cpu.c

/* Check LICENSE file for copyright and license details. */

/*
 * CPU module
 *
 * Implementation a MIPS processor
 */

#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifdef INSTRDUMP
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#endif

/* Implements */
#include "cpu.h"

CPU            *CPU_create(uint32_t, uint32_t);
void            CPU_destroy(CPU *);

int64_t         CPU_mfc2(CPU *, uint32_t, uint32_t);
int             CPU_mtc2(CPU *, uint32_t, uint32_t, uint32_t);

/*
 * CPU_create: create CPU object
 *
 * ncpu: number of CPU to create
 * pc: initial program counter
 *
 * Returns array with ncpu cpus if success, NULL otherwise, errno
 * indicates the error. Each cpu on the array have its id on register K0.
 *
 * This function fails if:
 *	ENOMEM: Could not allocate CPU.
 *	ENOENT: Could not create debug file (if debuging is enabled).
 */
CPU *
CPU_create(uint32_t ncpu, uint32_t pc)
{
	size_t          i;

	CPU            *cpu;

	errno = 0;

	if (!(cpu = malloc(sizeof(CPU) * ncpu))) {
		errno = ENOMEM;
		return NULL;
	}

	memset(cpu, 0, sizeof(CPU) * ncpu);

	for (i = 0; i < ncpu; ++i) {
		cpu[i].pc      = pc;
		cpu[i].running = 1;
		cpu[i].gpr[K0] = i;
	}

#ifdef INSTRDUMP
	snprintf(cpu->debug.fname, 20, "cpu%04d_instrdump", id);
	if ((cpu->debug.fd = open(cpu->debug.fname,
				  O_CREAT | O_WRONLY | O_TRUNC,
				  S_IRUSR | S_IWUSR)) < 0) {
		warn("CPU_create -- open %s", cpu->debug.fname);
		errno = ENOENT;
		return NULL;
	}
#endif

	return cpu;
}

/*
 * CPU_destroy: free CPU object
 *
 * cpu: cpu object
 */
void
CPU_destroy(CPU *cpu)
{
#ifdef INSTRDUMP
	if (close(cpu->debug.fd)) {
		warn("CPU_destroy -- close %s", cpu->debug.fname);
	}
#endif
	free(cpu);
}

/*
 * CPU_mfc2: move from coprocessor 2
 *
 * cpu: cpu object
 * src: source register
 * sel: select
 *
 * Returns the contents of copressor 2 register if success, -1 otherwise, errno
 * indicates the error.
 *
 * This function fails if:
 *	EINVAL: Either src or sel are invalid values.
 */
int64_t
CPU_mfc2(CPU *cpu, uint32_t src, uint32_t sel)
{
	errno = 0;

	if (src >= COP2_NREG || sel >= COP2_NSEL) {
		errno = EINVAL;
		return -1;
	}

	return cpu->cop2[src][sel];
}

/*
 * CPU_mtc2: Move to coprocessor 2
 *
 * cpu:  cpu object
 * dest: destination register
 * sel:  select
 * val:  value to insert
 *
 * Returns 0 if success, an error code otherwise.
 *
 * This function fails if:
 *	EINVAL: Either src or sel are invalid values.
 */
int
CPU_mtc2(CPU *cpu, uint32_t dest, uint32_t sel, uint32_t val)
{
	errno = 0;

	if (dest >= COP2_NREG || sel >= COP2_NSEL) {
		return EINVAL;
	}

	cpu->cop2[dest][sel] = val;

	return 0;
}