From: Robin Krens <robin@robinkrens.nl>
Date: Fri, 19 Jul 2019 15:37:48 +0000 (+0800)
Subject: further ivt and isr implementation
X-Git-Url: https://robinkrens.nl/gitweb/?a=commitdiff_plain;h=36f2cc60f527235aaf1b3af0888f3255c0214030;p=cortex-from-scratch

further ivt and isr implementation

general (dummy) exception or interrupt handlers show exception number
(from VTOR status register)
---

diff --git a/include/mmap.h b/include/mmap.h
index d0f9338..6f4fabb 100644
--- a/include/mmap.h
+++ b/include/mmap.h
@@ -15,6 +15,7 @@
 
 /* SYSTEM CONTROL BLOCK REGISTER */
 #define SCB_VTOR ((volatile uint32_t *)( 0xE000ED08)) // VECTOR TABLE
+#define SCB_VTOR_ST ((volatile uint32_t *)( 0xE000ED04)) // STATUS OF VECTOR
 
 /* NESTED VECTOR INTERRUPT CONTROL REGISTER */
 #define NVIC_ISER0 ((volatile uint32_t*)( 0xE000E100)) // interrupt set enable register
diff --git a/ivt.c b/ivt.c
index 6df1e8b..183713f 100644
--- a/ivt.c
+++ b/ivt.c
@@ -32,36 +32,47 @@ struct interrupt_frame {
  * service routine:  
  *
  * interrupt vector 1-15: processor exceptions
- * interrupt vector 16-64: irq0 - irq ..
+ * interrupt vector 16-92: irq0 - irq ..
  * */
 
-uint32_t ivt[64];
+uint32_t ivt[92];
 
 /* each message corresponds to each and every exception. 
  * We get the correct message by accessing
  *  exception_message[interrupt_number] 
  *  exception_message[0] is not used (=MSP)*/
-unsigned char *exception_messages[] =
-{
-    "--",
-    "RESET",
-    "NMI",
-    "HARD FAULT",
-    "MEMMANAGE FAULT",
-    "BUS FAULT",
-    "USAGE FAULT",
-    "RESERVED",
-    "SVC",
-    "DEBUG MONITOR",
-    "RESERVED",
-    "PENDSV",
-    "SYSTICK",
-    "IRQ1",
-    "IRQ2",
-    "IRQ3",
-    "IRQ4",
-    // add more if needed
-};
+
+char * exception_message(uint8_t intnr) {
+
+	char * messages[] = {
+	    "--",
+	    "RESET",
+	    "NMI",
+	    "HARD FAULT",
+	    "MEMMANAGE FAULT",
+	    "BUS FAULT",
+	    "USAGE FAULT",
+	    "RESERVED",
+	    "SVC",
+	    "DEBUG MONITOR",
+	    "RESERVED",
+	    "RESERVED",
+	    "RESERVED",
+	    "RESERVED",
+	    "PENDSV",
+	    "SYSTICK",
+	    "IRQ1",
+	    "IRQ2",
+	    "IRQ3",
+	    "IRQ4",
+	    // add more if needed
+	};
+
+	if (intnr < 20) // TODO: strlen
+		return messages[intnr];
+
+	return NULL;
+}
 
 void ivt_set_gate(unsigned char num, void * isr(), short pri) {
 
@@ -75,21 +86,11 @@ void ivt_set_gate(unsigned char num, void * isr(), short pri) {
 __attribute__ ((interrupt)) 
 void * dummy_isr(struct interrupt_frame * frame) {
 
-
-	uint32_t * p = (volatile uint32_t *) 0x21000000;
-
-	addrtohex(frame->r0);
-	addrtohex(frame->r1);
-	addrtohex(frame->r2);
-	addrtohex(frame->r3);
-	addrtohex(frame->r12);
-	addrtohex(frame->lr);
-	addrtohex(frame->pc);
-	addrtohex(frame->psr);
+	uint8_t nr = *SCB_VTOR_ST & 0xFF;
 	
-	//__asm__ __volatile__ ("MRS r0, IPSR");
-	//addrtohex(frame->r0);
-	uart_puts("EXCEPTION X: SYSTEM HALTED\n");
+	uart_puts("EXCEPTION: ");
+	uart_puts(exception_message(nr));
+	uart_puts("\nSYSTEM HALTED\n");
 	
 	for(;;);
 }
@@ -98,13 +99,13 @@ void * dummy_isr(struct interrupt_frame * frame) {
 void ivt_init() {
 
 	/* clear entiry IVT, in SRAM location for SRAM + .data (in .bss section) */
-	memset(&ivt, 0, (sizeof(uint32_t) * 87));
+	memset(&ivt, 0, (sizeof(uint32_t) * 92));
 
 	// stack top is loaded from the first entry table on boot/reset
 	// don't need to relocate or init this here
 	extern void * reset,  * nmi, * hardfault;
 
-	for (int i = 1; i < 7; i++) {
+	for (int i = 1; i <= 6 ; i++) {
 		ivt_set_gate(i, dummy_isr, 0);
 	}
 
diff --git a/link.ld b/link.ld
index 8301b2c..085ab79 100644
--- a/link.ld
+++ b/link.ld
@@ -14,9 +14,9 @@ SECTIONS
 	{
 		/* (.vector_table */ 
 		*(.text)
-
-	} 
-	. = 0x20000000;
+		*(.rodata)
+	}
+        . = 0x20000000;	
 	.data :  
 	{
 		*(.data)
@@ -24,5 +24,6 @@ SECTIONS
 	.bss : ALIGN(256)
 	{
 		*(.bss)
-	} 
+	}
+       	_endofbss = .;	
 }
diff --git a/main.c b/main.c
index 4134c95..c8a47aa 100644
--- a/main.c
+++ b/main.c
@@ -46,8 +46,8 @@ void main()
 	ivt_init();
 //	clock_init();
 	uart_init();
-//	systick_init();
 	uart_puts("LOADING SYSTEM 0.1 ...\n");
+	systick_init();
 	sysinfo();
 	mm_init();
 
@@ -61,11 +61,6 @@ void main()
 	//regw_u32(p, 0x0CCCCCCCC, 4, 0x01);
 
 	//regw_u8(p, 0xFF, 0, 0x02);
-	
-	//addrtohex(*p);
-
-	//addrtohex((volatile uint32_t) 0x12345678 );
-	//addrtohex((volatile uint32_t) SCB_VTOR );
 
 //	asm("cpsie i"); // enable irq , cpsied f (disable faukts(
 
diff --git a/start.asm b/start.asm
index d8c7244..e4ca237 100644
--- a/start.asm
+++ b/start.asm
@@ -34,7 +34,7 @@ stub:
 	mov R1,#0
 	udiv.w R2, R0, R1 */
 
-/*	.data
-	.word 'x' */
+	.data
+	.word 'x' 
 	.end
 
diff --git a/systick.c b/systick.c
index 48065ef..e90714a 100644
--- a/systick.c
+++ b/systick.c
@@ -16,19 +16,11 @@ struct interrupt_frame {
         uint32_t psr; // N-4
 };
 
-
-/* void * systick_handler() {
-
-//	*RANDOM_ADDR = (volatile uint32_t) 0x10101010 ;
-//	uart_puts("TEST");
-} */
-
 __attribute__ ((interrupt))
 void * systick_handler(struct interrupt_frame * frame) {
 
+	uint32_t volatile status;
 	uart_puts("TICKING\n");
-//	addrtohex((uint32_t) 0x12345678);
-	//      for(;;);
 }
 
 
@@ -41,7 +33,7 @@ void systick_init() {
 	/* The counter reload register here holds 
 	 * 0x1000 -- that's 4096 clock cycles -- if 
 	 * it is down to zero it is restores the value */
-	*STK_RELOAD = (volatile uint32_t) 0x00000400; 
+	*STK_RELOAD = (volatile uint32_t) 0x00400000; 
 
 	/* Every time the counter counts down to zero
 	 * a systick exception is asserted. Systick has
diff --git a/uart.c b/uart.c
index 4751645..86bf9fe 100644
--- a/uart.c
+++ b/uart.c
@@ -12,13 +12,14 @@
 
 void * uart_handler() {
 
-	uart_puts("\n echo: ");
+	uart_puts("echo: ");
  	while (RXNE) {
 		char echochar = *USART1_DR;
-	//	regw_u8(USART1_DR, echochar, 0, O_WRITE);
-	uart_putc(echochar);
-	}  
-//for(;;);
+		//regw_u32(USART1_DR, echochar, 0, O_WRITE);
+		uart_putc(echochar);
+	}
+	uart_putc('\n');
+      		
 
 }
 void uart_init() {