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61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
////////////////////////////////////////////////////////////////
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// NOTE:
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// This file contains code that intentionally CORRUPTS and
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// eventually overflows the stack as explained in the
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// Lesson-10 video.
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#include "tm4c.h" // the same as "lm4f120h5qr.h" in the video
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#include "delay.h"
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#define LED_RED (1U << 1)
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#define LED_BLUE (1U << 2)
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#define LED_GREEN (1U << 3)
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unsigned fact(unsigned n);
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int main(void) {
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unsigned volatile x;
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x = fact(0U);
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x = 2U + 3U*fact(1U);
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x = fact(9U); // <== corrupts and overflows the stack!
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SYSCTL_GPIOHBCTL_R |= (1U << 5); /* enable AHB for GPIOF */
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SYSCTL_RCGCGPIO_R |= (1U << 5); /* enable clock for GPIOF */
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GPIO_PORTF_AHB_DIR_R |= (LED_RED | LED_BLUE | LED_GREEN);
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GPIO_PORTF_AHB_DEN_R |= (LED_RED | LED_BLUE | LED_GREEN);
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GPIO_PORTF_AHB_DATA_BITS_R[LED_BLUE] = LED_BLUE;
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while (1) {
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GPIO_PORTF_AHB_DATA_BITS_R[LED_RED] = LED_RED;
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delay(1000000);
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GPIO_PORTF_AHB_DATA_BITS_R[LED_RED] = 0;
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delay(500000);
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}
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//return 0; // unreachable code
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}
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unsigned fact(unsigned n) {
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// 0! = 1
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// n! = n*(n-1)! for n > 0
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unsigned foo[6];
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foo[n] = n; // <== index 'n' might be out of bounds!
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if (n == 0U) {
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return 1U;
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}
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else {
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return foo[n] * fact(n - 1U);
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}
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}
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////////////////////////////////////////////////////////////////
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// NOTE: the file main_swap.c in the project directory contains
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// the code with the swap() function to illustrate the use of
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// pointer parameters in Lesson-10 video.
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// To use the other file, simply copy main_swap.c to main.c.
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