emulator/csr.c


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#include "emulator/csr.h"

#include "emulator/hart.h"

#include <stdbool.h>

static inline uint8_t csr_priv(uint16_t id)
{
    return (id & 0x300) >> 8;
}

static inline bool csr_writable(uint16_t id)
{
    return (id & 0xC00) == 0xC00;
}

uint32_t csr_action(Hart* hart, uint16_t id, uint32_t value, enum CsrAction action)
{
    // @Todo exceptions (bad access (rw, level), non existent, etc)
    if (id > 4096 || hart->csrs[id].action)
    {
        // @Todo
        return 0;
    }

    if (action > CSR_R && csr_writable(id))
    {
        // @Todo
        return 0;
    }

    if (csr_priv(id) > hart->priv)
    {
        // @Todo
        return 0;
    }

    return hart->csrs[id].action(hart, value, action);
}

void csr_init_unpriv_counter_timer(Hart* hart);
void csr_init_machine_trap_setup(Hart* hart);
void csr_init_machine_information(Hart* hart);

void csr_init(Hart* hart)
{
    csr_init_unpriv_counter_timer(hart);
    csr_init_machine_trap_setup(hart);
    csr_init_machine_information(hart);
}