44 lines
699 B
C
44 lines
699 B
C
#include <stdint.h>
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// GPIO regs
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#define GPIO_BASE (0x40000000)
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#define GPIO_DATA (GPIO_BASE + (0x04))
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#define GPIO_REG(addr) (*((volatile uint32_t *)addr))
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#define MS(ms) (ms * 50000)
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#define read_csr(reg) ({ unsigned long __tmp; \
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asm volatile ("csrr %0, " #reg : "=r"(__tmp)); \
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__tmp; })
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static void delay_ms(uint32_t ms)
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{
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uint64_t tmp;
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uint64_t cycle;
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tmp = read_csr(cycle);
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tmp += (uint64_t)(read_csr(cycleh)) << 32;
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do {
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cycle = read_csr(cycle);
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cycle += (uint64_t)(read_csr(cycleh)) << 32;
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} while (cycle < tmp + MS(ms));
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}
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int main()
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{
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while (1) {
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GPIO_REG(GPIO_DATA) ^= 0x1;
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delay_ms(500);
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}
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}
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