There are a number of ffs(3) callers that do roughly:
  bit = ffs(val);
  if (bit) {
      do_something(bit - 1);
  }
This pattern can be converted to ctz32() like this:
  zeroes = ctz32(val);
  if (zeroes != 32) {
      do_something(zeroes);
  }
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427124571-28598-6-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
		
	
			
		
			
				
	
	
		
			213 lines
		
	
	
		
			6.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			213 lines
		
	
	
		
			6.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
 | 
						|
 * Allwinner A10 interrupt controller device emulation
 | 
						|
 *
 | 
						|
 * Copyright (C) 2013 Li Guang
 | 
						|
 * Written by Li Guang <lig.fnst@cn.fujitsu.com>
 | 
						|
 *
 | 
						|
 * This program is free software; you can redistribute it and/or modify it
 | 
						|
 * under the terms of the GNU General Public License as published by the
 | 
						|
 * Free Software Foundation; either version 2 of the License, or
 | 
						|
 * (at your option) any later version.
 | 
						|
 *
 | 
						|
 * This program is distributed in the hope that it will be useful, but WITHOUT
 | 
						|
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 | 
						|
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 | 
						|
 * for more details.
 | 
						|
 */
 | 
						|
 | 
						|
#include "hw/sysbus.h"
 | 
						|
#include "hw/devices.h"
 | 
						|
#include "sysemu/sysemu.h"
 | 
						|
#include "hw/intc/allwinner-a10-pic.h"
 | 
						|
 | 
						|
static void aw_a10_pic_update(AwA10PICState *s)
 | 
						|
{
 | 
						|
    uint8_t i;
 | 
						|
    int irq = 0, fiq = 0, zeroes;
 | 
						|
 | 
						|
    s->vector = 0;
 | 
						|
 | 
						|
    for (i = 0; i < AW_A10_PIC_REG_NUM; i++) {
 | 
						|
        irq |= s->irq_pending[i] & ~s->mask[i];
 | 
						|
        fiq |= s->select[i] & s->irq_pending[i] & ~s->mask[i];
 | 
						|
 | 
						|
        if (!s->vector) {
 | 
						|
            zeroes = ctz32(s->irq_pending[i] & ~s->mask[i]);
 | 
						|
            if (zeroes != 32) {
 | 
						|
                s->vector = (i * 32 + zeroes) * 4;
 | 
						|
            }
 | 
						|
        }
 | 
						|
    }
 | 
						|
 | 
						|
    qemu_set_irq(s->parent_irq, !!irq);
 | 
						|
    qemu_set_irq(s->parent_fiq, !!fiq);
 | 
						|
}
 | 
						|
 | 
						|
static void aw_a10_pic_set_irq(void *opaque, int irq, int level)
 | 
						|
{
 | 
						|
    AwA10PICState *s = opaque;
 | 
						|
 | 
						|
    if (level) {
 | 
						|
        set_bit(irq % 32, (void *)&s->irq_pending[irq / 32]);
 | 
						|
    } else {
 | 
						|
        clear_bit(irq % 32, (void *)&s->irq_pending[irq / 32]);
 | 
						|
    }
 | 
						|
    aw_a10_pic_update(s);
 | 
						|
}
 | 
						|
 | 
						|
static uint64_t aw_a10_pic_read(void *opaque, hwaddr offset, unsigned size)
 | 
						|
{
 | 
						|
    AwA10PICState *s = opaque;
 | 
						|
    uint8_t index = (offset & 0xc) / 4;
 | 
						|
 | 
						|
    switch (offset) {
 | 
						|
    case AW_A10_PIC_VECTOR:
 | 
						|
        return s->vector;
 | 
						|
    case AW_A10_PIC_BASE_ADDR:
 | 
						|
        return s->base_addr;
 | 
						|
    case AW_A10_PIC_PROTECT:
 | 
						|
        return s->protect;
 | 
						|
    case AW_A10_PIC_NMI:
 | 
						|
        return s->nmi;
 | 
						|
    case AW_A10_PIC_IRQ_PENDING ... AW_A10_PIC_IRQ_PENDING + 8:
 | 
						|
        return s->irq_pending[index];
 | 
						|
    case AW_A10_PIC_FIQ_PENDING ... AW_A10_PIC_FIQ_PENDING + 8:
 | 
						|
        return s->fiq_pending[index];
 | 
						|
    case AW_A10_PIC_SELECT ... AW_A10_PIC_SELECT + 8:
 | 
						|
        return s->select[index];
 | 
						|
    case AW_A10_PIC_ENABLE ... AW_A10_PIC_ENABLE + 8:
 | 
						|
        return s->enable[index];
 | 
						|
    case AW_A10_PIC_MASK ... AW_A10_PIC_MASK + 8:
 | 
						|
        return s->mask[index];
 | 
						|
    default:
 | 
						|
        qemu_log_mask(LOG_GUEST_ERROR,
 | 
						|
                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
 | 
						|
        break;
 | 
						|
    }
 | 
						|
 | 
						|
    return 0;
 | 
						|
}
 | 
						|
 | 
						|
static void aw_a10_pic_write(void *opaque, hwaddr offset, uint64_t value,
 | 
						|
                             unsigned size)
 | 
						|
{
 | 
						|
    AwA10PICState *s = opaque;
 | 
						|
    uint8_t index = (offset & 0xc) / 4;
 | 
						|
 | 
						|
    switch (offset) {
 | 
						|
    case AW_A10_PIC_BASE_ADDR:
 | 
						|
        s->base_addr = value & ~0x3;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_PROTECT:
 | 
						|
        s->protect = value;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_NMI:
 | 
						|
        s->nmi = value;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_IRQ_PENDING ... AW_A10_PIC_IRQ_PENDING + 8:
 | 
						|
        /*
 | 
						|
         * The register is read-only; nevertheless, Linux (including
 | 
						|
         * the version originally shipped by Allwinner) pretends to
 | 
						|
         * write to the register. Just ignore it.
 | 
						|
         */
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_FIQ_PENDING ... AW_A10_PIC_FIQ_PENDING + 8:
 | 
						|
        s->fiq_pending[index] &= ~value;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_SELECT ... AW_A10_PIC_SELECT + 8:
 | 
						|
        s->select[index] = value;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_ENABLE ... AW_A10_PIC_ENABLE + 8:
 | 
						|
        s->enable[index] = value;
 | 
						|
        break;
 | 
						|
    case AW_A10_PIC_MASK ... AW_A10_PIC_MASK + 8:
 | 
						|
        s->mask[index] = value;
 | 
						|
        break;
 | 
						|
    default:
 | 
						|
        qemu_log_mask(LOG_GUEST_ERROR,
 | 
						|
                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
 | 
						|
        break;
 | 
						|
    }
 | 
						|
 | 
						|
    aw_a10_pic_update(s);
 | 
						|
}
 | 
						|
 | 
						|
static const MemoryRegionOps aw_a10_pic_ops = {
 | 
						|
    .read = aw_a10_pic_read,
 | 
						|
    .write = aw_a10_pic_write,
 | 
						|
    .endianness = DEVICE_NATIVE_ENDIAN,
 | 
						|
};
 | 
						|
 | 
						|
static const VMStateDescription vmstate_aw_a10_pic = {
 | 
						|
    .name = "a10.pic",
 | 
						|
    .version_id = 1,
 | 
						|
    .minimum_version_id = 1,
 | 
						|
    .fields = (VMStateField[]) {
 | 
						|
        VMSTATE_UINT32(vector, AwA10PICState),
 | 
						|
        VMSTATE_UINT32(base_addr, AwA10PICState),
 | 
						|
        VMSTATE_UINT32(protect, AwA10PICState),
 | 
						|
        VMSTATE_UINT32(nmi, AwA10PICState),
 | 
						|
        VMSTATE_UINT32_ARRAY(irq_pending, AwA10PICState, AW_A10_PIC_REG_NUM),
 | 
						|
        VMSTATE_UINT32_ARRAY(fiq_pending, AwA10PICState, AW_A10_PIC_REG_NUM),
 | 
						|
        VMSTATE_UINT32_ARRAY(enable, AwA10PICState, AW_A10_PIC_REG_NUM),
 | 
						|
        VMSTATE_UINT32_ARRAY(select, AwA10PICState, AW_A10_PIC_REG_NUM),
 | 
						|
        VMSTATE_UINT32_ARRAY(mask, AwA10PICState, AW_A10_PIC_REG_NUM),
 | 
						|
        VMSTATE_END_OF_LIST()
 | 
						|
    }
 | 
						|
};
 | 
						|
 | 
						|
static void aw_a10_pic_init(Object *obj)
 | 
						|
{
 | 
						|
    AwA10PICState *s = AW_A10_PIC(obj);
 | 
						|
    SysBusDevice *dev = SYS_BUS_DEVICE(obj);
 | 
						|
 | 
						|
     qdev_init_gpio_in(DEVICE(dev), aw_a10_pic_set_irq, AW_A10_PIC_INT_NR);
 | 
						|
     sysbus_init_irq(dev, &s->parent_irq);
 | 
						|
     sysbus_init_irq(dev, &s->parent_fiq);
 | 
						|
     memory_region_init_io(&s->iomem, OBJECT(s), &aw_a10_pic_ops, s,
 | 
						|
                           TYPE_AW_A10_PIC, 0x400);
 | 
						|
     sysbus_init_mmio(dev, &s->iomem);
 | 
						|
}
 | 
						|
 | 
						|
static void aw_a10_pic_reset(DeviceState *d)
 | 
						|
{
 | 
						|
    AwA10PICState *s = AW_A10_PIC(d);
 | 
						|
    uint8_t i;
 | 
						|
 | 
						|
    s->base_addr = 0;
 | 
						|
    s->protect = 0;
 | 
						|
    s->nmi = 0;
 | 
						|
    s->vector = 0;
 | 
						|
    for (i = 0; i < AW_A10_PIC_REG_NUM; i++) {
 | 
						|
        s->irq_pending[i] = 0;
 | 
						|
        s->fiq_pending[i] = 0;
 | 
						|
        s->select[i] = 0;
 | 
						|
        s->enable[i] = 0;
 | 
						|
        s->mask[i] = 0;
 | 
						|
    }
 | 
						|
}
 | 
						|
 | 
						|
static void aw_a10_pic_class_init(ObjectClass *klass, void *data)
 | 
						|
{
 | 
						|
    DeviceClass *dc = DEVICE_CLASS(klass);
 | 
						|
 | 
						|
    dc->reset = aw_a10_pic_reset;
 | 
						|
    dc->desc = "allwinner a10 pic";
 | 
						|
    dc->vmsd = &vmstate_aw_a10_pic;
 | 
						|
 }
 | 
						|
 | 
						|
static const TypeInfo aw_a10_pic_info = {
 | 
						|
    .name = TYPE_AW_A10_PIC,
 | 
						|
    .parent = TYPE_SYS_BUS_DEVICE,
 | 
						|
    .instance_size = sizeof(AwA10PICState),
 | 
						|
    .instance_init = aw_a10_pic_init,
 | 
						|
    .class_init = aw_a10_pic_class_init,
 | 
						|
};
 | 
						|
 | 
						|
static void aw_a10_register_types(void)
 | 
						|
{
 | 
						|
    type_register_static(&aw_a10_pic_info);
 | 
						|
}
 | 
						|
 | 
						|
type_init(aw_a10_register_types);
 |