#include "hw.h"
#include "mips.h"
#include "qemu-timer.h"

#define TIMER_FREQ	100 * 1000 * 1000

void cpu_mips_irqctrl_init (void)
{
}

/* XXX: do not use a global */
uint32_t cpu_mips_get_random (CPUState *env)
{
    static uint32_t seed = 0;
    uint32_t idx;
    seed = seed * 314159 + 1;
    idx = (seed >> 16) % (env->tlb->nb_tlb - env->CP0_Wired) + env->CP0_Wired;
    return idx;
}

/* MIPS R4K timer */
uint32_t cpu_mips_get_count (CPUState *env)
{
    if (env->CP0_Cause & (1 << CP0Ca_DC))
        return env->CP0_Count;
    else
        return env->CP0_Count +
            (uint32_t)muldiv64(qemu_get_clock(vm_clock),
                               TIMER_FREQ, ticks_per_sec);
}

static void cpu_mips_timer_update(CPUState *env)
{
    uint64_t now, next;
    uint32_t wait;

    now = qemu_get_clock(vm_clock);
    wait = env->CP0_Compare - env->CP0_Count -
	    (uint32_t)muldiv64(now, TIMER_FREQ, ticks_per_sec);
    next = now + muldiv64(wait, ticks_per_sec, TIMER_FREQ);
    qemu_mod_timer(env->timer, next);
}

void cpu_mips_store_count (CPUState *env, uint32_t count)
{
    if (env->CP0_Cause & (1 << CP0Ca_DC))
        env->CP0_Count = count;
    else {
        /* Store new count register */
        env->CP0_Count =
            count - (uint32_t)muldiv64(qemu_get_clock(vm_clock),
                                       TIMER_FREQ, ticks_per_sec);
        /* Update timer timer */
        cpu_mips_timer_update(env);
    }
}

void cpu_mips_store_compare (CPUState *env, uint32_t value)
{
    env->CP0_Compare = value;
    if (!(env->CP0_Cause & (1 << CP0Ca_DC)))
        cpu_mips_timer_update(env);
    if (env->insn_flags & ISA_MIPS32R2)
        env->CP0_Cause &= ~(1 << CP0Ca_TI);
    qemu_irq_lower(env->irq[(env->CP0_IntCtl >> CP0IntCtl_IPTI) & 0x7]);
}

void cpu_mips_start_count(CPUState *env)
{
    cpu_mips_store_count(env, env->CP0_Count);
}

void cpu_mips_stop_count(CPUState *env)
{
    /* Store the current value */
    env->CP0_Count += (uint32_t)muldiv64(qemu_get_clock(vm_clock),
                                         TIMER_FREQ, ticks_per_sec);
}

static void mips_timer_cb (void *opaque)
{
    CPUState *env;

    env = opaque;
#if 0
    if (logfile) {
        fprintf(logfile, "%s\n", __func__);
    }
#endif

    if (env->CP0_Cause & (1 << CP0Ca_DC))
        return;

    cpu_mips_timer_update(env);
    if (env->insn_flags & ISA_MIPS32R2)
        env->CP0_Cause |= 1 << CP0Ca_TI;
    qemu_irq_raise(env->irq[(env->CP0_IntCtl >> CP0IntCtl_IPTI) & 0x7]);
}

void cpu_mips_clock_init (CPUState *env)
{
    env->timer = qemu_new_timer(vm_clock, &mips_timer_cb, env);
    env->CP0_Compare = 0;
    cpu_mips_store_count(env, 1);
}