Subversion Repositories neorv32

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// # << NEORV32: neorv32_cpu.c - CPU Core Functions HW Driver >>                                   #

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// # BSD 3-Clause License                                                                          #

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// # Copyright (c) 2020, Stephan Nolting. All rights reserved.                                     #

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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

// #################################################################################################

/**********************************************************************//**

 * @file neorv32_cpu.c

 * @author Stephan Nolting

 * @brief CPU Core Functions HW driver source file.

 **************************************************************************/

#include "neorv32.h"

#include "neorv32_cpu.h"

/**********************************************************************//**

 * Enable specific CPU interrupt.

 *

 * @note Interrupts have to be globally enabled via neorv32_cpu_eint(void), too.

 *

 * @param[in] irq_sel CPU interrupt select. See #NEORV32_CPU_MIE_enum.

 * @return 0 if success, 1 if error (invalid irq_sel).

 **************************************************************************/

int neorv32_cpu_irq_enable(uint8_t irq_sel) {

  if ((irq_sel != CPU_MIE_MSIE) && (irq_sel != CPU_MIE_MTIE) && (irq_sel != CPU_MIE_MEIE)) {

    return 1;

  }

  register uint32_t mask = (uint32_t)(1 << irq_sel);

  asm volatile ("csrrs zero, mie, %0" : : "r" (mask));

  return 0;

}

/**********************************************************************//**

 * Disable specific CPU interrupt.

 *

 * @param[in] irq_sel CPU interrupt select. See #NEORV32_CPU_MIE_enum.

 * @return 0 if success, 1 if error (invalid irq_sel).

 **************************************************************************/

int neorv32_cpu_irq_disable(uint8_t irq_sel) {

  if ((irq_sel != CPU_MIE_MSIE) && (irq_sel != CPU_MIE_MTIE) && (irq_sel != CPU_MIE_MEIE)) {

    return 1;

  }

  register uint32_t mask = (uint32_t)(1 << irq_sel);

  asm volatile ("csrrc zero, mie, %0" : : "r" (mask));

  return 0;

}

/**********************************************************************//**

 * Get cycle count from cycle[h].

 *

 * @note The cycle[h] CSR is shadowed copy of the mcycle[h] CSR.

 *

 * @return Current cycle counter (64 bit).

 **************************************************************************/

uint64_t neorv32_cpu_get_cycle(void) {

  union {

    uint64_t uint64;

    uint32_t uint32[sizeof(uint64_t)/2];

  } cycles;

  uint32_t tmp1, tmp2, tmp3;

  while(1) {

    tmp1 = neorv32_cpu_csr_read(CSR_CYCLEH);

    tmp2 = neorv32_cpu_csr_read(CSR_CYCLE);

    tmp3 = neorv32_cpu_csr_read(CSR_CYCLEH);

    if (tmp1 == tmp3) {

      break;

    }

  }

  cycles.uint32[0] = tmp2;

  cycles.uint32[1] = tmp3;

  return cycles.uint64;

}

/**********************************************************************//**

 * Set mcycle[h] counter.

 *

 * @param[in] value New value for mcycle[h] CSR (64-bit).

 **************************************************************************/

void neorv32_cpu_set_mcycle(uint64_t value) {

  union {

    uint64_t uint64;

    uint32_t uint32[sizeof(uint64_t)/2];

  } cycles;

  cycles.uint64 = value;

  neorv32_cpu_csr_write(CSR_MCYCLE,  0);

  neorv32_cpu_csr_write(CSR_MCYCLEH, cycles.uint32[1]);

  neorv32_cpu_csr_write(CSR_MCYCLE,  cycles.uint32[0]);

}

/**********************************************************************//**

 * Get retired instructions counter from instret[h].

 *

 * @note The instret[h] CSR is shadowed copy of the instret[h] CSR.

 *

 * @return Current instructions counter (64 bit).

 **************************************************************************/

uint64_t neorv32_cpu_get_instret(void) {

  union {

    uint64_t uint64;

    uint32_t uint32[sizeof(uint64_t)/2];

  } cycles;

  uint32_t tmp1, tmp2, tmp3;

  while(1) {

    tmp1 = neorv32_cpu_csr_read(CSR_INSTRETH);

    tmp2 = neorv32_cpu_csr_read(CSR_INSTRET);

    tmp3 = neorv32_cpu_csr_read(CSR_INSTRETH);

    if (tmp1 == tmp3) {

      break;

    }

  }

  cycles.uint32[0] = tmp2;

  cycles.uint32[1] = tmp3;

  return cycles.uint64;

}

/**********************************************************************//**

 * Set retired instructions counter minstret[h].

 *

 * @param[in] value New value for mcycle[h] CSR (64-bit).

 **************************************************************************/

void neorv32_cpu_set_minstret(uint64_t value) {

  union {

    uint64_t uint64;

    uint32_t uint32[sizeof(uint64_t)/2];

  } cycles;

  cycles.uint64 = value;

  neorv32_cpu_csr_write(CSR_MINSTRET,  0);

  neorv32_cpu_csr_write(CSR_MINSTRETH, cycles.uint32[1]);

  neorv32_cpu_csr_write(CSR_MINSTRET,  cycles.uint32[0]);

}

/**********************************************************************//**

 * Get current system time from time[h] CSR.

 *

 * @note This function requires the MTIME system timer to be implemented.

 *

 * @return Current system time (64 bit).

 **************************************************************************/

uint64_t neorv32_cpu_get_systime(void) {

  union {

    uint64_t uint64;

    uint32_t uint32[sizeof(uint64_t)/2];

  } cycles;

  uint32_t tmp1, tmp2, tmp3;

  while(1) {

    tmp1 = neorv32_cpu_csr_read(CSR_TIMEH);

    tmp2 = neorv32_cpu_csr_read(CSR_TIME);

    tmp3 = neorv32_cpu_csr_read(CSR_TIMEH);

    if (tmp1 == tmp3) {

      break;

    }

  }

  cycles.uint32[0] = tmp2;

  cycles.uint32[1] = tmp3;

  return cycles.uint64;

}

/**********************************************************************//**

 * Simple delay function (not very precise) using busy wait.

 *

 * @param[in] time_ms Time in ms to wait.

 **************************************************************************/

void neorv32_cpu_delay_ms(uint32_t time_ms) {

  uint32_t clock_speed = SYSINFO_CLK >> 10; // fake divide by 1000

  clock_speed = clock_speed >> 5; // divide by loop execution time (~30 cycles)

  uint32_t cnt = clock_speed * time_ms;

  // one iteration = ~30 cycles

  while (cnt) {

    asm volatile("nop");

    asm volatile("nop");

    asm volatile("nop");

    asm volatile("nop");

    cnt--;

  }

}