mirror of https://github.com/YosysHQ/picorv32.git
29 lines
583 B
C
29 lines
583 B
C
#include <stdint.h>
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#define SHIFT_COUNTER_BITS 16
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void output(uint8_t c)
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{
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*(volatile char*)0x10000000 = c;
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}
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void output_gray(uint8_t c)
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{
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unsigned int in_buf = c, out_buf = 0;
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for (int i = 0; i < 8; i++) {
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unsigned int bit = (in_buf & 1) ^ ((in_buf >> 1) & 1);
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in_buf = in_buf >> 1;
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out_buf = (out_buf << 1) | bit;
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}
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output(out_buf);
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}
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void main()
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{
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for (uint32_t counter = (2+4+32+64) << SHIFT_COUNTER_BITS;; counter++) {
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asm volatile ("" : : "r"(counter));
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if ((counter & ~(~0 << SHIFT_COUNTER_BITS)) == 0)
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output_gray(counter >> SHIFT_COUNTER_BITS);
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}
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}
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