43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
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#include "tb_cxxrtl_io.h"
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#include "hazard3_irq.h"
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#define MAX_PRIORITY 15
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#define NUM_IRQS 64
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extern uintptr_t _external_irq_table[NUM_IRQS];
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void handler(void);
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int main() {
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// Enable external IRQs globally
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set_csr(mstatus, 0x8);
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set_csr(mie, 0x800);
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// Enable one external IRQ at each priority level
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for (int i = 0; i <= MAX_PRIORITY; ++i) {
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h3irq_enable(i, true);
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h3irq_set_priority(i, i);
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_external_irq_table[i] = (uintptr_t)handler;
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}
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// Set off the lowest-priority IRQ. The IRQ handler will then set the
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// next-lowest, which will preempt it. So on, up to the highest level,
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// then return all the way back down through the nested frames.
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tb_puts("Posting first IRQ\n");
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tb_set_irq_masked(0x1);
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asm ("wfi");
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tb_puts("Done.\n");
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return 0;
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}
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void handler(void) {
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int irqnum = h3irq_get_current_irq();
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tb_printf("Entered IRQ %d\n", irqnum);
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if (irqnum < MAX_PRIORITY)
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tb_set_irq_masked(1u << (irqnum + 1));
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// !!! Get preempted here
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tb_clr_irq_masked(1u << irqnum);
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// Make sure context save/restore tracks as expected:
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irqnum = h3irq_get_current_irq();
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tb_printf("Exiting IRQ %d\n", irqnum);
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}
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