You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
////////////////////////////////////////////////////////////////
|
|
// NOTE: this contains the code that intentionally CORRUPTS
|
|
// and eventually overflows the stack as explained in the
|
|
// Lesson-10 video.
|
|
|
|
#include "tm4c.h" // the same as "lm4f120h5qr.h" in the video
|
|
#include "delay.h"
|
|
|
|
#define LED_RED (1U << 1)
|
|
#define LED_BLUE (1U << 2)
|
|
#define LED_GREEN (1U << 3)
|
|
|
|
unsigned fact(unsigned n);
|
|
|
|
int main(void) {
|
|
unsigned volatile x;
|
|
|
|
x = fact(0U);
|
|
x = 2U + 3U*fact(1U);
|
|
x = fact(9U); // <== corrupts and overflows the stack!
|
|
|
|
SYSCTL_GPIOHBCTL_R |= (1U << 5); /* enable AHB for GPIOF */
|
|
SYSCTL_RCGCGPIO_R |= (1U << 5); /* enable clock for GPIOF */
|
|
|
|
GPIO_PORTF_AHB_DIR_R |= (LED_RED | LED_BLUE | LED_GREEN);
|
|
GPIO_PORTF_AHB_DEN_R |= (LED_RED | LED_BLUE | LED_GREEN);
|
|
|
|
GPIO_PORTF_AHB_DATA_BITS_R[LED_BLUE] = LED_BLUE;
|
|
while (1) {
|
|
GPIO_PORTF_AHB_DATA_BITS_R[LED_RED] = LED_RED;
|
|
|
|
delay(1000000);
|
|
|
|
GPIO_PORTF_AHB_DATA_BITS_R[LED_RED] = 0;
|
|
|
|
delay(500000);
|
|
}
|
|
//return 0; // unreachable code
|
|
}
|
|
|
|
unsigned fact(unsigned n) {
|
|
// 0! = 1
|
|
// n! = n*(n-1)! for n > 0
|
|
unsigned foo[6];
|
|
foo[n] = n;
|
|
|
|
if (n == 0U) {
|
|
return 1U;
|
|
}
|
|
else {
|
|
return foo[n] * fact(n - 1U);
|
|
}
|
|
}
|
|
|
|
////////////////////////////////////////////////////////////////
|
|
// NOTE: the file main_swap.c in the project directory contains
|
|
// the code tat uses the swap() function to illustrate the use
|
|
// of pointer parameters in Lesson-10 video.
|