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__attribute__((always_inline))
static inline void print_int8(volatile char *uart, unsigned x)
{
*uart = ((x >> 4) & 0xf) + '0';
*uart = ((x >> 0) & 0xf) + '0';
}
__attribute__((always_inline))
static inline void print_addr(volatile char *uart, unsigned x, unsigned y)
{
*uart = '(';
print_int8(uart, x);
*uart = ',';
*uart = ' ';
print_int8(uart, y);
*uart = ')';
*uart = '\n';
}
__attribute__((always_inline))
static inline unsigned wrap(unsigned x, unsigned X)
{
return x + 1 >= X ? 0 : x + 1;
}
__attribute__((always_inline))
static inline unsigned next_idx(unsigned x, unsigned y, unsigned X, unsigned Y)
{
unsigned yi = wrap(y, Y);
unsigned xi = yi < y ? wrap(x, X) : x;
return (xi << 16) | yi;
}
void _start(unsigned x, unsigned y, unsigned X, unsigned Y)
{
volatile char *uart = (char *)4096;
volatile unsigned *control = (unsigned *)(1ULL << 56);
if (x == 0 && y == 2) {
goto do_work;
} else {
while (*control != ((x << 16) | y)) {}
}
do_work:
print_addr(uart, x, y);
*control = next_idx(x, y, X, Y);
if (x == X - 1 && y == Y - 1)
asm ("ebreak");
/* otherwise just loop */
while (1) {}
}
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