 0) | (1 << 1) | (1 << 2);
+	
+	// Run handler every 1ms
+	ADDRESS(0xE000E014) = 99999;
+	
+	#ifdef __USE_LCD
+  GLCD_Init();                               /* Initialize graphical LCD (if enabled */
+
+  GLCD_Clear(White);                         /* Clear graphical LCD display   */
+  GLCD_SetBackColor(Blue);
+  GLCD_SetTextColor(Yellow);
+  GLCD_DisplayString(0, 0, __FI, "     COE718 Lab 2    ");
+	GLCD_SetTextColor(White);
+  GLCD_DisplayString(1, 0, __FI, "       bitband.c     ");
+  GLCD_DisplayString(2, 0, __FI, "  Watch the LEDs!    ");
+  GLCD_SetBackColor(White);
+  GLCD_SetTextColor(Blue);
+  GLCD_DisplayString(6, 0, __FI, "Method:");
+	#endif
+	
+	// Let SysTick callback run in background
+	while (1) {}
+}
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