37 lines
841 B
C
37 lines
841 B
C
#include <stdint.h>
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#define LEDS *((volatile uint32_t *) 0x00010000)
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#define UART_BAUD *((volatile uint32_t *) 0x00020000)
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#define UART_STATUS *((volatile uint32_t *) 0x00020004)
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#define UART_DATA *((volatile int32_t *) 0x00020008)
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#define UART_STATUS_TX_READY 0x1
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#define UART_STATUS_RX_READY 0x2
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#define BAUD_RATE 9600
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static void uart_puts(const char *str) {
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char c;
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while ((c = *str++)) {
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while (!(UART_STATUS & UART_STATUS_TX_READY));
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UART_DATA = c;
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}
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}
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static inline uint32_t rdcycle(void) {
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uint32_t cycle;
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asm volatile ("rdcycle %0" : "=r"(cycle));
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return cycle;
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}
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int main() {
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UART_BAUD = FREQ / BAUD_RATE;
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LEDS = 0xAA;
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for (;;) {
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uart_puts("Hello, world!\r\n");
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uint32_t start = rdcycle();
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while ((rdcycle() - start) <= FREQ);
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}
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}
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